1994 Volume 33 Issue 6 Pages 1145-1149
Tenosynovial giant cell tumor, diffuse type, especially the extra-articullar form, is extremely rare.We report a case of this tumor in which a presumptive diagnosis was made by fine-needle aspiration cytology, after a malignant tumor was suspected clinically.
The patient was a 50-year-old female with a 13×8cm mass in the immediate vicinity of her right knee joint.We suspected a malignant tumor because of its size and radiographic findings, but fine-needle aspiration cytology suggested tenosynovial giant cell tumor (class II).Cytologic findings consisted of many histiocytotic cells, including cells with intracytoplasmatic hemosiderin-like granules, and xanthomatous cells.Multinucleated giant cells and spindle cells were also seen.The diagnosis by open biopsy was tenosynovial giant cell tumor, diffuse type.At operation, a solid mass was found centered on the pes anserinus, and did not involve the joint.Microscopically, the tumor displayed multilobulated, slit-like cavities and villus formation, so we made a diagnosis of tenosynovial giant cell tumor, diffuse type.Fine-needle aspiration cytology appeared to be useful in the diagnosis of tenosynovial giant cell tumor, diffuse type.
