ALVEOLAR SOFT PART SARCOMA - REPORT OF A CASE DIAGNOSED BY NEEDLE ASPIRATION CYTOLOGY AND ELECTRON-MICROSCOPY

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare tumor, account ing for less than 1% of all primary soft tissue malignant neoplasms. T he tumor is a distinct clinicopathologic entity, but its histogenesis is controversial. CASE: The needle aspirate from a soft tissue tumor i n a 15-year-old girl was stained with Diff-Quik and periodic acid-Schi ff (PAS) with and without prior digestion with diastase. Minute tumor tissue fragments were processed for transmission electron microscopic examination (EM). Clustered malignant cells with ill-defined, frothy o r vacuolated cytoplasm showed a positive reaction with PAS and PAS wit h prior diastase digestion and oval nuclei containing macronucleoli. I ntracytoplasmic, membrane-bound, rhomboid and rod-shaped crystals with a regular lattice pattern with 50-80 Angstrom periodicity were detect ed by EM study of aspirated tumor cells. CONCLUSION: Light and EM stud ies of aspirated tumor cells showed diagnostic features of the tumor.