Malignant thoracopulmonary small-cell ("Askin") tumor.

The clinical, radiographic, and pathologic features of 10 patients with documented malignant small-cell tumor of the thoracopulmonary region (Askin tumor) were reviewed. The tumor represents a distinct pathologic entity of neuroectodermal origin. Clinically, it presents as a chest-wall mass with or without pain. Its radiographic appearance is that of a soft-tissue mass with or without pleural or rib involvement, often with metastatic disease--to the skeletal system, bone marrow, thorax, and sympathetic chain. Two patients developed metastases to the adrenal gland and liver, one after autologous bone marrow transplantation. The radiologist should be aware of this entity and its pattern of metastatic spread since metastases are treated aggressively.