United States

Cancers evade the immune system by inducing immunosuppressive tumor microenvironments (TMEs). Tumor cells release cytokines and growth factors that induce myeloid cell precursors to differentiate into an immunosuppressive cell population: myeloid-derived suppressor cells (MDSCs). In cancer patients, MDSCs are found in TMEs and in the blood, where their higher levels correlate with poor prognosis, increased disease progression, and reduced long-term survival. MDSCs are categorized into two major types: monocytic (M-MDSC) and granulocytic (G-MDSC), based on their molecular marker surface expression. In their normal physiologic role, MDSCs localize to the placenta, wounds, and other sites associated with immunosuppression and &#39;immune privilege’, where they potently suppress T and natural killer cells. However, MDSCs also accumulate with cancer and other pathogenic chronic inflammatory conditions such as sepsis and persistent viral infections. However, it remains unclear whether specific tumor types consistently favor enrichment of distinct MDSC subtypes. Our research aims to characterize tumors based on the MDSC subtypes present in their microenvironment and identify whether certain cancers induce MDSC differentiation into monocytic, granulocytic, or both. Our objective is to define tumor-specific MDSC profiles that could serve as biomarkers for immune evasion and guide targeted immunomodulatory therapies. We used a ‘tumor education’ model, an ex vivo tumor–primary CD14+ human monocyte co- culture to mirror MDSC generation during cancer progression. We examined melanoma and renal cell carcinoma in this system. We isolated myeloid cells from the co-cultures and used flow cytometry with antibodies against the following markers: CD33, CD11b, CD14, CD15, and HLA-DR, to determine whether MDSC phenotypes differed across tumor types and donors. Our model captured features of the distinct MDSC populations that are preferentially expanded across different cancer types. Specifically, we demonstrate that melanoma induces more M- MDSCs, whereas renal cell carcinoma (RCC) induces comparatively fewer M-MSDCs. These findings are consistent with the observed MDSC profiles in patients with these cancer types. Overall, our model provides insight into the mechanisms underlying MDSC heterogeneity in cancer and has the potential to support cancer patient MDSC screening that guides effective immunotherapies. We are using this assay as a prototype to model MDSC conversion in individual cancer patients, enabling precision oncology through screening of cancer-specific and personalized immunotherapies that reduce MDSC-mediated immunosuppression. Currently, we are expanding our model to include additional cancer types and incorporate a larger sample of donors.

AMA Research Challenge 2025 

Myeloid-Derived Suppressor Cells Express Diverse Biomarkers Across Tumor Type and are Potential Targets for Cancer-Specific and Personalized Immunotherapies


### WELCOME!

We’re connecting the scientific community and bringing the ultimate virtual summit to you. Learn about the latest trends in immunology from today’s influencers. Discover how they leverage high-dimensional biology to drive new discoveries and research. Earn CE credit. All from your browser. All at no cost to you.
<br>

### Gain insights from the following influencers in immunology: ###

Registration for this event is free. Please click on the button below to register.

Free registration

Insights Immunology 2021

We’re connecting the scientific community and bringing the ultimate virtual summit to you. Learn about the latest trends in immunology from today’s influencers. Discover how they leverage high-dimensional biology to drive new discoveries and research. Earn CE credit. All from your browser. All at no cost to you.

