[114] Chondroid Tenosynovial Giant Cell Tumor of the Temporomandibular Joint: Clinicopathologic and Immunohistochemical Analysis of 5 New Cases

GJ Smalberger, R Garcia, BL Hoch. University of Washington, Seattle, WA; Mount Sinai Medical Center, New York, NY

Background: Chondroid metaplasia in tenosynovial giant cell tumor (TGCT) is rare with only 4 well documented cases reported in the literature, 2 of which involved the temporomandibular joint (TMJ). We report 5 new cases of chondroid TGCT all arising in the TMJ. The clinicopathological and immunohistochemical features and distinction from other chondroid lesions involving the TMJ are discussed.
Design: Five cases of TGCT with areas of chondroid metaplasia involving the TMJ were retrieved from our files. Routine H&E sections were reviewed for the extent of chondroid metaplasia, patterns of matrix formation and mineralization, cellular composition of conventional TGCT within the tumor, architecture, and bone invasion. Immunohistochemical stains for Clusterin, D2-40, Desmin, CD163 and S100 protein were performed using an ABC method. Follow-up information was obtained from the medical record.
Results: Three patients were male and two female. Age ranged from 36-70 (mean=49) yrs. Average tumor size was 3.9 (3.1-4.5) cm. Grossly, tumors had a red-brown or grey-white appearance depending on the extent of chondroid metaplasia present. All cases were nodular and grew with a pushing front without bone invasion. Chondroid metaplasia had a geographic or lobular architecture, was extensive in three cases comprising over 90% of the tumor, and was less extensive (30%) in the other two. The matrix ranged from poorly formed and myxoid with lace-like calcification to better developed hyaline-like cartilage with more diffuse calcification. The conventional TGCT component contained multinucleated giant cells, large mononuclear synovial cells, and smaller histiocytic cells containing hemosiderin. Staining for Clusterin and D2-40 was seen in the large cells in both the chondroid and conventional components in all 5 cases. Large cells were focally positive for Desmin in 2 of 5 cases. CD163 highlighted a population of smaller histiocytes in 4 of 5 cases. Variable staining for S100 in chondroid areas was seen in 3 of 5 cases. Follow-up ranging from 8 to 67 (ave=29) months was available in all cases . One patient had recurrent disease 3 years after an initial excision.
Conclusions: Chondroid TGCT is a rare, distinct synovial tumor with a predilection for the TMJ that needs to be distinguished from other chondroid lesions, including chondroblastoma and chondrosarcoma, in this region. Chondroid metaplasia may be extensive. Recurrences do occur, but seem to be uncommon.
Category: Bone & Soft Tissue

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 21, Tuesday Morning

 

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