Abstract
A 53-year-old woman complained of a 2-year history of a mass in the left thumb. After an ultrasound imaging test at another hospital, she came to our hospital for evaluation of a possible solid tumor. At her first visit, physical examination revealed a subcutaneous immovable mass with a smooth surface and yellowish brown color, measuring 16×16mm on the dorsal aspect of the interphalangeal (IP) joint of the left thumb. Magnetic resonance imaging revealed that the lesion on the dorsal aspect of the IP joint of the left thumb was hypointensive on a T1-weighted image, hypointense and hyperintense on a T2-weighted image, the bone cortex of the lesion was not clear on T1- and T2-weighted images, and it was enhanced by contrast medium. A skin biopsy was performed and histopathological examination revealed the infiltration of histiocyte-like cells, epithelioid cells, foamy cells, and osteoclast-like multinucleated giant cells in the deep area of the dermis and subcutaneous tissue. Most of the infiltrating cells were positively stained by CD68. On the basis of these findings, a diagnosis of giant cell tumor of tendon sheath was made. To date, there have been 26 cases including our patient reported in the Japanese literature in the field of dermatology since 2000, and the most common site of GCTTS is the finger, in which 15 cases have been reported. Skin Research, 11: 308-312, 2012
