Adult rhabdomyosarcoma: Cross-sectional imaging findings including histopathologic correlation

OBJECTIVE. The purpose of our study was to present the MRI and CT features of adult rhabdomyosarcomas with histopathologic correlation. Forty- nine sequential cases were incorporated over a 5-year period from the sarcoma unit database. Twenty-six patients had adequate imaging (16 MRI, 10 CT) and histopathology available for retrospective review. The alveolar subtype was present in 13 patients, embryonal subtype in four patients, and pleomorphic subtype in nine patients. On both CT and T1-weighted MRI, all tumors were isodense to skeletal muscle, although enhancement was variable after the administration of IV contrast material. Pleomorphic tumors were very high signal on T2-weighted/STIR imaging, and both pleomorphic and alveolar subtypes were extremely heterogeneous. Embryonal tumors were more homogeneous. CONCLUSION. Although adult rhabdomyosarcomas have certain imaging appearances in common with other soft-tissue sarcomas, features at presentation such as tumor heterogeneity, site, regional lymphadenopathy, and pulmonary metastasis should make the radiologist consider this important diagnosis.