Diagnosis Of Merkel Cell Carcinoma Research Articles

The prognostic value of the Merkel cell polyomavirus serum antibody test: A dual institutional observational study.

Merkel cell carcinoma (MCC) is an aggressive cancer with often poor outcomes. Limited biomarkers exist for predicting clinical outcomes. The Merkel cell polyomavirus (MCPyV) serum antibody test (AMERK) has shown potential for indicating better recurrence-free survival in a single-institution study. The study aimed to evaluate the link between initial AMERK serostatus and survival. Secondary objectives included examining the relationship between initial AMERK titer levels and tumor burden. A retrospective cohort study across two institutions analyzed patients tested with AMERK within 90 days of MCC diagnosis. Regression models assessed the association of survival outcomes with serostatus, considering various factors. The relationship between AMERK titer and tumor burden indicators was evaluated using ANOVA. Significance testing was exploratory, without a fixed significance level. Of 261 MCC patients tested, 49.4% were initially seropositive (titer ≥75). Multivariable analysis showed that seropositivity improved recurrence, event-free, overall, and MCC-specific survival rates. Strong associations were found between initial AMERK titer and clinical, tumor, and nodal stages, tumor size, and disease extent. Notably, improved survival with seropositivity was observed only in patients with localized disease at initial presentation. Circulating antibodies to MCPyV oncoproteins, as indicated by the AMERK test, are linked with better survival in MCC patients with localized disease at presentation. This could enhance patient risk profiling and treatment personalization. The study's retrospective nature and exploratory analysis are key limitations. Merkel cell carcinoma (MCC) is a potentially aggressive skin cancer, and tools to predict patient outcomes are limited. A blood test called anti-Merkel cell panel (AMERK), which checks for specific antibodies related to this cancer, might give us some clues. In this study, we looked at 261 MCC patients who took the AMERK test within 90 days of diagnosis. We found that patients with an initial positive AMERK result tended to have better outcomes, especially if their cancer was in the early stages. However, it is important to note that this study has limitations, including using retrospective data and exploratory analyses.

Abstract 6107: Survival differences by socioeconomic status in Merkel cell carcinoma: A retrospective analysis using the National Cancer Database

Abstract Introduction: Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer whose incidence and survival outcomes demonstrate disparities based on patients’ socioeconomic status (SES). This study aims to evaluate the impact of SES on MCC diagnosis age, comorbidity burden, treatment modalities, and survival outcomes using the National Cancer Database. Methods: We conducted a retrospective analysis of 9742 patients diagnosed with MCC from 2016 to 2020 in the United States. To assess how socioeconomic status influences outcomes, a composite score was created by adding income and education quartile assignments (1, 2, 3, 4), to create new composite SES quartiles of 2-3, 4-5, 6-7, and 8. Patients were stratified into quartiles based on their SES (lowest Q1 to highest Q4). Binomial test was performed for categorical variables and ANOVA was performed for continuous. Survival differences were examined with Cox proportional hazards models and Kaplan-Meier curves. Results: Patients with lower SES presented with MCC at younger ages, with the average age of patients in the lowest SES Q1 being 73.8 years (95% CI 73.15-74.35) and the highest SES Q4 being 75.0 years (95% CI 74.48-75.46). Patients in SES Q1 also had higher Charson-Deyo scores, indicating more comorbidities than patients in SES Q4 (8.41% vs 5.8%, p < 0.001). They were also more likely to have advanced stage 4 MCC (9.67% vs 7.79%, p < 0.01) compared to patients in SES Q4. When treated with surgery, patients in SES Q1 were more likely to be treated with local tumor excision (14.39% vs 10.83%, p < 0.001) whereas patients in SES Q4 were more likely treated with Mohs surgery (5.02% vs 3.56%, p < 0.01). Survival probabilities for patients SES Q1 were worse at 1 year (82.99% vs 85.81%, p<0.001), 3 years (61.18% vs 68.49%, p < 0.001) and 5 years (45.99% vs 55.09%, p < 0.001) compared to patients in SES Q4. Conclusion: This study highlights disparities in age at diagnosis, comorbidities, treatment, and survival outcomes in MCC patients based on SES. Patients in lower SES quartiles are diagnosed younger, bear higher comorbidity burdens, and have worse rates of survival. Citation Format: Rachel C. Chang, Elise K. Brunsgaard, David Reid. Survival differences by socioeconomic status in Merkel cell carcinoma: A retrospective analysis using the National Cancer Database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6107.

