Cytologic findings of alveolar soft part sarcoma presenting with multiple pulmonary masses - A case report with review of literature -

Alveolar soft part sarcoma (ASPS) is a rare malignant soft tissue tumor of uncertain origin, and it has a strong propensity for metastasis to the lungs, bones and brain. We report upon an unusual case of ASPS, presenting as multiple lung nodules with no other detectable primary site, in a 44-year-old man. A fine needle aspiration of the nodules yielded scattered, discohesive cells, each containing an eccentrically displaced nucleus and prominent nucleolus, on a granular background. Tumor cells with numerous bared nuclei, and occasional sheets of epithelioid cells were also found. Under the cytological diagnosis of an unclassified epithelioid malignant tumor, resection of the lung nodules was performed. The histologic findings were consistent with ASPS, showing positive TFE3-nuclear immunoreactivity. There is limited literature concerning cytological findings associated with pulmonary ASPS: especially in cases where the primary site is unknown. Here, we present a cytological review of pulmonary ASPS, investigating the significance of TFE3 staining in the diagnosis of ASPS.