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Cytologic Features of Clear Cell Sarcoma (Malignant Melanoma) of Soft Parts
A Study of Fine-Needle Aspirates and Exfoliative Specimens

Andrew J. Creager MD, Martha B. Pitman MD, Kim R. Geisinger MD
DOI: http://dx.doi.org/10.1309/D17Q-2MWA-HVNX-H7RD 217-224 First published online: 1 February 2002

Abstract

We describe the cytologic features of clear cell sarcoma of soft tissue (CCS) in 11 fine-needle aspiration biopsy (FNAB) specimens and 6 exfoliative specimens from 11 patients. In 3 patients, FNAB was the initial method of tumor evaluation. In 6 of 11 cases, immunostaining with S-100 or HMB-45 was evaluated. Electron microscopic evaluation was performed in 1 case. Both the FNAB and exfoliative specimens varied in overall cellularity, although reproducible cytologic features were identified. A significant diagnostic pitfall, namely the potential of CCS to form microacinar structures mimicking adenocarcinoma, is described with particular reference to CCS metastatic to regional lymph nodes. A rare case of the granular cell variant of CCS is illustrated as well. Owing to the rarity of CCS, the diagnosis on cytologic smears is extremely difficult and is aided substantially by pertinent clinical data. The diagnosis can be made conclusively by FNAB in conjunction with immunocytochemical confirmation of HMB-45 or S-100 protein expression, cytogenetic demonstration of the t(12;22) translocation, or electron microscopic studies demonstrating melanosomes.

Key Words:
  • Cytology
  • Cytopathology
  • Fine-needle aspiration
  • Malignant melanoma of soft parts
  • Clear cell sarcoma
  • Pleural fluid
  • Ascites fluid
  • Cytogenetic
  • Immunohistochemistry
  • Electron microscopy