2021 Insights Immunology event page: https://underline.io/events/173/reception


Cancers evade the immune system by inducing immunosuppressive tumor microenvironments (TMEs). Tumor cells release cytokines and growth factors that induce myeloid cell precursors to differentiate into an immunosuppressive cell population: myeloid-derived suppressor cells (MDSCs). In cancer patients, MDSCs are found in TMEs and in the blood, where their higher levels correlate with poor prognosis, increased disease progression, and reduced long-term survival. MDSCs are categorized into two major types: monocytic (M-MDSC) and granulocytic (G-MDSC), based on their molecular marker surface expression. In their normal physiologic role, MDSCs localize to the placenta, wounds, and other sites associated with immunosuppression and 'immune privilege’, where they potently suppress T and natural killer cells. However, MDSCs also accumulate with cancer and other pathogenic chronic inflammatory conditions such as sepsis and persistent viral infections. However, it remains unclear whether specific tumor types consistently favor enrichment of distinct MDSC subtypes. Our research aims to characterize tumors based on the MDSC subtypes present in their microenvironment and identify whether certain cancers induce MDSC differentiation into monocytic, granulocytic, or both. Our objective is to define tumor-specific MDSC profiles that could serve as biomarkers for immune evasion and guide targeted immunomodulatory therapies. We used a ‘tumor education’ model, an ex vivo tumor–primary CD14+ human monocyte co- culture to mirror MDSC generation during cancer progression. We examined melanoma and renal cell carcinoma in this system. We isolated myeloid cells from the co-cultures and used flow cytometry with antibodies against the following markers: CD33, CD11b, CD14, CD15, and HLA-DR, to determine whether MDSC phenotypes differed across tumor types and donors. Our model captured features of the distinct MDSC populations that are preferentially expanded across different cancer types. Specifically, we demonstrate that melanoma induces more M- MDSCs, whereas renal cell carcinoma (RCC) induces comparatively fewer M-MSDCs. These findings are consistent with the observed MDSC profiles in patients with these cancer types. Overall, our model provides insight into the mechanisms underlying MDSC heterogeneity in cancer and has the potential to support cancer patient MDSC screening that guides effective immunotherapies. We are using this assay as a prototype to model MDSC conversion in individual cancer patients, enabling precision oncology through screening of cancer-specific and personalized immunotherapies that reduce MDSC-mediated immunosuppression. Currently, we are expanding our model to include additional cancer types and incorporate a larger sample of donors.

poster

Congratulations to all the researchers who have qualified for the AMA Research Challenge virtual poster symposium and semifinals!

Welcome to the **largest national, multi-specialty research event** featuring research from nearly 1,000 medical students, residents, fellows, and international medical graduates across six topic areas - basic science, clinical and translational research, clinical vignettes, health systems science, medical education, and public health and health policy.

#### Access the Event
Use the buttons below or navigation menu to access the event. 

[![](https://assets.underline.io/markdown_image/1/image/d4076f2146939317a29eb9f69c53ad41.png)](https://underline.io/events/506/sessions?searchGroup=all)
[![](https://assets.underline.io/markdown_image/1/image/6bcee0b523a4874c4292ca0415d88dde.png)](https://underline.io/events/506/posters?searchGroup=all)

#### Event Details
The 2025 AMA Research Challenge includes the following symposium halls:
* **Semifinals hall:** Features research from 54 medical students, residents and international medical graduates that received top scores during first round scoring. 
* **Poster symposium hall:** Features research from nearly 1,000 medical students, residents and international medical graduates categorized by topics and subtopics.

**Here’s how to participate:**
* **View posters and presentations** on a variety of topics and specialties
* **Score posters in the semifinals** to help decide the top five finalists (AMA member exclusive opportunity)
* **Connect with presenters** and provide feedback to help advance their research
* **New this year: Watch live poster presentations** by topic area and engage directly with researchers

At the conclusion of this event, the AMA announced the top five finalists who advanced to the AMA Research Challenge final round, presented their research to an elite panel of judges, and competed to win a $10,000 grand prize presented by Laurel Road.

**Addison Shenk, a fourth-year medical student from Edward Via Virginia College of Osteopathic Medicine, was the winner of the 2025 AMA Research Challenge and was awarded the grand prize of $10,000, presented by Laurel Road.**

#### A message from Dr. Bobby Mukkamala, AMA President
<div style="position: relative; width: 100%; padding-bottom: 56.25%; height: 0; overflow: hidden;">
  <iframe 
    src="https://underline.io/embed/136894-ama-video?t=0"
    title="AMA Welcome Video"
    allowfullscreen
    style="position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: 0;">
  </iframe>
</div>


#### Recognized Institutions
In 2025, 1,400 abstracts were submitted across six topic areas representing 174 medical schools and more than 150 residency and health care institutions. [See if your institution is represented this year!](https://drive.google.com/file/d/1eFrTqCmCeobx9pr5drJK2hllvsIpFNOY/view?usp=drive_link)

#### Grand Prize Sponsor
AMA would like to thank Laurel Road, a brand of KeyBank, for sponsoring a $10,000 grand prize for the winner of the AMA Research Challenge. Laurel Road and KeyBank are not involved in winner selection process. The winner will be announced during the AMA Research Challenge final round. Payment of the grand prize will be directly from Laurel Road/KeyBank. See the [AMA Research Challenge Official Rules for terms and conditions](https://www.ama-assn.org/system/files/research-challenge-official-rules.pdf).

