Primary Cutaneous Neuroendocrine Tumor of the Vulva: A Case Report.

Primary cutaneous neuroendocrine tumors (CNET) are extremely rare. Only a few cases have been reported so far. CNET have an indolent clinical course and usually present as a single flesh-colored nodule with a predilection for the scalp and trunk in elderly patients. While primary CNET have characteristic histological and immunohistochemical features akin to other low-grade neuroendocrine tumors elsewhere in the body, diagnosing these tumors on skin biopsies can be challenging as they are particularly mistaken for other, more commonly diagnosed, entities. In the current report we present a unique case of primary CNET of the vulva. The clinical presentation will be discussed as well as the histopathologic and immunohistochemical features and most importantly the possible pitfalls in microscopic examination.

Presence of Skin Tissue-Resident Memory T Cells in Human Nonmalignant and Premalignant Melanocytic Skin Lesions and in Melanoma.

ABSTRACT: The infiltration of tissue-resident memory (TRM) cells in melanoma correlates with improved survival, suggesting an important role for TRM cells in immunity against melanoma. However, little is known about the presence of TRM cells in nonmalignant and premalignant melanocytic lesions. This study aimed to evaluate the presence of TRM cells in human skin melanocytic lesions, representing the spectrum from healthy skin to metastatic melanoma. FFPE sections from healthy skin, sun-exposed skin, benign nevi, lentigo maligna (LM), primary LM melanoma, and primary cutaneous and metastatic melanoma were analyzed by immunohistochemistry. The number of infiltrating cells expressing TRM-associated markers, CD3, CD4, CD8, CD69, CD103, and CD49a, was quantified by digital analyses. Multiplex immunofluorescence was performed to analyze coexpression of TRM cell markers. More T cells and CD69+ cells were found in melanoma lesions, as compared with healthy skin and nevi. CD103+ and CD49a+ cell numbers did not significantly differ. More importantly, no differences were seen in expression of all markers between healthy skin and benign nevi. Similar results, except for CD69, were observed in LM melanoma, as compared with LM and sun-exposed skin. Interestingly, multiplex immunofluorescence showed that nevi tissues have comparable CD103+ T cell numbers with healthy skin but comprise more CD103+ CD8+ cells. Expression of TRM cell markers is significantly increased in melanoma, as compared with nonmalignant skin. Our data also show that TRM cells are not abundantly present already in premalignant tissues. Further studies on the specificity of TRM cells for melanocyte/melanoma antigens may reveal their significance in cancer immunosurveillance.

Limited impact of COVID-19-related diagnostic delay on cutaneous melanoma and squamous cell carcinoma tumour characteristics: a nationwide pathology registry analysis.

BACKGROUND: The COVID-19 pandemic reduced the number of skin cancer diagnoses, potentially causing a progression to unfavourable tumour stages. OBJECTIVES: To identify the impact of delayed diagnostics on primary invasive melanoma and cutaneous squamous cell carcinoma (cSCC) by comparing tumour (pT) stage, Breslow thickness and invasion depth from before to after the first and second lockdown periods. METHODS: In this population-based cohort study, histopathology reports registered between 1 January 2018 and 22 July 2021 were obtained from the nationwide histopathology registry in the Netherlands. The Breslow thickness of melanomas, invasion depth of cSCCs, and pT stage for both tumour types were compared across five time periods: (i) pre-COVID, (ii) first lockdown, (iii) between first and second lockdowns, (iv) second lockdown and (v) after second lockdown. Breslow thickness was compared using an independent t-test. pT-stage groups were compared using a χ2 -test. Outcomes were corrected for multiple testing using the false discovery rate. RESULTS: In total, 20 434 primary invasive melanomas and 68 832 cSCCs were included in this study. The mean primary melanoma Breslow thickness of the prepandemic era (period i) and the following time periods (ii-v) showed no significant difference. A small shift was found towards unfavourable pT stages during the first lockdown compared with the pre-COVID period: pT1 52·3% vs. 58·6%, pT2 18·9% vs. 17·8%, pT3 13·2% vs. 11·0%, pT4 9·1% vs. 7·3% (P = 0·001). No relevant changes were seen in subsequent periods. No significant change in pT stage distribution was observed between the pre-COVID (i) and COVID-affected periods (ii-v) for cSCCs. CONCLUSIONS: To date, the diagnostic delay caused by COVID-19 has not resulted in relatively more unfavourable primary tumour characteristics of melanoma or cSCC. Follow-up studies in the coming years are needed to identify a potential impact on staging distribution and survival in the long term.

