Primary rhabdomyosarcoma combined with chronic paragonimiasis in the cerebrum: a necropsy case and review of the literature.

A necropsy case of a primary rhabdomyosarcoma with chronic paragonimiasis in the cerebrum of a 68-year-old man is reported. The clinical data showed a right hemiplegia and dysarthria which became lethal in 6 months even though operation and radiation therapy were performed. Computed tomography revealed a large low-density area associated with the peripheral enhancement in the left basal ganglia, and multiple conglomerated calcified masses in the left temporal and occipital lobes. Biopsied and necropsied materials of the tumor in the basal ganglia was reddish brown in color and histologically was composed of purely mesenchymal derivatives with both embryonal and mature striated muscle cells but neither neuronal nor glial elements. Some of the tumor cells with extending slender cytoplasms showed obvious cross striations at the light and electron microscope levels and immunohistochemical reactivity for myoglobin. All tumor cells were also positive for vimentin, but not for glial fibrillary acidic protein. The clinical and necropsy findings revealed no primary lesion anywhere but in the brain. In addition, numerous dead oval eggs of Paragonimus westermani were found in many cystoid lesions encapsulated by thick connective tissues with calcification and/or ossification. Clinicopathological features of 24 cases of primary rhabdomyosarcoma of the central nervous system reported in the literature are reviewed briefly. The histogenesis of this tumor are discussed together with comments on cerebral paragonimiasis.