Biphasic intraabdominal desmoplastic small round cell tumor: Fine‐needle aspiration cytology findings

The present report describes the case of a 9-yr-old boy with an abdominal desmoplastic small round cell tumor (DSRCT) which on fine-needle aspiration cytology and histology revealed a biphasic pattern, making initial diagnosis difficult. Epithelial-like clusters of cells and loosely-arranged poorly-differentiated cells with scant cytoplasm associated with cells having a larger nucleus and multinucleated larger cells represented the smears' counter-part of epithelial clusters and lobules and sarcomatous-like tissue recognized in the histologic sections. Multinucleated cells were common in the sarcomatous-like areas of the tumor. The biphasic pattern was highlighted by immunohistochemistry. Keratin and epithelial membrane antigen stained predominantly or only the epithelial component, while desmin diffusely decorated the sarcomatous areas and the epithelial cells as a paranuclear cytoplasmic dot. Immunosera 013 mainly stained the sarcomatous component.