Patterns of initial distant metastases in 151 patients undergoing surveillance for treated Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is associated with high rates of recurrence and distant metastatic progression. Current guidelines for surveillance imaging are not evidence based. Better characterization of the pattern of distant metastatic spread will better inform surveillance and facilitate earlier detection of metastases. This retrospective study aimed to assess potential relationships between primary tumour site and site of initial distant metastasis, time to distant metastasis, overall survival (OS) and MCC-specific death (MSD). Patients with local or regional (Stage I-III) disease who were treated with curative intent and progressed to Stage IV were included in this study (n = 151). Fisher's exact test was used to assess differences in patterns of initial distant metastases based on primary tumour site. Time to initial distant metastasis was calculated from date of MCC diagnosis. OS and MSD were calculated from date of initial distant metastasis to date of death from any or MCC-related causes, respectively. Of 151 patients included in analysis, 89 (58.9%) had a single initial distant metastatic site, and 62 (41.1%) had multiple sites. Patients with upper limb primary tumours were significantly less likely to develop distant lymph node or liver metastases (p = 0.02 and 0.04, respectively). Median time to distant metastasis was 11 months (IQR 6.7-17.9 months). Median OS was 15.3 months, and was shorter for patients with liver (7.0 months, p = 0.0004) or bone metastases (8.9 months, p < 0.0001). Using skin/soft tissue metastasis as a reference group, patients with multiple metastatic sites had significantly higher hazards of MSD (HR = 3.46 univariate, 3.77 multivariate analysis). Time to distant metastasis, OS and MSD did not differ by viral status. Sites of initial distant metastasis are related to primary tumour sites and survival outcomes. Because patients often have multiple initial metastases, full-body cross-sectional rather than region-specific imaging may facilitate earlier detection of metastatic disease.

Double Primary Cancers of Earlobe Merkel Cell Carcinoma and Lung Adenocarcinoma.

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine carcinoma with a high rate of metastasis. MCC is rarely suspected during clinical examination, thus requiring biopsy to establish a pathologic diagnosis. In addition, MCC sometimes occurs in double primary cancers. Although there have been reviews on double primary cancers, only a few cases involving MCC have been described. Herein, we report a case of a 54-year-old female patient who presented to our clinic with a diagnosis of earlobe MCC following an excisional biopsy performed by another clinic. Further evaluation, including chest imaging, revealed a mass in the lung. The patient underwent a wide excision of the right earlobe, and video-assisted thoracic surgery on the lung. Pathology confirmed MCC in the right earlobe and adenocarcinoma in the lung. The patient underwent postoperative adjuvant chemotherapy followed by radiotherapy. Up to this point, 3 years after the surgery, there has been no evidence of recurrence.

The diagnostic utility of Merkel cell polyoma virus immunohistochemistry in cytology specimens.

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine neoplasm that predominantly affects elderly and immunocompromised patients. Merkel cell polyoma virus (MCPyV) is clonally integrated into the majority of MCCs and has been linked to patient outcomes, playing a central role in the pathogenesis of the disease. We aimed to assess the utility of MCPyV immunohistochemistry (IHC) in the diagnosis of MCC in cytology cell block specimens and correlating with clinicopathologic features. Fifty-three cytology samples of MCC with sufficient cell block material were stained for MCPyV by IHC and scored semi-quantitatively in extent and intensity. Morphologic mimics of MCC including small cell lung carcinoma (n = 10), non-Hodgkin lymphoma (n = 10), basaloid squamous cell carcinoma (n = 6) and other neuroendocrine carcinomas (n = 8) were stained in parallel. Positive staining was defined as >1% of the tumour cells showing at least moderate staining intensity. The cytologic features of MCC were characterized by high nuclear-cytoplasmic ratios, hyperchromatic nuclei with 'salt and pepper' chromatin, and nuclear moulding. MCPyV was detected in 24 of 53 cases (45%). Staining was strong and diffuse in roughly half of the positive samples. Of the morphologic mimics, one follicular lymphoma showed strong and diffuse staining. In contrast to prior studies, we saw no association between MCPyV status and patient outcomes. Merkel cell polyoma virus IHC is highly specific (97%) for the diagnosis of MCC in our cohort, and can serve as a useful diagnostic tool for distinguishing MCC for morphologic mimics.

