Alveolar Soft Part Sarcoma of Nasal Cavity showing Unusual Histologic Feature: A Case Report

Alveolar soft part sarcoma (ASPS) is a rare mesenchymal neoplasm. It affects young adults more and occurs more frequently in the extremities. ASPS is exceedingly rare in the nasal cavity. We report a case of ASPS in the nasal cavity of a 17-year-old female. Its most striking features included organoid and pseudoalveolar arrangement of tumor cells, which were large and polygonal, with vesicular nuclei and abundant eosinophilic cytoplasm rich in granules. There were PAS-positive, diastase-resistant crystalline rods within the cytoplasm. Our case displayed inapparent pseudoalveolar growth pattern and frank pleomorphism. The diagnosis of ASPS, which presents uncommon morphologic findings in unusual sites, is challenging. Recognition of ASPS is greatly assisted by attention to its characteristic cytological features, including intracytoplasmic crystals and immunohistochemistry showing absence of skeletal muscle, epithelial, and neuroendocrine markers.