Elson B. Helwig

The clinical and pathologic features of cutaneous metastasis were studied in 724 patients, with histopathologic confirmation of both the primary tumors and the secondary lesions in the skin. Cutaneous metastatic lesions from carcinoma of the lung and kidney were usually found in men, were often recognized before the primary tumor, and appeared in almost every area of the skin surface. Metastasis from carcinoma of the breast to the skin occurred almost exclusively in women, tended to be localized to the anterior chest wall, and was usually found after the primary tumor. Most cutaneous lesions metastasizing from squamous cell carcinoma of the oral cavity were found on the face or neck of men in whom there was previous histologic documentation of the primary tumor.

In a study of 65 primary cutaneous leiomyosarcomas and 15 primary superficial subcutaneous leiomyosarcomas, tumors occurred at any age but were more common in middle age and most common on the extremities. They developed as solitary painful or tender intracutaneous or subcutaneous nodules. Microscopically, the cutaneous leiomyosarcomas consist of a poorly delineated proliferation of spindle-shaped atypical myomatous cells arranged in interlacing fascicles which merge into collagenous stroma. Subcutaneous leiomyosarcomas are more sharply circumscribed and typically include a vascular pattern. About 40% of the cutaneous leiomyosarcomas recurred, but none metastasized despite a high mitotic frequency and marked cytologic atypia. Among the 12 patients with subcutaneous leiomyosarcomas, one-half of the tumors recurred and one-third eventuated in metastasis or tumor-related death. Cutaneous leiomyosarcomas have a relatively benign biologic course and may be excised conservatively, but are less likely to recur if the local excision is wide enough to require a skin graft for closure of the surgical defect. For primary subcutaneous leiomyosarcoma, early wide local excision with adequate clear histologic borders constitutes rational treatment.

Fifty-three examples of developmental "tailgut cysts" in the retrorectal space occurred predominantly in women and caused symptoms of mass effect or pain in 51%. The lesions were usually multicystic and lined by a variety of epithelial types, including ciliated columnar, mucin-secreting columnar, transitional, and squamous epithelium. Inflammation was present in 50%. In one patient a poorly differentiated adenocarcinoma was present. These cysts are most likely derived from remnants of the embryonic tailgut and differ from teratomas. Complete excision of the multilocular and multicystic process prevents recurrent draining sinuses and eliminates the possibility of malignant change.