O queratoacantoma (QA), apesar de frequente na prática diária, é um tumor que gera questionamentos. O aspecto mais intrigante associa-se à sua posição no limite entre malignidade e benignidade. A abordagem do tumor, bem como sua classificação, é controversa. Na definição da conduta, é importante levar em conta o potencial de transformação para carcinoma espinocelular. Desse modo, a excisão cirúrgica é a terapia de escolha, sempre que possível. Algumas situações merecem atenção adicional, como a imunossupressão associada. Neste artigo, relatamos um caso de QA gigante em um paciente com síndrome da imunodeficiência adquirida tratado com cirurgia micrográfica de Mohs.

Keywords: Ceratoacantoma; Retalhos Cirúrgicos; Neoplasias Nasais; Neoplasias Cutâneas; Cirurgia de Mohs; Síndrome de Imunodeficiência Adquirida; HIV; Imunossupressão

Sarcomas são neoplasias mesenquimais malignas, raras, que acometem, principalmente, crianças e adolescentes. O rabdomiossarcoma, subtipo oriundo da musculatura esquelética, é condição incomum em adultos, acometendo sítios de localização não habitual, crescimento rápido e de difícil tratamento. Apresenta-se caso de adulto jovem com nodulação em lóbulo auricular esquerdo, cuja análise histopatológica e imuno-histoquímica confirmou tratar-se de rabdomiossarcoma alveolar, o qual foi conduzido em conjunto com a Oncologia.

Keywords: Rabdomiossarcoma Alveolar; Miogenina; Desmina; Excisão de Linfonodo

Cutaneous diffuse large B-cell lymphoma, leg type, is a rare, aggressive, and poorly prognostic neoplasm. It corresponds to 10-20% of cutaneous B-cell lymphomas and mainly affects the lower limbs of older women. We report the case of an 81-year-old woman with painful, fast-growing nodules and tumors in her left leg. Histopathological and immunohistochemical findings, associated with the absence of extra-cutaneous involvement during staging, concluded the diagnosis of cutaneous diffuse large B-cell lymphoma, leg type. The rarity of this limphoma, its typical clinic and epidemiology, and the excellent response to treatment motivated this report.

Keywords: Immunohistochemistry; Diffuse; Lymphoma non Hodgkin; Lymphoma large B-cell, Neoplasms; Therapeutics

Primary cutaneous B-cell lymphomas are non-Hodgkin lymphomas presenting only in the skin and represent 25% of all primary cutaneous lymphomas. Based on their clinical behavior, they are classified into indolent and intermediate forms. Treatment of indolent forms includes surgery, radiotherapy, and, in extensive disease, rituximab. We report a case of a 57-year-old woman with a single nodule in the left arm treated with surgical excision with 5-mm security margins, without relapse after 36 months. Surgery is a therapeutic option in these lymphomas without compromising disease-free survival.

Keywords: Lymphoma B-Cell; Lymphoma B-Cell marginal zone; Lymphoma non-Hodgkin; Surgical oncology

A narrative review was performed to clarify the ontogenesis of Merkel-cell carcinoma. It is hypothesized that the cells are derived from the embryonic neural crest, skin stem cells, epithelial cells, pre-/pro-B cells, dermal fibroblasts, or metastatic cells from other types of carcinomas. The influence of epigenetics was also considered. Methodologically, to prepare the summary articles were selected from the PubMed and SciELO databases and cited references. The results suggest that it is more likely that Merkel-cell carcinoma has multiple origins, possibly from poorly differentiated cells.

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A narrative review was performed to clarify the ontogenesis of Merkel-cell carcinoma. It is hypothesized that the cells are derived from the embryonic neural crest, skin stem cells, epithelial cells, pre-/pro-B cells, dermal fibroblasts, or metastatic