[![](https://assets.underline.io/uploads/markdown_image/1/image/611e331d4a0eba0920f240cfc04b4d77.png)](https://www.laurelroad.com/)

#### Code of Conduct
<html>
AMA has a code of conduct for its meetings – we ask all attendees to adhere to this code to participate in this year’s meeting. Please read and <a href="https://www.ama-assn.org/about/code-conduct" target="_blank">learn more here</a> about your conduct requirements.
<br><br>
	</html>
	

#### Semifinals Judges

You need to log in with the email address you registered with. Access credentials have been sent to your email. 

Please be sure to check your spam and other email folders if you do not see an email confirmation right away.

Need help? Contact us at <support@underline.io>.

Please log in to explore this event.

If you have used the AMA Research Challenge platform previously, please click the ‘Log-in’ button below. If you do not remember your password, please click “forgot password” and follow prompts to reset your password. After resetting your password, please refresh your webpage to access the platform. 

Register to explore research in a variety of topics. AMA members get exclusive access to score posters in the semifinals. 

**Please use [this link here](https://www.ama-assn.org/member-benefits/events/ama-research-challenge) to register for free. **

Registration Is Required

Join the AMA Research Challenge poster symposium and semifinals to explore top research posters and score posters in the semifinals (an AMA member exclusive opportunity).

In the past two decades, oncolytic viruses (OVs) have emerged as a promising candidate for cancer treatment by utilizing genetically modified viruses to target and deliver anti-tumor reagents precisely. These CRISPR-modified oncolytic viruses elicit reduced pathogenicity yet preserve cytotoxicity and tissue specificity, allowing for dual antitumor effects: the target-specific delivery of tumor microenvironment (TME) immune-enhancers and initiation of antiviral immunity. We performed systematic literature searches of the PubMed databases that pertain to oncolytic viruses and the delivery of reagents that target immunosuppressive factors in the TME. We intend to look at multiple study designs that followed clinical trial phases, being tested first in animal models and then followed by safety and efficacy in humans. Oncolytic viruses paired with several different anti-immunosuppressive reagents were identified, namely, anti-PD-1, anti-CTLA-4, anti-PD-L1, anti-GM-CSF, and anti-TGFβ. As outlined in this work, the different anti-immunosuppressive reagents co-expressed and co-delivered with the oncolytic virus have shown to be a promising new method to be further explored in patients with local and metastatic tumors. We anticipate that future directions include, but are not limited to, novel pharmacologic cargos, circumnavigating immune-restricted cancer sites, and the usage of oncolytic viruses for tangent diseases.

Harnessing Viruses for Good: Advancements and Efficacy in Oncolytic Virus Therapy 
for Cancer

Abstract Title
Effect of Climate and Energetics within Southeast Asian Nasal Morphology 

Authors: Isaac Nebeker1, Fabio Savoldi2, James Kit-Hon Tsoi3, Michael Rivera4, Andy Wai Kan Yeung5, Alexa P. Kelly1

1Campbell University School of Osteopathic Medicine; 2University of Brescia, Orthodontics, Dental School, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health 3The University of Hong Kong, Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry 4The University of Hong Kong, Faculty of Social Sciences 5The University of Hong Kong, Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, 


Background
Under normal breathing (eupnea), virtually all inspired air must pass through the internal nasal cavity. Recent research has revealed that inspiration functionality may vary according to environmental climate and body size constraints. In turn, these constraints have altered the shape and size of not only the nose, but total craniofacial anatomy, over the course of human history. Populations indigenous to colder-drier environments consistently exhibit taller, narrower, and longer internal noses. This morphological adaptation increases the heating and humidification of inspired air, as well as satisfies metabolic oxygen demand. Thus far, studies evaluating the effects of energetics and environmental climate on nasal morphology have not incorporated large samples of humans from hot-humid climates. Accordingly, this study aimed to quantify nasal variation in the context of climate and body size in a large sample of humans from Southeast Asia.

