Solid variant of alveolar rhabdomyosarcoma mimicking non-Hodgkin lymphoma: case report and review of literature.

Alveolar rhabdomyosarcoma is a high-grade neoplasm, which forms about 30% of rhabdomyosarcomas. A rare solid variant has been described. A 14-year-old girl presented with inguinal lymph nodal mass and was treated with 6 cycles of CHOP chemotherapy and local radiation. After 3 months, she presented with generalized lymphadenopathy, pleural and pericardial effusions. A histopathologic diagnosis of solid variant of alveolar rhabdomyosarcoma was made. The skeletal muscle origin was confirmed by positive immunostaining for desmin. A primary site was identified in the lower limb muscles. The patient was treated with salvage chemotherapy but had progressive disease. The pediatric and adolescent cases of this rare tumor reported in English language literature are reviewed. In addition, the importance of biopsy in the diagnosis of suspected lymphomas and the pitfalls of needle aspirations are briefly discussed.