Dados do Trabalho

Título

RARE EXTENSIVE DESMOPLASTIC VEGETANT MELANOMA IN CERVICO-THORACIC TRANSITION: CASE REPORT

Apresentação do caso

An 85-year-old woman came to the oncology service reporting a vegetating lesion in the right clavicular fossa, with 4 years of evolution and sharp growth for a year. On examination, a lesion measuring 7cm in the longest axis, irregular edges, suppurative, bleeding, and foul odor. Absence of cervical and axillary lymph node enlargement. Extensive soft tissue tumor resection was performed in the right cervicothoracic transition. Infiltrating muscle fascia and invading the right supraclavicular fossa, and lymph node enlargement in the right cervical region V were identified intraoperatively. Pathology (AP) revealed a malignant neoplasm of spindle cells, free margins, and absence of lymph node neoplasm. Immunohistochemistry (IHC) with a positive S100 marker corroborated the diagnosis of desmoplastic melanoma (MD). She was asymptomatic in follow-up, when 8months after surgery, she developed right axillary lymph node enlargement, measuring 4cm, painful, rigid and adherent, and loss to follow-up.

Discussão

MD is a rare form of melanoma, accounting for 1-4% of melanoma cases. It manifests as an amelanotic papule or nodule, with a fibrous consistency, in an area of ​​sun exposure, especially in the head and neck. Due to the clinical nonspecificity, the tumor simulates more prevalent malignant and benign pathologies, delaying the correct diagnosis. As in the present case, the cancer is usually infiltrative, invading the dermis and subcutaneous tissue. AP shows fusiform melanocyte infiltrate and may exhibit patterns of desmoplasia, neurotropism, and neural differentiation. According to the degree of desmoplasia, MD is divided into pure and mixed. The mixed form is characterized by <90% desmoplastic involvement and has a worse prognosis. Thus, the IHC is of great importance for diagnostic confirmation. Lymphatic involvement is less frequent than in common melanomas. Therefore, sentinel lymph node biopsy should be discussed, assessing the risk of lymph node disease, comorbidities, and life expectancy. The treatment of choice is complete surgical excision, safety margins should be proposed according to tumor thickness and histological subtype.

Comentários Finais

The unusual MD differs from melanoma in clinical and tumor pathobiology. Due to its atypical characteristics, it presents itself as a diagnostic, and therapeutic challenge for the oncologic surgeon, who must be able to recognize and conduct the appropriate treatment, in order to obtain better survival results.

Palavras Chave

Melanoma; Surgical Oncology; Radiotherapy, Adjuvant