Figure 4.

A 35-year-old woman with alveolar rhabdomyosarcoma of the ethmoid sinus metastatic to the breast. Direct smear of material from the ultrasound-guided, fine-needle aspiration of the breast mass stained by the Papanicolaou method shows a loose cluster (A) and single tumor cells (B) with fine nuclear chromatin, a high nuclear-cytoplasmic ratio, and scant cytoplasm. Immunohistochemical staining for myogenin (C) shows diffuse and strong nuclear positivity, supporting the diagnosis of rhabdomyosarcoma.