Familial multiple discoid fibromas: a look-alike of Birt-Hogg-Dubé syndrome not linked to the FLCN locus.

BACKGROUND: Previously, we proposed that familial multiple trichodiscomas (OMIM 190340) is distinct from Birt-Hogg-Dubé syndrome (BHD) (OMIM #135150). BHD is characterized by multiple fibrofolliculomas/trichodiscomas, lung cysts, pneumothorax, and renal cell cancer. Germline FLCN mutations can be detected in most but not all BHD families. OBJECTIVE: We sought to evaluate familial multiple trichodiscomas at a clinical and genetic level. We now renamed this condition "familial multiple discoid fibromas" (FMDF) to emphasize the distinction from BHD. METHODS: In 8 additional families with an autosomal dominant pattern of multiple discoid fibromas we assessed the clinical findings and the histopathological features of skin lesions. FLCN germline mutation analysis was completed in 7 families. In two of these families segregation analysis was performed using polymorphic DNA markers in and around the FLCN locus. RESULTS: The clinical findings in FMDF are different from those in BHD with early onset of skin lesions, prominent involvement of the pinnae, and discoid fibromas without the follicular epithelial component characteristic of the fibrofolliculoma/trichodiscoma spectrum of BHD. In addition, there were no evident pulmonary or renal complications. In none of the families were pathogenic FLCN germline mutations identified. Using segregation analysis we could exclude involvement of the FLCN locus in the two kindreds tested. LIMITATIONS: The prevalence of FMDF is presently unknown. The underlying gene defect has not yet been identified. CONCLUSIONS: FMDF is clinically distinct from BHD and is not linked to the FLCN locus.

Russell bodies in a skin biopsy: a case report.

INTRODUCTION: The presence of eosinophilic bodies in a skin biopsy can be found in a variety of situations and this may present a challenge to the pathologist. The differential diagnosis of these eosinophilic structures include microorganisms such as histoplasmosis or cryptococcosis, fungi, Michaelis-Gutmann bodies, deposits of amyloid or immunoglobulins, colloid bodies or elastic bodies. CASE PRESENTATION: During a routine examination of a skin biopsy with actinic keratosis taken from the cheek of a 61-year-old man, clusters of eosinophilic bodies were seen within an inflammatory infiltrate in the dermis, both intracytoplasmic and extracellular. Using additional immunohistochemical staining, these structures were identified as polyclonal Russell bodies. CONCLUSION: The differential diagnosis of intracytoplasmic eosinophilic structures in a skin biopsy includes Russell bodies, an uncommon finding that may be associated with chronic inflammatory conditions.

Birt-Hogg-Dubé syndrome: clinical and genetic studies of 20 families.

Birt-Hogg-Dubé syndrome (BHD) is an autosomal-dominant genodermatosis characterized by skin fibrofolliculomas and an increased risk of spontaneous pneumothorax, renal and possibly other tumors. A causative gene (FLCN) on chromosome 17p has recently been identified. We here report clinical and genetic studies of 20 BHD families ascertained by the presence of multiple fibrofolliculomas or trichodiscomas in the proband. Pathogenic FLCN germline mutations were found in 11 (69%) of 16 probands tested and in 14 family members. Six different FLCN germline mutations were detected, four of which have not been reported previously. The clinical features were variable. None and less than 10 skin lesions were observed in two mutation carriers at the age of 67 and 29 years, respectively. Spontaneous pneumothorax was reported in four and renal carcinoma of mixed histological types in two of 36 BHD-affected individuals and/or FLCN mutation carriers. Both the prevalence of spontaneous pneumothorax and renal tumors appeared to be relatively low compared with previously reported data. Various other extracutaneous tumors were observed in 11 of 36 BHD-affected individuals and/or FLCN mutation carriers. This study of the second largest cohort to date contributes to the expanding data on the variable phenotype and underlying gene defects in BHD.