LT and SOX9 expression are associated with gene setsthat distinguish Merkel cell polyomavirus (MCPyV)-positive and MCPyV-negative Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is an aggressive malignant neuroendocrine tumour. There are two subsets of MCC, one related to Merkel cell polyomavirus (MCPyV) and the other to ultraviolet radiation (UVR). MCPyV-positive and MCPyV-negative MCCs have been considered to be different tumours, as the former harbour few DNA mutations and are not related to UVR, and the latter usually arise in sun-exposed areas and may be found in conjunction with other keratinocytic tumours, mostly squamous cell carcinomas. Two viral oncoproteins, large T antigen (LT; coded by MCPyV_gp3) and small T antigen (sT; coded by MCPyV_gp4), promote different carcinogenic pathways. To determine which genes are differentially expressed in MCPyV-positive and MCPyV-negative MCC; to describe the mutational burden and the most frequently mutated genes in both MCC subtypes; and to identify the clinical and molecular factors that may be related to patient survival. Ninety-two patients with a diagnosis of MCC were identified from the medical databases of participating centres. To study gene expression, a customized panel of 172 genes was developed. Gene expression profiling was performed with nCounter technology. For mutational studies, a customized panel of 26 genes was designed. Somatic single nucleotide variants (SNVs) were identified following the GATK Best Practices workflow for somatic mutations. The expression of LT enabled the series to be divided into two groups (LT positive, n = 55; LT negative, n = 37). Genes differentially expressed in LT-negative patients were related to epithelial differentiation, especially SOX9, or proliferation and the cell cycle (MYC, CDK6), among others. Congruently, LT displayed lower expression in SOX9-positive patients, and differentially expressed genes in SOX9-positive patients were related to epithelial/squamous differentiation. In LT-positive patients, the mean SNV frequency was 4.3; in LT-negative patients it was 10 (P = 0.03). On multivariate survival analysis, the expression of SNAI1 [hazard ratio (HR) 1.046, 95% confidence interval (CI) 1.007-1.086; P = 0.02] and CDK6 (HR 1.049, 95% CI 1.020-1.080; P = 0.001) were identified as risk factors. Tumours with weak LT expression tend to co-express genes related to squamous differentiation and the cell cycle, and to have a higher mutational burden. These findings are congruent with those of earlier studies.

A review of Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare and aggressive type of metastatic, nonmelanoma skin cancer derived from Merkel cells in the epidermis. MCC can be induced by sun exposure or via Merkel cell polyomavirus (MCV) gene expression. MCV is found in most patients with MCC and is associated with a lower recurrence rate of MCC. MCC has a wide range of clinical presentations that make diagnosis challenging. Histologic examination is performed using unique markers to differentiate it from other diagnoses. This article reviews the pathogenesis, clinical presentation, histopathology, differential diagnosis, and treatment of MCC.

Review of Merkel cell carcinoma with solitary pancreatic metastases mimicking primary neuroendocrine tumor of the pancreas.

