Uncommon Manifestations of Common Malignancies

Abstract

metastases from malignant pleural mesothelioma to the chest wall due to direct extension, as well as distant sites after extrapleural pneumonectomy, have been described. 1-3 However, soft-tissue distant locations are very infrequent. A Tru-Cut biopsy was performed, which revealed an infiltration of gluteal muscle by a malignant proliferation of epithelioid cells having a pseudoglandular pattern of growth interspersed within muscle fibers. Immunophenotype of the neoplasm (calretinin, epithelial membrane antigen, and cytokeratin AE1/AE3positive and carcinoembryonic antigen-negative) was decisive, 4 and the diagnosis of metastasis from epithelioid malignant mesothelioma was made (Figs 2A and B). The patient then received six cycles of chemotherapy with an antracycline regimen, achieving partial remission of the buttock lesion and stabilization of thoracic disease. Unfortunately, eventual progression of thoracic disease and retroperitoneal lymph node metastases with ascitis occurred.