Methods
We employed three-dimensional geometric morphometrics, a quantitative methodology widely used in biological anthropology, facilitated by recent advancements in 3D imaging technology that allow for high-resolution analysis of craniofacial structures. In this study, computed tomography (CT) scans were obtained from 63 individuals (11 females, 52 males) curated in the Human Bone Collection at The University of Hong Kong. Using 3D Slicer imaging software, forty-nine three-dimensional coordinate landmarks were systematically recorded on the cranial CT scans and then utilized in Procrustes-based shape analysis. Additionally, body mass and climate-specific basal metabolic rate (BMR) were estimated through established predictive equations applied to postcranial skeletal elements associated with each cranium.

Results
In this sample, significant sexual dimorphism was observed in both BMR (p < 0.0003) and nasal centroid size (p < 0.0001), with males exhibiting larger internal nasal structures and higher metabolic rates. While nasal height (p = 0.398) and breadth (p = 0.114) were not significantly associated with BMR, nasal length was (p < 0.025), suggesting a relationship between internal nasal elongation and energetic demand. Additionally, a progressive increase in nasal height and length was observed in individuals with high BMRs.

Conclusion
These findings suggest that in hot, humid environments where ambient air is closer to core body temperature and humidity, evolutionary pressures on nasal height and breadth for air conditioning are reduced. Instead, nasal morphology appears to reflect a balance between respiratory efficiency and thermoregulation, particularly through increases in nasal length to accommodate metabolic demand. This has important implications in otolaryngology; especially in our increasingly globalized world wherein individuals are frequently inhabiting diverse environments with greater frequency.


Effect of Climate and Energetics within Southeast Asian Nasal Morphology

Abstract Title: 3D Modeling and Virtual Implantation of Pediatric Leadless Pacemakers: Predictors of Acute Implant Angles

Background
Leadless pacemakers (LP) have advantages for treatment of arrhythmic disease in pediatric patients including high efficacy and lower rates of complications when compared to technologies involving leads. Anatomical differences among pediatric patients, including vertical cardiac orientation (acute IVC-to-target implant location angle) can make delivery catheter positioning and device implantation difficult. Early clinical experience at our institution suggests that access from the right internal jugular vein can aid in crossing of the tricuspid valve and improve catheter maneuverability. In this exploratory analysis we used 3D modeling of cross-sectional imaging to measure implantation angles from the IVC and SVC and correlate these features with anthropomorphic traits to aid in procedural planning.

Methods
Data collection/Inclusion Criteria: CT-Angiography scans obtained from 2022-2025 representing a varied pediatric cohort were collected. Patients with structural heart disease or non-diagnostic scans were excluded.
Modeling: 3D Slicer was used to create models from scans via combined automatic segmentation with manual refinement. Pacemaker implant location at the apical third of the ventricular septum was identified. IVC-implant angle (IVCia) and SVC-implant angle (SVCia) were recorded. Virtual implant was performed using high-fidelity pacemaker model created using photogrammetry.
Data analysis: Descriptive statistics for the cohort were completed with grouped comparisons by age, height, weight, and BMI quartiles.

Results
51 patients were included (29 Female [57%], mean age 13 ± 3.7 yrs, height 153 ± 20 cm, weight 56 ± 27 kg, BMI mean 20 ± 7). The mean IVCia was significantly more acute than the SVCia (81 ± 17 vs. 116 ± 12, p < 0.01). IVCia became more acute with increasing age (<10 y (n=11) 100.7 ± 27.2, 10-14 y (n=18) 82.2 ± 14.6, 14-18y (n = 24) 77.5 ± 15.7), p = 0.017) while SVCia was age-invariant. No significant difference in weight, height, or BMI quartiles were noted for IVCia or SVCia. A single patient was noted to have less than 1 cm from the tricuspid valve annulus to the proximal end of the pacemaker.

Conclusion
In this our exploratory analysis, we found that the IVCia was more acute than the SVCia, suggesting that jugular approach may be easier in the majority of pediatric patients. The youngest patients in the cohort had the least acute IVCia, but no other patient characteristics were predictive of implant angle. Future studies correlating readily available studies such as plain chest film to IVCia/SVCia may prove to be of significant benefit. 





