Abstract Viruses have been frequently identified in several human neoplasms, but the etiological role of these viruses in some tumors is still a matter of controversy. Polyomaviruses stand out among the main viruses with oncogenic capacity, specifically the Merkel cell polyomavirus (MCPyV). Recent revisions in the taxonomy of polyomaviruses have divided the Polyomaviridae family into six genera, including 117 species, with a total of 14 currently known human-infecting species. Although the oncogenicity of polyomaviruses has been widely reported in the literature since 1950, the first description of a polyomavirus as an etiological agent of a neoplasm in humans was made only in 2008 with the description of MCPyV, present in approximately 80% of cases of Merkel cell carcinoma (MCC), with the integration of its genome to that of the tumor cells and tumor-specific mutations, and it is considered the etiological agent of this neoplasm since then. MCPyV has also been detected in keratinocyte carcinomas, such as basal cell carcinoma and squamous cell carcinoma of the skin in individuals with and without immunosuppression. Data on the occurrence of oncogenic viruses potentially involved in oncogenesis, which cause persistence and tissue injury, related to the Merkel cell polyomavirus are still scarce, and the hypothesis that the Merkel cell polyomavirus may play a relevant role in the genesis of other cutaneous carcinomas in addition to MCC remains debatable. Therefore, the present study proposes to explore the current knowledge about the presence of MCPyV in keratinocyte carcinomas.

RESUMO A paniculite pancreática (PP) é uma manifestação rara de doença pancreática que acomete o tecido adiposo subcutâneo. Relatamos dois casos dessa entidade: uma paciente do sexo feminino, 37 anos, portadora de lúpus eritematoso sistêmico (LES) e uma idosa com doença de Crohn. Ambas manifestações são doenças inflamatórias crônicas autoimunes raramente relacionadas com o quadro de pancreatite aguda e que culminaram em PP. Também fizemos uma breve revisão sobre tratamento, diagnóstico e morfologia das lesões, bem como da fisiopatologia da doença. Destacamos a importância da imuno-histoquímica e da análise histopatológica de biópsias da lesão como ferramentas diagnósticas.

ABSTRACT Pancreatic panniculitis (PP) is a rare manifestation of pancreatic disease, involving subcutaneous adipose tissue. We report two cases of this entity: a 37-year-old female patient with systemic lupus erythematosus (SLE) and an elderly woman with Crohn’s disease. These are two chronic autoimmune inflammatory diseases that can be uncommonly related to acute pancreatitis and that culminates in PP. We also provide a brief review of the treatment, diagnosis and morphology of the lesions, as well as the pathophysiology of the disease. The importance of histopathological analysis of lesion biopsies is highlighted as an important diagnostic tool.

RESUMEN La paniculitis pancreática (PP) es una manifestación rara de enfermedad pancreática que afecta el tejido graso subcutáneo. Reportamos dos casos de esa entidad: una paciente del sexo femenino, 37 años, con lupus eritematoso sistémico (LES), y una anciana con enfermedad de Crohn. Ambas manifestaciones son enfermedades crónicas autoinmunes raramente relacionadas con el cuadro de pancreatitis aguda y que culminaron en PP. También hicimos una breve revisión acerca de tratamiento, diagnóstico y morfología de las lesiones, así como fisiopatología de la enfermedad. Se resalta la importancia de la inmunohistoquímica y del análisis histopatológico de biopsias de la lesión como herramientas diagnósticas.

RESUMO A micose fungoide intersticial (MFI) é uma variante rara da micose fungoide, um linfoma cutâneo de células T não Hodgkin. É caracterizada por um infiltrado dérmico intersticial de linfócitos e histiócitos entre feixes de colágeno. Relatamos o caso de um paciente de 54 anos com máculas hipocrômicas pruriginosas nos braços e antebraços com diagnóstico de MFI. Atenção especial foi dada às características anatomopatológicas que diferenciam essa entidade de seus diagnósticos diferenciais, como morfeia inflamatória, granuloma anular intersticial e outras variantes da própria micose fungoide. Apresentamos também uma revisão da literatura sobre a classificação da MFI.

