Giant Cell Tumor of Tendon Sheath in Supraclavicular Region: Cytological Aspect of a Common Tumor in an Uncommon Location

Abstract

Giant cell tumor of tendon sheath (GCTTS) is a common neoplasm, frequently developed around small digital joints of hand, and less commonly in wrist, ankle, foot and knee. GCTTS of other locations are very rare. The cytological feature of GCTTS is unique, but it could mimic neoplasm, inflammation or other lesions when arising in unusual locations. We reported a case of a 26-year-old male who presented with a supraclavicular mass. Microscopic features of excised mass revealed well-demarcated oval nodule, composed of polymorphous population of multinucleated giant cells and mononuclear cells with fibrous septa, consistent with the diagnosis of GCTTS. Local recurrence is not occurring during five-year follow-up. The purposes of this report is to present the rarity of this tumor in an exceedingly rare location and to help avoid misdiagnosis with other mimics. Keywords: giant cell tumor of tendon sheath, cytology, localized tenosynovial giant cell tumor DOI: 10.31524/bkkmedj.2019.02.017