The prognostic role of PD-L1 expression and the presence of polyomavirus in Merkel cell carcinoma cases.

BACKGROUND: Merkel cell carcinoma (MCC) comprises a rare malignant primary skin tumor presenting neuroendocrine differentiation. Recently, agents blocking the programmed cell death protein 1 and programmed cell death protein ligand 1 pathway (PD-1/PD-L1) have demonstrated objective and durable tumor regressions in patients presenting advanced MCC. This study aimed to describe the sociodemographic, clinical, and histopathological characteristics of MCC patients, also assessing the prevalence of PD-L1 expression and Merkel cell Polyomavirus (MCPyV), as well as their prognostic roles. METHODS: Data from patients diagnosed with MCC between 1996 and 2019 at a reference cancer center in Rio de Janeiro, southeastern Brazil, were evaluated in a retrospective study. Tumor samples were tested for MCPyV and PD-L1 employing immunohistochemistry. Survival analyses were carried out employing the Kaplan-Meier method and curves were compared using the log-rank test. A multiple semiparametric Cox model was used. Values p < 0.05 were considered significant. RESULTS: A total of 65 patients were included in the study, with a mean age at diagnosis of 72 (standard deviation 13.9). A total of 56.9% (37/65) of the patients were male, 86.2% (56/65) were white, and 56.9% (37/64) were illiterate or with incomplete elementary school. MCPyV immunohistochemistry was positive in 29 cases (44.6%) and PD-L1 positivity was ≥ 1% in 42 cases (64.6%). Significant associations between MCPyV and PD-L1 expression ≥ 1% (p = 0.003) and PD-L1 expression ≥ 5% (p = 0.005) were noted. Concerning the multivariate analysis, only education level and advanced MCC stage indicated statistically significant worse progression-free survival. Regarding overall survival (OS), being male, education level and advanced stage comprised risk factors. The estimated OS at 60 months for stages I to III was of 48.9% and for stage IV, 8.9%. CONCLUSIONS: This is the first large Brazilian cohort to assess the prevalence of MCPyV in MCC tumors, as well as PD-L1 expression and their associations. No correlations were noted between MCPyV infection or PD-L1 expression and survival rates.

Reflectance confocal microscopy - Consensus terminology glossary in Brazilian Portuguese for normal skin, melanocytic and non-melanocytic lesions

Abstract Background: Currently, there is no uniform and official terminology in Portuguese for reflectance confocal microscopy analysis, despite the increasing number of Brazilian dermatologists using this new tool. Objective: To present the terminology in Brazilian Portuguese for the description of reflectance confocal microscopy and establish the first Brazilian consensus on terms related to normal skin and cutaneous tumors. Methods: 10 Brazilian specialists from different institutions and states of Brazil were selected to evaluate the best corresponding terms in Portuguese for normal skin, melanocytic and non-melanocytic tumors. The terms used were translated from international consensuses in the English language. The modified Delphi method was used to create the consensus in 3 steps. Results: The terms considered the most appropriate in the Portuguese language to describe the findings of normal skin, melanocytic and non-melanocytic lesions in the reflectance confocal microscopy analysis were presented. Study limitations: The limitations of the present study include the number of participants and limited regional representation (only two of the five Brazilian regions were represented). Conclusion: This Brazilian consensus represents an opportunity for dermatologists and physicians specializing in cutaneous oncology to become familiar with reflectance confocal microscopy, propagating the technique in clinical and research environments to stimulate national and international publications on this subject.

Merkel cell carcinoma: epidemiology, clinical features, diagnosis and treatment of a rare disease

Abstract Merkel cell carcinoma is a rare skin cancer with neuroendocrine differentiation. The risk factors include sun exposure, advanced age, immunosuppression (such as transplant recipients, patients with lymphoproliferative neoplasms, or patients with HIV), and Merkel cell polyomavirus infection. Clinically, Merkel cell carcinoma appears as a cutaneous or subcutaneous plaque or nodule, but this tumor diagnosis is rarely made clinically. Therefore, histopathology and immunohistochemistry are usually necessary. Primary tumors without evidence of metastases are treated with complete surgical excision and appropriate surgical margins. The presence of occult metastasis in a lymph node is frequent and a sentinel lymph node biopsy should be performed. Postoperative adjuvant radiotherapy increases local tumor control. Recently, agents that block the PD-1/PD-L1 pathway have shown objective and durable tumor regression in patients with advanced solid malignancies. The first anti-PD-L1 antibody used in patients with Merkel cell carcinoma was avelumab, but pembrolizumab and nivolumab have also shown efficacy. This article describes the current state of knowledge of the epidemiology, diagnosis, and staging of Merkel cell carcinoma, as well as new strategies for its systemic treatment.

Collision tumor: pigmented Bowen's disease and seborrheic keratosis

Abstract: Bowen's disease is a type of squamous cell carcinoma in situ of the skin. The pigmented form is rare and represents less than 2% of cases. We report a case of a 74-year-old black man with a blackened and asymptomatic leg injury for about 6 months. Clinically, and under dermatoscopy, the injury was suggestive of melanoma or melanoacanthoma, and a definitive diagnosis was made by histopathological examination.

Paraneoplastic Sweet's syndrome

Abstract: Sweet's syndrome is a rare dermatosis with little-known pathogenesis, associated with some clinical conditions such as infections, autoimmune diseases, inflammatory bowel diseases, vaccination, medications and neoplasms. Hematologic malignancies are the diseases most related to paraneoplastic Sweet's syndrome, but this clinical entity can also be found occasionally in some solid tumors, including genitourinary tract tumors. We report a rare case of paraneoplastic Sweet's syndrome associated with the diagnosis of cervical cancer.

Histopathological diagnosis of small melanocytic lesions suspicious for malignant melanoma

Abstract The concern about malignant skin neoplasms leads to the excision of smaller lesions. This study on small melanocytic lesions aims to evaluate the range of possible histopathological diagnoses, describe histopathological aspects, and assess the usefulness of serial histological sections. We performed a cross-sectional descriptive histopathological study examining 76 pigmented skin lesions up to 6 mm in diameter. Histopathological diagnoses included atypical melanocytic nevi (n=38), common melanocytic nevi (n=18), atypical lentiginous melanocytic hyperplasia with architectural features of atypical melanocytic nevi (n=7), lentigo simplex (n=2), and malignant melanoma (n=1). Ten cases were non-diagnostic. Cytological atypia was not an exclusive finding of atypical lesions. Examination of serial sections did not change histopathological impression. Early detection of malignant melanoma is important, but clinical and dermoscopy exams may be leading to the resection of a great number of benign lesions. Strict attention to histopathological criteria results in a large number of non-diagnostic cases.