ABSTRACT Interstitial mycosis fungoides (IMF) is a rare variant of mycosis fungoides, a cutaneous T-cell non-Hodgkin’s lymphoma. It is characterized by an interstitial dermal infiltrate of lymphocytes and histiocytes between collagen bundles. We report the case of a 54-year-old patient with pruritic hypochromic macules on the arms and forearms diagnosed with IMF. Special attention was given to the anatomopathological features that differentiate this entity from its differential diagnoses, such as inflammatory morphea, interstitial annular granuloma, and other variants of the mycosis fungoides itself. We also present a review of the literature on the classification of the IMF.

RESUMEN La micosis fungoide intersticial (MFI) es una variante poco común de la micosis fungoide, un linfoma cutáneo de células T no Hodgkin. Se caracteriza por un infiltrado dérmico intersticial de linfocitos e histiocitos entre haces de colágeno. Presentamos el caso de un paciente de 54 años con máculas hipocrómicas pruriginosas en brazos y antebrazos diagnosticado de MFI. Se prestó especial atención a las características anatomopatológicas que diferencian a esta entidad de sus diagnósticos diferenciales, como morfea inflamatoria, granuloma anular intersticial y otras variantes de la propia micosis fungoide. También presentamos una revisión de la literatura sobre la clasificación de la MFI.

RESUMO Adenodermatofibroma hemossiderótico é uma lesão recentemente conhecida, caracterizada por um nódulo dérmico com estruturas císticas de uma glândula apócrina, circundado por um estroma do tipo dermatofibroma com macrófagos hemossideróticos. Apresentamos o primeiro relato de caso dessa entidade no Brasil junto a imagens representativas, além de uma revisão do assunto e discussões sobre a origem apócrina dessa lesão.

ABSTRACT Hemosiderotic adenodermatofibroma is a recently recognized lesion, characterized by a dermal nodule with cystic structures of an apocrine gland, surrounded by a dermatofibroma-like stroma with hemosiderotic macrophages. We present the first case report of this entity in Brazil together with representative images, in addition to a review on the subject and discussion about the apocrine origin of this lesion.

RESUMEN El dermatoadenofibroma hemosiderótico es una lesión recientemente descrita, caracterizada por un nódulo dérmico con estructuras quísticas de una glándula apocrina, rodeado por un estroma del tipo dermatofibroma con macrófagos hemosideróticos. Presentamos el primer reporte de caso de esa entidad en Brasil, junto a imágenes representativas, además de una revisión del tema y discusiones acerca del origen apocrina de esa lesión.

Abstract: Lichen planopilaris is a disease that appears with lymphocytic cicatricial alopecia. It is considered a follicular variant of lichen planus. The examination of affected areas shows alopecia with perifollicular erythema and scaling, revealing a predilection for hair follicles. The involvement of children is uncommon, with few reports in this population in the literature. This study presents a clinical case of a male patient of 15 years of age with characteristic lesions of lichen planopilaris.

Abstract Merkel cell carcinoma is an uncommon neuroendocrine carcinoma with a rising incidence and an aggressive behavior. It predominantly occurs in older patients, with onset occurring at a mean age of 75-80 years. Recognized risk factors are ultraviolet sunlight exposure, immunosuppression, and, more recently, Merkel cell polyomavirus. We report a case of Merkel cell carcinoma in a young HIV positive patient with Merkel Cell polyomavirus detected in the tumor.

Abstract: The diagnosis of cutaneous melanoma in situ, considered to have excellent prognosis, has been increasingly frequent, with rare isolated reports of cutaneous melanoma in situ presenting recurrence, metastasis, and death. No specific study is found in the literature about these lesions of unexpected behavior. We describe the demographic and histopathological findings of 448 cases of cutaneous melanoma in situ in 369 patients, emphasizing the prognostic criteria of those with unfavorable outcomes, corresponding to 9 cases in which regression had no significant role. Adnexotropism was found in 44.5% of cases. The study of early lesions would allow clinicians to have a better understanding of the evolutionary processes of the disease.

Abstract We describe a fifty-six-year old, Afro-descendent female patient showing dystrophy of her twenty nails and hyperchromic, asymptomatic macule on her face. Histopathological examination of the macule showed vacuolization of the basal layer, melanophages in the superficial dermis and lymphoplasmocytic inflammatory infiltrate. Nail biopsy revealed orthokeratotic hyperkeratosis and lichenoid inflammatory infiltrate. Lichen planus pigmentosus is an uncommon variety of lichen planus. It is characterized by typical hyperpigmented macules on the face and neck. Nail changes might be present in 10% of lichen planus cases, but no associations with lichen planus pigmentosus have been described. We report a case of lichen planus in twenty nails associated with lichen planus pigmentosus on the patient's face.

