Skeletal-Muscle Tumors

摘要

Rhabdomyosarcoma (RMS) is a malignant tumor with differentiation towards skeletal muscle and is the most common sarcoma of childhood. Four main subtypes are recognized in the current WHO classification: embryonal, alveolar, spindle cell/sclerosing, and pleomorphic. The embryonal subtype of RMS accounts for approximately 60% of cases and the alveolar subtype accounts for 20%. Pediatric RMS belongs to the group of small round blue-cell tumors, neoplasms that are commonly examined by fine-needle aspiration (FNA) cytology [1-10]. The sensitivity and specificity for this group of tumors exceed 90% and with an adequate sampling and the use of ancillary techniques a diagnosis of a specific histologic subtype can be rendered in the majority of cases [4, 11-13]. Benign and malignant striated muscle tumors are uncommon in adults in general, but the rare pleomorphic RMS occurs exclusively in adults.