Trabecular carcinoma of the skin: further clinicopathologic and morphologic study.

We studied the clinical aspects of 30 cases of trabecular carcinoma of the skin. Twenty-three patients were followed up for more than one year. Trabecular carcinoma of the skin is often misdiagnosed as a metastatic malignant tumor. The average age at the time of diagnosis was 68 years; most tumors occurred during the seventh and eighth decades of life. Most initial lesions were located in the head, neck, and upper extremities. Lymph node metastases developed in 13 patients, three of whom eventually died of the disease. Local recurrence developed in ten patients, four of whom died of metastatic trabecular carcinoma. The overall mortality was five of the 30 patients. Three of the patients in whom generalized metastases developed also suffered from some other severe systemic disorder. Nearly half of the 23 patients are free of disease. Sweat gland differentiation was observed in two cases, which indicates that the cell of origin is a multipotential unit capable of both neuroendocrine and sudoriferous differentiation.