RESUMO O diagnóstico de lesões melanocíticas pode ser desafiador, e o estudo imuno-histoquímico é uma ferramenta valiosa para os dermatopatologistas. Relatamos dois casos inicialmente diagnosticados como melanoma in situ, avaliando os achados histopatológicos e imuno-histoquímicos e os casos publicados na literatura com resultados semelhantes. Ressaltamos a importância da correlação clinicopatológica na avaliação das lesões com danos na interface e nos "ninhos pseudomelanocíticos", que podem simular melanoma in situ. Destacamos também a importância da utilização de um painel de imuno-histoquímica, além do Melan-A, no estudo dessas lesões.

ABSTRACT The diagnosis of melanocytic lesions can be challenging and immunohistochemical study is a valuable tool for dermatopathologists. We report two cases initially simulating melanoma in situ, reviewing the histopathological and immunohistochemical findings and the cases published in the literature with similar findings/results. We emphasize the importance of clinicopathological correlation in the evaluation of lesions with interface changes and in the "pseudomelanocytic nests", which may simulate melanoma in situ. We also highlight the importance of using a immunohistochemistry panel in addition to Melan-A, in the study of these lesions.

FUNDAMENTOS: A síndrome de Sweet corresponde a um conjunto de alterações cutâneas, sistêmicas e histopatológicas como resposta a diversos estímulos, semelhantes ao eritema nodoso, ao eritema multiforme e à vasculite leucocitoclásica. São descritas condições associadas como infecção, gravidez, uso de drogas e malignidades. OBJETIVOS: Avaliar as alterações clínicas e histopatológicas da síndrome, relacionando-a a outras condições. MÉTODO: Estudo retrospectivo de 73 casos com avaliação microscópica de lesões cutâneas, dados clínicos e laboratoriais. RESULTADOS: Houve predomínio de mulheres (83,0%), brancas (49,2%), entre a quarta e a sexta décadas de vida (73,8%). Placas eritematosas (76,9%), pápulas (43,0%), pseudovesiculação (PV) (38,4%) e lesões em alvo (18,5%) foram as principais alterações. Entre as condições associadas, infecções de vias aéreas (15,4%) e uso de drogas (10,8%) foram as mais frequentes. Outras associações, representadas por um caso cada, foram: linfoma de Hodgkin, gravidez, colite ulcerativa, policitemia vera e lúpus eritematoso em paciente com Aids. Neutrófilos com leucocitoclasia (98,6%), degeneração do colágeno (87,7%), edema (74,0%) e PV (38,4%) foram os principais achados microscópicos. Eosinófilos estiveram presentes (41,1%) de raros a abundantes e, em geral, não relacionados ao uso de drogas. O infiltrado inflamatório atingiu a derme profunda em 47,9% das vezes e encontrou-se paniculite em 80,0% dos casos nos quais a hipoderme estava representada (10 casos). CONCLUSÕES: Os achados, de modo geral, coincidem com os da literatura, destacando-se: frequente participação de eosinófilos sem correlação com a ingestão de medicamentos, paniculite e rara associação com linfoma de Hodgkin, sendo este o quinto relato de tal ocorrência, segundo o conhecimento dos autores.

BACKGROUND: Sweet's syndrome refers to a set of cutaneous, systemic and histopathological alterations that occur in response to different stimuli, in a similar way to that occurring in erythema nodosum, erythema multiforme and leukocytoclastic vasculitis. The syndrome has been described in association with conditions such as infections, pregnancy, the use of certain medications and malignancy. OBJECTIVES: To evaluate the clinical and histopathological alterations occurring in this syndrome and to assess the association between these alterations and other conditions. METHODS: A retrospective study of 73 cases was conducted, evaluating data on the microscopic examination of skin lesions, as well as clinical and laboratory data. RESULTS: The majority of the patients were female (83.0%), white (49.2%) and between 30 and 60 years of age (73.8%). The principal alterations found were: erythymatous plaques (76.9%), papules (43.0%), pseudo-vesiculation (PV) (38.4%) and target lesions (18.5%). With respect to the associated conditions, upper respiratory tract infections (15.4%) and the use of medication (10.8%) were the most common. Other associations, albeit represented by only one case each, were: Hodgkin's lymphoma, pregnancy, ulcerative colitis, polycythemia vera and lupus erythematosus in a patient with acquired immune deficiency syndrome (AIDS). The principal microscopic findings were: neutrophils with leukocytoclasia (98.6%), collagen degeneration (87.7%), edema (74.0%) and PV (38.4%). The presence of eosinophils (41.1%) ranged from rare to abundant and was usually unrelated to the use of medication. Inflammatory infiltrate reached the deep epidermal layer in 47.9% of cases and panniculitis was found in 80.0% of cases in which the hypodermis was affected (10 cases). CONCLUSIONS: In general, these findings are in agreement with results published in the literature, emphasizing the frequent finding of eosinophils unrelated to drug use, panniculitis and the rare association with Hodgkin's lymphoma. This is the fifth report of an association between Sweet's syndrome and Hodgkin's disease.

