A. Brief Descriptions：
The most common soft tissue sarcoma of children.
Predominantly in infants and children, and rare in patient older than 40 years.
Predominant in the head and neck, genitourinary tract and retroperitoneum, and the extremities.
B. Gross Findings：
Multi-nodular, or polypoid with a glistening, gelatinous, gray-white surface.
C. Micro Findings：
Consist of sheets of both malignant round and spindle cells in a variably myxoid stroma.
The rhabdomyoblasts are large and round and have abundant eosinophilic cytoplasm.
Four histological categories:
Botryoid rhabdomyosarcoma (variant of embryonal type).
Robbins Pathologic Basis of Disease, 6th ed. P1265-1266.
【 Fig. 153-1 (LP)】Composed of malignant small round cells.
【 Fig. 153-2 (LP)】The rhabdomyoblasts are large and round and have abundant eosinophilic cytoplasm.
【 Fig. 153-3 (LP)】