3D Modeling and Virtual Implantation of Pediatric Leadless Pacemakers: 
Predictors of Acute Implant Angles

Background
The Model for End-Stage Liver Disease (MELD) score has helped prioritize liver transplant candidates based on disease severity since 2002. Changes to its algorithm rendered MELD 2.0 in 2016 and MELD 3.0 in 2022. The revisions to each model aimed to enhance transplant allocation and equity, but each model’s ability to predict post-transplant outcomes remains unclear.

Methods
Utilizing the Organ Procurement Transplantation Network database, 10 post-transplant outcomes were compared between MELD 1.0 (n=76,732), MELD 2.0 (n=52,615), and MELD 3.0 (n=23,299) cohorts. Binary logistic regression models evaluated the association between MELD cohort and each dichotomous outcome, adjusting for MELD score. MELD 1.0 served as the reference category. Odds ratios (ORs), 95% confidence intervals (CIs), and p-values were reported for comparisons between MELD 2.0 versus MELD 1.0 and MELD 3.0 versus MELD 1.0. Statistical significance was defined as p<0.05. All analyses were conducted using IBM SPSS Statistics, version 29.

Results
MELD 3.0 best predicted an increased risk of graft failure due to infection (OR=1.30, p=0.02), diffuse cholangitis (OR=2.32, p<0.001), hepatic artery thrombosis (OR=2.51, p<0.001), primary non-function (OR=3.93, p<0.001), and overall graft loss (OR=6.34, p<0.001). MELD 3.0 also was the greatest predictor of a decreased risk in chronic rejection (OR=0.67, p=0.041), recurrent disease (OR=0.12, p<0.001), and hepatitis recurrence (OR=0.03, p<0.001). However, an increased risk of acute rejection (OR=1.58, p<0.001) was better predicted by MELD 2.0. Graft failure due to other vascular thrombosis was not significantly predicted by either model.

Conclusion
MELD model revisions may have utility in predicting post-transplant outcomes as evidenced by the 3.0 model best predicting 8 out of the 10 selected outcomes. Further studies should examine the ability of MELD 3.0 to predict male versus female transplant outcomes, as the purpose of the MELD 3.0 revision was to improve equitable distribution of available livers to females.

Investigating the Utility of Each MELD Edition in Predicting Liver Transplant Outcomes

Background
Perforator flaps, like deep inferior epigastric perforator (DIEP) and thoracodorsal artery perforator (TDAP) flaps, use perforating vessels to transfer tissue while sparing underlying muscle and motor nerves in microvascular reconstruction. Obtaining computed tomography angiograph (CTA) studies prior to flap surgeries is the gold standard for identifying appropriate perforators. Although CTA provides high-quality vascular imaging, concerns persist regarding the potential risks of radiation exposure and the financial costs associated with its use. This systematic review assesses how different preoperative imaging methods correlate with complication rates.
Methods
A systematic review was conducted using controlled keywords across multiple databases to identify studies utilizing preoperative CTA imaging in patients undergoing DIEP breast reconstruction published up to 2024. Keywords utilized included ("flap surgeries" OR "flap surgery" OR "flap procedures" OR “DIEP” OR “Autologous breast reconstruction” OR “deep inferior epigastric artery flap”) AND ("preoperative identification" OR "perforator vessels" OR "CTA" OR "Computed Tomography Angiography"). Eligible studies included clinical trials, observational studies, case series, and reports involving patients aged 18 or older. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were utilized. Each study went through a two-stage review process including an initial title and abstract screening followed by a full-text screening with two reviewers using Covidence software. 19 studies met inclusion criteria and data were abstracted into Excel by study design, total population, preoperative imaging type used, and complications.
Results
Out of 19 studies included, there were 3043 patients included in studies that shared complication rates. 499 patients (16.4%) reported complications during or after surgery. When our analysis was subdivided by preoperative imaging type, 134 of 625 (21.4%) US alone, 115 of 622 (18.5%) CTA alone, and 87 of 603 (14.4%) US + CTA patients reported complications. Of the total 499 patients with complications, 40 (8.0%) suffered complete flap loss, 69 (14%) experienced partial flap loss, and 96 (19%) developed fat necrosis.
Conclusion
Our preliminary analysis demonstrates that studies utilizing CTA alone or with US for preoperative planning reported lower rates of complications when compared to studies using US alone. These findings suggest while preoperative CTA is demonstrated to decrease intraoperative times, it may also be associated with better surgical outcomes in DIEP breast reconstructions. These findings emphasize the need for accurate preoperative perforator identification in minimizing complications and optimizing surgical outcomes.