INTRODUÇÃO: O diagnóstico de melanomas cutâneos finos (MCF) é cada vez mais freqüente. Essas lesões, inicialmente associadas a excelente prognóstico, têm apresentado recidiva ou metástases e, às vezes, óbito. Muitas variáveis têm sido estudadas e, embora nenhuma delas tenha esclarecido tal comportamento, a regressão e seu possível impacto negativo têm merecido atenção. A regressão tardia é referida pelos autores como de maior relevância no prognóstico. OBJETIVO: Correlacionar a espessura máxima da área de regressão dos MCFs com o tempo de sobrevida livre de doença. MATERIAL E MÉTODO: Estudo retrospectivo de 84 casos de MCF. Foram utilizados os critérios de Kang et al.(18) para identificação e classificação evolutiva (recente, intermediária e tardia) da regressão. RESULTADOS: Nos 84 MCFs estudados, regressão (em qualquer fase) foi observada em 70 (83,3%), sendo 30 casos (35,7%) com regressão tardia. A medida máxima da regressão variou entre 0,16 e 1,53 mm. O tempo de sobrevida livre de doença variou entre 17 dias e 108 meses. Cinco casos (5,9%) evoluíram de forma desfavorável, dos quais três eram melanomas in situ (MIS). Não houve correlação entre as variáveis estudadas (p > 0,05). DISCUSSÃO: O significado da regressão sobre o comportamento de MCF é controverso, provavelmente devido a diferentes metodologias utilizadas nos poucos estudos realizados sobre o tema e à grande variabilidade no tamanho e na composição das amostras. Não há consenso na literatura sobre um sistema padronizado de medição da regressão, o que explica, em parte, os resultados controversos obtidos até o momento. CONCLUSÃO: Não ficou demonstrada relação entre a espessura da regressão nos melanomas finos e o tempo de sobrevida livre de doença. Estudos futuros, com amostra maior, poderão contribuir para a elucidação da natureza deste fenômeno.

BACKGROUND: The diagnosis of thin cutaneous malignant melanomas has been increasingly more frequent. These lesions, initially associated with excellent prognosis, have presented recurrence or metastases and sometimes have been fatal. Many variables have been studied and, although none of them has explained this behaviour, regression and its possible negative impact have been focused on recently. According to some authors, late regression bears major relevance in the prognosis. OBJECTIVE: To correlate the maximum regression thickness of thin cutaneous malignant melanomas with disease-free survival time. MATERIALS AND METHOD: Retrospective study of 84 cases of thin cutaneous malignant melanomas. The criteria of Kang et al. (1993) for identification and evolutionary classification (early, intermediate and late) of the regression were applied. RESULTS: Regression (in any phase) was observed in 70 out of 84 thin cutaneous malignant melanomas (83.3%), and 30 cases (35.7%) showed late regression. The maximum regression thickness measurement ranged from 0.16 to 1.53 mm. Disease-free survival time ranged from 17 days to 108 months. Five cases (5.9%) had an unfavorable outcome, from which three were in situ melanomas. There was no correlation between the studied variables (p > 0.05). DISCUSSION: The meaning of regression in thin cutaneous malignant melanomas is controversial, probably due to the different methods applied in the few studies carried out about the subject and the wide variety of size and composition of the samples. There is no medical consensus as to a standardized regression measurement system, which partially explains the controversial results obtained to date. CONCLUSIONS: There was no statistical correlation between regression thickness in thick cutaneous melanomas and disease-free survival time (p > 0.05). Future studies with wider samples may contribute to a better understanding of this phenomenon.