Mediastinal leiomyosarcoma.

Leiomyosarcomas are extremely rare tumors which develop from smooth muscle, usually in rile esophagus and large vessels (inferior vena cava, pulmonary artery, and superior I,ena cava). In very rare cases, leiomyosarcomas deve lop from small vessels in the soft tissue of the mediastinum. Clinical expr ession of,mediastinal leiomyosarcomas (dysphagia, dysphonia) is related to their. large size and the subsequent compression of mediastinal structures. Ar pathology examination, the gross aspect is one of a spindle cell tumor: Microscopically, the tumor may be highly undifferentiated,making it necess ary to use specific immune markers (actin and desmin) or ultra-structured a nalysis to establish the diagnosis. Treatment of localized tumors is based on surgical excision, either alone or in combination with radiotherapy of t he mediastinum. Chemotherapy,, generally dexorubicin, is indicated in case of,metastatic dissemination, but outcome remains uncertain. As for all soft tissue sarcomas, the prognosis of mediastinal leiomyosarcoma depends on th e size of the tumor; its histological structure and irs resectability.