Merkel cell carcinoma (MCC) but metastases to the pancreas are very rare. There are only a few cases of isolated metastases of MCC to the pancreas. Because of this rarity, it can be wrongly diagnosed as a neuroendocrine tumor of the pancreas(pNET), especially the poorly differentiated neuroendocrine carcinoma (PNEC) subtype, in which the treatment is vastly different than that of MCC with isolated metastases of the pancreas. An electronic search of the PubMed and google scholar databases was performed to obtain the literature on MCC with pancreatic metastases, using the following search terms: Merkel cell carcinoma, pancreas, and metastases. Results are limited to the following available article types: case reports and case series. We identified 45 cases of MCC with pancreatic metastases from the PubMed and Google Scholar database search and examined their potential relevance. Only 22 cases with isolated pancreatic metastases were taken for review including one case that we encountered. The results from our review of cases of isolated pancreatic metastases of MCC were compared to the characteristics of the poorly differentiated pancreatic neuroendocrine tumor (PNEC). We found the following: (a) MCC with isolated pancreatic metastases occurred at an older age than PNEC and with male gender predominance (b) Most of the metastases occurred within 2years of initial diagnosis of MCC (c) Resection of pancreatic mass was the first line treatment in case of resectable PNECs whereas resection of metastases was infrequently performed in MCC with pancreatic metastases.

MSR9 Exploratory Investigation of Factors Influencing Late Diagnosis in Merkel Cell Carcinoma in the United States

Merkel cell carcinoma (MCC), a rare and aggressive neuroendocrine carcinoma of the skin presents significant diagnostic challenges (i.e., diagnosis time varies 1-54 months, with a median of 3 months) for non-specialist health professionals. The objective of this study was to investigate the factors that may lead to a delayed MCC diagnosis.

A dual institution real-world study of avelumab for advanced Merkel cell carcinoma.

e21514 Background: Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous neoplasm with an increasing incidence rate and poor prognosis. The treatment landscape has changed dramatically over the last half decade, beginning with the 2017 approval of the anti-programmed death-ligand 1 (PD-L1) monoclonal antibody avelumab. Accelerated approval for avelumab was based on data from the JAVELIN Merkel 200 study, which demonstrated an objective response rate (ORR) of 33% in previously treated subjects (≥2L). In the first-line (1L) clinical-trial setting, avelumab was associated with an ORR of 40% and a durable response rate (DRR) of 30%. There are limited data regarding the efficacy of avelumab in the real-world setting. Methods: We performed a Mass General Brigham (MGB) Institutional Review Board-approved retrospective study of patients with advanced MCC. Clinical data regarding the disease course, including diagnosis and treatment, were collected from the Electronic Health Record and stored in a REDCap database. Response category was assigned based on the text of the radiology reports and clinician notes. Analysis was performed in R. Results: 1249 patients with MCC were identified; 260 received systemic therapy; 54 were treated with avelumab (our primary analysis cohort, PAC). Median age of the PAC was 74 years. 80% were male. 83% had an initial ECOG of 0 or 1. 20% were immunosuppressed at the time of MCC diagnosis. The real-world response rate (rwORR) for all patients treated with avelumab was 45.83%. rwORR in the 1L was 53.57% and 35% in the second line and beyond. The median duration of treatment response in the 1L was 518 days and 144 days for ≥2L. Median progression-free survival was 158 days and 95 days, and median overall survival was 553 days and 323 days for 1L and &gt; 2L, respectively. Conclusions: Our study provides important data about the real-world treatment of patients with advanced MCC. The response rate and progression-free survival were consistent with those observed in other real-world studies as well as the clinical trials. While the subjects studied in previously published studies differ from that in MGB cohort, the overall body of literature continues to demonstrate positive outcomes attributable to avelumab monotherapy in both the 1L as well as second-line or beyond and in patients with competent, as well as compromised, immune systems. Limitations of this study include its retrospective nature. Furthermore, given the small sample size, we are limited in making statistical inferences from the current data set and specific results may not be generalizable to all patients with MCC.

SOX11 Is an Effective Discriminatory Marker, When Used in Conjunction With CK20 and TTF1, for Merkel Cell Carcinoma: Comparative Analysis of SOX11, CK20, PAX5, and TTF1 Expression in Merkel Cell Carcinoma and Pulmonary Small Cell Carcinoma.

