Cytologic Findings of Alveolar Soft Part Sarcoma Presenting with Multiple Pulmonary Masses

Alveolar soft part sarcoma (ASPS) is a rare, epithelial-like, uniformly malignant tumor, with no benign counterpart, that principally affects young adults in their twenties and thirties. ASPS usually presents as a soft, painless, slow growing soft tissue mass, but it frequently metastasizes to the lungs, brain and bones. ASPS belongs to the high-grade, epithelioid/polygonal sarcoma category: exhibiting characteristic histological and ultrastructural features. However, immunohistochemical findings have been described as nonspecific. Based on morphological resemblance, expression of muscle actin, desmin, MyoD1, myogenin and alpha-striated actin-1, and cytoplasmic granules, a variant of paraganglioma, skeletal muscle origin tumor or a juxtaglomerular tumor, respectively, have been proposed. ASPSs are consistently negative for epithelial markers (cytokeratins and epithelial membrane antigen), neuroendocrine markers (chromogranin A and synaptophysin) and melanocytic markers (S100 protein, human melanoma black-45 [HMB-45] and melanA). Recently, specific translocation as fusion between transcription factor 3 (TFE3) gene, belonging to the microphthalmiaTFE subfamily of the basic helix-loop-helix leucine zipper, transcription factors and a novel gene alveolar soft part sarcoma locus (ASPL) in ASPS has been reported, and subsequently the TFE3 antibody has been used to diagnose ASPS. The characteristic histological findings help pathologists correctly diagnose ASPS, but a cytological diagnosis by fine needle aspiration (FNA) may be difficult as a primary modality because of the rare incidence of ASPS and the limited few cytology literature. In this case, cytological evaluation was even more problematic, because there was no primary tumor connected with presentation of the multiple lung nodules. In this report, we focused on the cytological features of pulmonary ASPS, along with its cytologic differential points and the diagnostic value of TFE3 immunostain. Cytologic Findings of Alveolar Soft Part Sarcoma Presenting with Multiple Pulmonary Masses