Evaluating the Efficacy of Preoperative CTA in DIEP Flap Breast Reconstructions

Background
With 890,000 new diagnoses and 450,000 deaths each year, head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide. Pathologic extranodal extension (pENE)—defined as histopathologically-evident tumor growth beyond the lymph node capsule—is an important prognostic factor for HNSCC.
pENE+ cancers are more aggressive, more difficult to remove surgically, and more likely to metastasize. Thus, pENE presently serves as an indication for more intensive treatment, including adjuvant chemoradiation. In this study, progression-free survival outcomes were compared by pENE status to determine whether current treatment approaches adequately address the increased risks posed by pENE+ cancer.

Methods
A retrospective review was performed of 146 patients with HNSCC, a subset of the Holden Comprehensive Cancer Center’s BioMER cohort. Patients were excluded if they never received surgical intervention, if their cancer was human papillomavirus (HPV)-positive, or if they presented with recurrent disease originally treated at other institutions.
Data was extracted from clinical records in Epic, stored in a secured REDCap database, and anonymized prior to analysis in SPSS Statistics. Survival outcomes were compared using log-rank tests, while chi-square or Fisher’s exact tests were used for all other analyses.

Results
Patients who were pENE+ had significantly worse progression-free survival outcomes (P < 0.0001) than patients who were pENE-. There was also a trend towards worse overall survival, which did not reach statistical significance (P = 0.2255). Interestingly, macroscopic pENE (>2mm) was associated with significantly worse overall survival compared to microscopic pENE (<2mm) (P = 0.0387).
In investigating correlations with other variables, tumors with poor differentiation (P = 0.0004), advanced T stage (P = 0.0053), or distant metastasis (P = 0.0045) were all significantly more likely to be pENE+.

Conclusion
Despite relatively aggressive treatment regimens, pENE+ patients still suffer from significantly higher rates of recurrence. pENE status was also strongly associated with several other indicators of aggressive tumor behavior.
One limitation of this study was the relatively short follow-up period, which may have limited the statistical power of some analyses.
Further research is needed to determine how we can fulfill this unmet clinical need and improve outcomes for pENE+ patients. One promising approach involves radiologic ENE, which could potentially enable accurate risk stratification and treatment planning from the first diagnostic scan.

Pathologic extranodal extension: an undervalued prognostic factor in head and neck squamous cell carcinoma

Background: Post-COVID-19 complications have been reported in up to 60% of infections globally, contributing to a significant burden on public health and quality of life. Among these complications, persistent immune dysregulation and inflammatory syndromes, such as mast cell activation syndrome (MCAS), have been increasingly recognized. MCAS is characterized by an exaggerated and inappropriate mast cell response, resulting in widespread systemic inflammation and allergic-like symptoms. Understanding these phenomena is critical for improving diagnostic strategies and therapeutic approaches. In this report, we present a rare case of transient MCAS-like hypersensitivity symptoms following COVID-19 reinfection, with a notably intensified symptom presentation compared to the initial infection.

Case Presentation: A 33-year-old male with a past medical history of asthma and obesity presented with unusual post-COVID hypersensitivity symptoms. Following an initial COVID-19 infection two years prior, he developed transient, mild diffuse epidermal pruritus triggered by sugary foods, which resolved spontaneously after two weeks. However, after a second infection in April 2024, he experienced severe hypersensitivity reactions resembling anaphylaxis, including diffuse pharyngeal and distal extremity swelling, pruritic urticaria, dyspepsia, diarrhea, persistent left lower quadrant abdominal and lumbar pain, wheezing, and nausea. Symptoms were triggered by ingestion of nearly all foods except red meats seasoned only with sea salt. Comprehensive evaluation, including upper gastrointestinal biopsy, ruled out celiac disease, and a full allergy panel showed no food allergies. Laboratory workup and physical examination revealed no abnormalities. Symptoms gradually resolved over a four-month period without targeted intervention.