Distinction between Merkel cell carcinoma (MCC) and pulmonary small cell carcinoma (PSmCC) can be challenging, even with the aid of immunohistochemistry (IHC) analysis of CK20 and TTF1, as these tumors occasionally lack classic immunophenotypes (CK20+/TTF1- in MCC and CK20-/TTF1+ in PSmCC). To evaluate the diagnostic utility of SOX11 and PAX5 IHC for distinguishing MCCs from PSmCCs and compare it with that of CK20 and TTF1 IHC. SOX11, PAX5, CK20, and TTF1 expression (pattern, intensity, and proportion of tumor cells expressing protein) was assessed in 31 primary and 16 metastatic MCCs and 20 primary and 9 metastatic PSmCCs. SOX11 expression was present in all MCCs and was predominantly strong and diffuse. Only 19% of primary and 38% of metastatic MCCs exhibited diffuse PAX5 expression; none exhibited strong immunoreactivity. Strong and diffuse SOX11 expression was seen in less than 25% of primary and metastatic PSmCCs. PAX5 expression was rare in PSmCCs and was mostly weak and focal/patchy. SOX11 expression in at least 26% of tumor cells, with at least moderate intensity, favored the diagnosis of MCC over PSmCC (P < .001). Furthermore, SOX11 expression was more likely than CK20 expression to be strong or diffuse in sentinel lymph node (SLN) metastases of MCC, indicating that SOX11 is superior to CK20 for detecting tumor deposits in SLNs in MCC. Our findings indicate that SOX11 not only is a powerful marker for distinguishing MCCs from PSmCCs, especially when used in conjunction with CK20 and TTF1, but also has utility for screening SLNs in MCC.

Epidemiology of Merkel cell carcinoma in Tuscany (Italy), 2006-2021.

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that still has a poor prognosis. MCC incidence has increased in recent years worldwide. The aim of our study was to perform an epidemiological retrospective study and to evaluate the impact of MCC clinical and pathological features on overall survival (OS) in a specific geographical area. We retrospectively collected 94 pathology reports from 2006 to 2021 that were present in the pathology archives of the University Hospital of Pisa and of the Hospital of Livorno. Laterality was different according to the site, and almost half of the lesions were T1 and nearly half of the patients had a clinical stage III. We reported a dramatic increase in MCC diagnoses in the last 5 years compared with the previous years, with a crude incidence rate of 1,15/100000 inhabitants, almost doubling the last reported data in Italy. Surgical margins status and ulceration were not related to OS. We have noticed some patients with a rapidly progressing disease and others showing a slow disease progression which should prompt the investigation of specific biomarkers or other features that could elucidate this striking difference in progression-free survival and could potentially identify different subtypes of MCC. Considering the generally low incidence of MCC worldwide, larger cohorts would be necessary to validate our data and to obtain a better prognostic stratification.

Combined Merkel Cell Carcinoma with Nodal Presentation: Report of a Case Diagnosed with Excisional but Not Incisional Biopsy and Literature Review.

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine carcinoma (NEC) of the skin. As compared to pure MCCs, combined MCCs are aggressive and exhibit a higher probability of metastasis. A correct diagnosis might be missed, especially when the biopsy sample is too small or too superficial. We report a 79-year-old Taiwanese male who presented with lymphadenopathy suspicious for lymphoma. A nodal biopsy showed metastatic NEC. A skin tumor in the lower back was identified, and an incisional biopsy showed only squamous cell carcinoma (SCC). A subsequent excisional biopsy was performed based on the advice of the senior pathologist because of the presence of metastatic nodal NEC. Finally, a diagnosis of combined MCC and SCC was confirmed. Our literature review identified 13 cases of combined MCC with nodal metastasis as initial presentations, all with an aggressive clinical course. Both the MCC and non-MCC components could be present in the metastatic nodes. Metastases of pure MCC cells were observed in three combined MCCs in sun-protected areas, probably pointing to a distinct pathogenesis. Excision or punch biopsy to include the deep dermal NEC component is recommended as timely diagnosis is mandatory for appropriate management of patients with this rare skin cancer.

