Melanoma metastático de sítio primário indeterminado

relato de caso

Abstract

Cutaneous melanoma is the most common skin cancer. It is a malignant neoplasm classified into four subtypes. In cases where the primary site of the lesion is undetermined, the immunohistochemistry of the metastatic lesions helps in the diagnosis, and it is essential to rule out the possibility of clear cell sarcoma. Clear cell sarcoma is a rare malignant soft tissue tumor that has histological, cytological, and immunohistochemical similarity to melanoma. The aim of the study is to report the case of a 47-year-old patient sought care at Hospital Naval Marcílio Dias in May 2020 due to severe headache and neurological symptoms. Computed tomography showed metastatic lesions in the brain, pancreas and adrenal. The patient underwent a biopsy whose report was compatible with metastatic melanoma and could not rule out clear cell sarcoma. A BRAF gene mutation search and a negative chromosomal study for clear cell sarcoma were performed, defining the
diagnosis of melanoma. The proposed treatment was performed, but the patient died. It was argued that tumor differentiation occurs through the translocation test (12;22)(q13;12) that generates the fusion of the EWS gene with ATF1, which is present in 75% of cases of clear cell sarcoma, or by the fusion of EWS with CREB1 (2q13 gene) found in a clear cell sarcoma subtype with a preference for the gastrointestinal tract. In concluded that there is a need to rule out the diagnosis of clear cell sarcoma in patients with metastatic melanoma of an undetermined primary site due to the similarities found, but with different treatment and prognosis.