Discussion: MCAS is typified by inappropriate mast cell degranulation, leading to the release of pro-inflammatory mediators and systemic symptoms such as fatigue, gastrointestinal distress, and dermatologic manifestations. Nonspecific mast cell activation following COVID-19 infection remains a rare but increasingly reported complication. In this case, symptom severity was markedly intensified following reinfection compared to the initial episode, reflecting a pattern akin to the immune system’s heightened response following booster COVID-19 vaccinations. We propose that reinfection may further prime mast cells, precipitating an exaggerated inflammatory response and more severe clinical manifestations. The absence of food-specific IgE antibodies supports a non-IgE-mediated hypersensitivity mechanism, consistent with mast cell dysregulation. Although MCAS-like reactions post-COVID are rare, accumulating evidence suggests they are not isolated occurrences. Greater awareness and further studies are warranted to elucidate the pathophysiology, improve diagnostic criteria, and develop effective management strategies to enhance the quality of life for affected patients.

Transient Mast Cell Activation Syndrome-Like Hypersensitivity Following
COVID-19 Reinfection: A Case Report of Intensified Symptomatology

Abstract Title
Halo Nevi with Poliosis: A Scoping Review and Case Report

Background:
Halo nevi (HN) are benign melanocytic nevi surrounded by a depigmented ring, typically occurring on the trunk. Rarely, they may appear on the scalp and can present with poliosis, a localized white patch of hair. This uncommon presentation poses diagnostic and management challenges. We present a case of scalp halo nevi with poliosis in a pediatric patient and review the literature to characterize clinical, histological, and management patterns.

Methods:
A comprehensive literature search was conducted across multiple databases including MEDLINE, CINAHL, Cochrane Collection, and Web of Science, limited to English-language articles through October 2024. Search strategies incorporated relevant Medical Subject Headings (MeSH) and textword searches. Identified citations were screened using Covidence, and relevant case reports were extracted for clinical and histopathologic data.

Results:
Our case involves a 9-year-old female with three pink macules and intralesional white hairs on the scalp. Biopsy confirmed a briskly inflamed intradermal melanocytic nevus consistent with a halo nevus. Follow-up at three months showed persistence of two lesions and spontaneous resolution of one.

Literature review identified six prior cases of halo nevi with poliosis on the scalp and two involving the eyelid. Most patients were children or young adults. Common histopathologic findings included dense dermal lymphocytic infiltrates surrounding melanocytic nests with a decrease in follicular melanocytes in some cases. Dermatoscopy, when reported, showed depigmentation, globules, and poliosis. Treatment was typically conservative, with excision pursued for cosmetic reasons or concern for atypia. No recurrences or adverse outcomes were reported.

Conclusion:
Halo nevi with poliosis are rare, especially on the scalp, and primarily affect children. Though benign, these lesions can mimic pigmentary disorders or melanoma-associated leukoderma. Biopsy remains the diagnostic gold standard, with dermatoscopy serving as a useful adjunct, though underreported in this context.
Current literature is limited to isolated case reports without standardized management or long-term outcomes, and no consistent association with vitiligo has been observed in cases presenting with poliosis. Clinicians should manage these lesions conservatively, offering reassurance and reserving intervention for diagnostic uncertainty or cosmetic concerns. Improved documentation of dermatoscopic and histopathologic findings will enhance recognition and inform future clinical guidance for this uncommon presentation.


Halo Nevi with Poliosis: A Scoping Review and Case Report

A Small Polyp with a Big Impact: Metastatic Duodenal NET Initially Presenting with PE & Pancytopenia

Background
Neuroendocrine tumors (NETs) are rare malignancies emerging from neuroendocrine cells, accounting for <1% of all cancers. The gastrointestinal (GI) tract represents the primary site for these tumors but duodenal NETs (D-NETs) occur exceptionally rarely because they make up only 2% of GI NETs. Typically slow-growing and asymptomatic —especially when <2 cm—these tumors are often discovered incidentally. However, some may metastasize and present atypically. We report a rare case of a metastatic D-NET arising from a 3–4 mm duodenal polyp, initially presenting with pulmonary embolism (PE), pancytopenia, and systemic symptoms.