Development of Merkel Cell Carcinoma in a Patient Receiving Rituximab

Merkel cell carcinoma (MCC) is a rare, rapidly growing, and aggressive dermatological neoplasm. It is commonly reported in Caucasian ethnicities, and almost 50% of the patients have a concomitant malignancy and are on immunosuppressive chemotherapy. Here, we present a 79-year-old woman with a history of relapsed Stage II, grade III follicular lymphoma, receiving maintenance rituximab infusions. She presented with a raised erythematous papule on her left cheek. An excisional biopsy of the lesion confirmed a diagnosis of Merkel cell carcinoma. After which, she underwent a wider excision with 1-2 cm margins. PET scan did not reveal any FDG-avid uptake lesions that would be concerning for metastatic disease. However, she underwent a sentinel lymph node biopsy which was also negative. Thus, the diagnosis was finalized as Stage I (T1 N0 M0) MCC. There are only two reported cases in literature about the significant progression of Merkel cell carcinoma in patients who coincidentally were receiving rituximab as a part of treatment for another disease. This raises questions for future investigation and research on whether there is a direct association between rituximab use specifically and the rapid growth of MCC.

33904 Early onset Merkel cell carcinoma in patients with XMEN disease

Background: Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer frequently caused by Merkel cell polyomavirus (MCPyV). The median age for MCC diagnosis is 75 years, and MCC is vanishingly rare in patients under 40. We describe 3 patients with X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (XMEN) who developed MCC before age 25. XMEN disease is a rare immunodeficiency associated with lymphoma and caused by mutations in the magnesium transporter 1 (MAGT1) gene. Methods: Retrospective chart review for 3 individuals with MCC and XMEN disease. Results: Patient 1 had a history of recurrent childhood infections and splenomegaly and presented at 14 years of age with metastatic MCC that was treated with high-intensity chemotherapy, radiation therapy, and an autologous stem cell transplant. Patient 2 had a history of chronic EBV viremia and recurrent infections and presented at age 22 with Stage III MCC that was treated with surgical resection and radiotherapy. Patient 3 had a history of thrombocytopenia, splenomegaly, and recurrent infections and developed Stage I MCC at age 24 that was treated with surgical resection and radiotherapy. All three patients had MCPyV positive tumors. The patients are alive and tumor-free 13, 4, and 9 years after diagnosis, respectively. Conclusion: Although immunosuppression increases MCC incidence, XMEN disease is associated with a risk for early onset MCC not observed in other primary immunodeficiencies. The MCPyV positivity and prolonged survival in these 3 cases is also atypical for immunosuppressed patients with MCC.

A Primary Extracutaneous Presentation of Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare aggressive cutaneous neuroendocrine malignancy with a mortality rate of around 33%. The presence of advanced disease at the time of diagnosis is associated with poor prognosis. Twofold etiologies have been described in the pathogenesis of Merkel cell carcinoma: chronic exposure to ultraviolet (UV) light and Merkel cell polyomavirus (MCPvY). MCC usually affects sun-exposed skin areas, and the presence of cutaneous nodules is the hallmark of the disease. However, there have been case reports in the literature where the diagnosis of MCC was made in the absence of any cutaneous findings. We present a case report of Merkel cell carcinoma that is unique in its presentation because of the presence of pulmonary and hepatic nodules and the absence of cutaneous lesions.

Diagnostic Test Accuracy of 18 F-FDG PET or PET/CT in Merkel Cell Carcinoma.

The purpose of the current study was to evaluate the diagnostic accuracies of 18 F-FDG PET or PET/CT for diagnosis of Merkel cell carcinoma (MCC) through a systematic review and meta-analysis. The PubMed, Cochrane database, and EMBASE database, from January 1990 to January 31, 2022, were searched for studies evaluating diagnostic performance of 18 F-FDG PET or PET/CT for MCC. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. Across 9 studies (259 patients), the pooled sensitivity of 18 F-FDG PET or PET/CT was 0.91 (95% confidence interval [CI], 0.85-0.95) and a pooled specificity of 0.93 (95% CI, 0.86-0.97). Likelihood ratio syntheses gave an overall LR+ of 14.0 (95% CI, 6.6-29.6) and LR- of 0.09 (95% CI, 0.05-0.17). The pooled diagnostic odds ratio was 153 (95% CI, 57-416). 18 F-FDG PET/CT showed an excellent performance for diagnosis of MCC. The likelihood ratio scattergram indicated that 18 F-FDG PET or PET/CT is useful for exclusion and confirmation of MCC. Further large multicenter studies would be necessary to substantiate the diagnostic accuracy of 18 F-FDG PET or PET/CT for MCC patients.

