Subsequently occurring leiomyosarcoma and desmoid tumor of the right thigh.

Summary We present the case of a 44-year-old patient with a primary leiomyosarcoma of the right upper thigh, who developed a second mesenchymal lesion at the same thigh, diagnosed as an extra-abdominal desmoid tumor, some months after surgical treatment of his leiomyosarcoma. Clinically, histomorphologically, DNA cytometrically, immunohisto- chemically and radiologically the different histogenetic origin of the two lesions could be proven. The patient died 17 months after his first tumor diagnosis of lung metastases of his leiomyosarcoma.