Case Presentation
A 72-year-old African American woman with hypertension and GERD presented with left arm swelling, generalized weakness, and significant unintentional weight loss. CT angiography revealed bilateral submassive pulmonary emboli and parenchymal lung disease. Doppler ultrasound showed DVTs in the left upper and lower extremities. Labs demonstrated anemia, leukocytosis, and hypoalbuminemia. Given concern for malignancy, a CT-guided lung biopsy identified a well-differentiated grade 2 NET (Ki-67 index 5%) with markers suggestive of GI or pancreatobiliary origin. Bone scan showed osseous involvement, raising concern for widespread metastatic disease and bone marrow suppression contributing to pancytopenia.
Esophagogastroduodenoscopy revealed a 3–4 mm duodenal bulb polyp, which was
confirmed on biopsy as the primary tumor—a well-differentiated grade 2 NET. The
patient was treated with anticoagulation and discharged in stable condition with plans for PET imaging and oncology follow-up.

Discussion
This case illustrates an unusual presentation of metastatic D-NET from a lesion <5 mm in size. While most small duodenal polyps are benign, this case challenges the
assumption that size correlates with clinical risk. The initial presentation with PE and
pancytopenia illustrates the diverse and sometimes misleading ways NETs can
manifest, particularly when metastasized. Diagnosis hinges on histopathologic
confirmation with immunohistochemistry. Although small, localized D-NETs are often cured with endoscopic resection, metastatic cases require systemic therapy and close surveillance. Clinicians should maintain a broad differential when evaluating unexplained hypercoagulability and cytopenias, recognizing that even minute GI lesions can harbor significant malignant potential.

A Small Polyp with a Big Impact: Metastatic Duodenal NET Initially Presenting with PE and Pancytopenia

Gemella Sanguinis is a gram positive, facultative anaerobic bacteria that is normally found in mucosal surfaces of oropharynx, gastrointestinal and genitourinary systems. Gemella species can cause bacteremia and is a rare cause of infective endocarditis particularly in patients with underlying cardiac and valvular disease. The main source of gemella bacteremia is oral from dental infections but has also been reported in patients with colon malignancies. We present an interesting case of Gemella Sanguinis bacteremia with mitral valve endocarditis in a patient with colon cancer.

CASE:

61 year old male with history of rheumatic heart disease, atrial fibrillation, hypertension presented with chief complaints of fevers, chills, cough and shortness of breath for 3 weeks. He had a 15- pack year history of smoking but denied alcohol or substance abuse. There was no family history of malignancies. Upon initial presentation he was hypotensive and required vasopressors for severe sepsis with shock. Broad spectrum antibiotics was initiated for sepsis. Cardioversion was performed since he was noted to be in atrial fibrillation with rapid ventricular response. His blood cultures grew Gemella Sanguinis. After review of the susceptibilities for gemella sanguinis, he was successfully treated with rocephin for 6 weeks. Gentamicin was not administered secondary to concern for acute kidney injury. Transthoracic echocardiogram revealed thickened anterior mitral valve leaflet with diastolic doming consistent with rheumatic valve disease. Transesophageal echocardiogram was performed that showed severe aortic valve stenosis, severe mitral valve stenosis with a 1 X 1.3 cm echo density on the anterior mitral valve leaflet consistent with a vegetation. Aortic and mitral valve replacement with mechanical prosthesis and extensive biatrial modified maze procedure was performed. Panorex films was performed that did not reveal oral source of infection. CT abdomen/pelvis showed diffuse wall thickening involving the sigmoid colon. Colonoscopy was done that revealed colorectal mass and biopsy was consistent with adenocarcinoma. He underwent colorectal resection with loop ileostomy and surgical margins were negative. His hospital course was further complicated by intraabdominal fluid collection and subdural hemorrhage. Oncology was consulted but secondary to low risk for recurrence chemotherapy was not recommended. He underwent colostomy reversal and continues to follow up with oncology.

CONCLUSION:

There are well known association between colon cancers and bacteremia including gemella species as presented above in this patient. Bacteria can enter the blood stream from disruption of the colonic barrier and intestinal dysbiosis. In a patient presenting with gemella sanguinis bacteremia with no clear source, clinicians should consider colonic etiologies and colonoscopy is warranted to search for underlying colonic malignancies. Appropriate timely diagnosis and workup enables early diagnosis and treatment.

Premium content

Downloads

Next from AMA Research Challenge 2025

Harnessing Viruses for Good: Advancements and Efficacy in Oncolytic Virus Therapy for Cancer

Similar lecture

A single-cell multiomics approach to study tumor-driven perturbations during hematopoiesis in mice