Primary pulmonary rhabdomyosarcoma: a case report and review of the literature.

Although several primary pulmonary neoplasms containing striated muscle fibers have in the past been described as rhabdomyoma or rhabdomyosarcoma, it was not until 1939 that McDonald and Heather described the first acceptable case of this neoplasm. Since then 13 such cases have been reported in the world literature. Previously reported cases of the neoplasm are reviewed and the salient features described. The origin of the striated muscle fibers has been much debated. Some believe that they develop from myoblastic differentiation of primitive mesenchymal cells or metaplastic transformation of pleuripotential mesenchymal cells present in the bronchial walls and pulmonary interstitium, whereas others claim that they develop from misplaced striated muscle tissue from the pharyngeal or esophageal region. A case report of the pleomorphic type of primary pulmonary rhabdomyosarcoma with multiple hematogenous metastases is presented as well as a review of the literature with a discussion of the histogenesis.