Merkel Cell Carcinoma: Case Report and Bibliographic Review

Introduction: Merkel cell carcinoma (MCC) is characterized as a malignant trabecular neoplasm of the skin. The most common sites of lesions are areas frequently exposed to the sun, thus regions such as head, neck and upper limbs. The aim of this study is to report the clinical case of a female patient assisted in a Teaching Hospital in the State of São Paulo, with a lesion in the left gluteal region, unusual to what is found in the literature. Case Report: An 87-year-old female patient, who underwent excisional biopsy of a lesion on her left buttock, with an anatomopathological (AP) diagnosis of MCC, was also submitted to a control image, which showed a new lesion in the lymph node chain, and underwent a new surgical procedure, which was unsuccessful.

Pan-immune-inflammation value independently predicts disease recurrence in patients with Merkel cell carcinoma

PurposeWe aimed to determine whether the pan-immune-inflammation value (PIV) of patients with Merkel cell carcinoma (MCC) at primary diagnosis differs from controls and whether it is associated with disease stage and outcome.MethodsIn this retrospective study, we recruited MCC patients with stage I–III. PIV was calculated from absolute complete blood cell counts obtained within one week at MCC diagnosis as follows: [neutrophils (103/mm3) × platelets (103/mm3) × monocytes (103/mm3)]/lymphocytes (103/mm3). As controls, we studied age–gender-matched cutaneous melanoma (CM, stage I–III) patients and healthy controls (HC). Univariate and multivariate statistics were used.ResultsThe median PIV in MCC patients was significantly increased compared to both CM patients as well as healthy controls. PIV of MCC patients in stage II and III was significantly higher compared to stage I patients. ROC analysis revealed that MCC recurrence was significantly associated with a PIV greater than 372 [p < 0.0001, Youden index 0.58; hazard ratio: 4 (95% confidence interval: 1.7 to 9.2)]. In multivariate analysis, only a PIV greater than 372 and higher MCC stage were determined as independent predictors for disease recurrence.ConclusionWe determined, for the first time, the prognostic ability of the promising blood-based biomarker PIV in MCC patients and observed that PIV is increased in MCC patients in dependence on disease stage and independently predicts MCC recurrence.

NeuN, a DNA-binding neuron-specific protein expressed by Merkel cell carcinoma: analysis of 15 cases.

SummaryAimMerkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma, with an increasing worldwide incidence. It presents as a painless red to purple nodule on sun-exposed skin. MCC is presumed to arise from resident cutaneous Merkel cells. The pathogenesis of MCC is likely multifactorial with immunosuppression, UV-induced skin damage, and Merkel cell polyomavirus contributing to the development. The diagnosis of MCC relies upon characteristic morphologic features and use of immunohistochemical stains. Histologically, the differential diagnosis of Merkel cell carcinoma includes the ‘small round cell’ tumor group, particularly metastatic small cell carcinoma and hematological malignancies. This study investigates the expression of NeuN antibody, which recognizes the protein NeuN, normally present in most neuronal cell types and neuronal tumors, in Merkel cell carcinomas.Methods and resultsFifteen cases of Merkel cell carcinoma (7 men and 7 women; mean age 74 years) were retrieved from the institute database between the years 2011-2020. The immunohistochemical profile was investigated: CK20 (14/14), Neurofilament, (12/12), Synaptophysin (14/14); Chromogranin A (11/13), PAX5 (10/12), TDT (5/12), CK7 (1/14), TTF1 (0/14). Infection by Polyoma virus was detected in 11 of 14 patients. Most tumors showed middle/strong expression of NeuN. No cutaneous structures, or epidermal Merkel cells, showed expression of NeuN. The expression of NeuN was investigated in 17 primary small cell lung carcinomas: 2 cases were positive for Neu-N.ConclusionsAwareness of the staining pattern of Neu-N could aid in diagnosis of Merkel cell carcinoma, avoiding misinterpretation and erroneous diagnosis with other tumors.