Alveolar Rhabdomyosarcoma : Microscopic
Alveolar Rhabdomyosarcoma (ARMS) - Microscopic Features: The tumor cells in ARMS have round, oval, or crescentic hyperchromatic nuclei and scant cytoplasm. Nuclei may have grooves or irregular folds. Apoptotic cells and mitotic figures are common. Differentiating rhabdomyoblasts with abundant eosinophilic cytoplasm are seen in about 30% of cases. Multinucleated giant cells are a helpful diagnostic feature of alveolar RMS. They have a wreath-like appearance with multiple nuclei placed around the periphery of the cell containing abundant pale-pink cytoplasm.