Chondroid Tenosynovial Giant Cell Tumor of the Temporomandibular Joint: A Rare Case Report

Abstract Tenosynovial giant cell tumor of diffuse type (TGCT-d) or pigmented villonodular synovitis (PVNS) is a locally aggressive lesion that mostly affects the joints of long bones. Chondroid tenosynovial giant cell tumor (CTGCT) or PVNS with chondroid metaplasia is a rare distinct subset of synovial tumors that has a predilection for the TMJ. We report a rare case of CTGCT in the TMJ, initially misdiagnosed as temporomandibular disorder (TMD). A 51-year-old woman was referred to the surgeon with the chief complaint of TMJ pain for 5 years and a past history of an unsuccessful TMD treatment. Extraoral examination revealed discrete preauricular swelling and restricted mandibular range of motion. Panoramic radiograph and computerized tomography showed destruction of the mandibular fossa and condyle. Histologically, the tumor was composed by large mononuclear cells with prominent eosinophilic cytoplasm and grooved nuclei, small histiocytoid cells, osteoclast-like multinucleated cells, brown pigmentation and areas of chondroid metaplasia. Morphological and immunohistochemical characteristics lead to the final diagnosis of CTGCT. The rarity of CTGCT could be attributed to the lack of recognition of this lesion, with cases diagnosed as chondroblastomas, synovial chodromatosis and chondrosarcoma. The patient received immediate reconstruction and recurrence was found 22 months after initial intervention. TGCT-d and CTGCT of the TMJ can present similar symptoms to TMD, but clinicians must distinguish both lesions by complete examination, imaging and, when necessary, histopathologic evaluation.

摘要：弥漫性腱鞘巨细胞瘤（Tenosynovial giant cell tumor of diffuse type, TGCT-d）又称色素沉着绒毛结节性滑膜炎（pigmented villonodular synovitis, PVNS），是一类主要累及长骨关节的局部侵袭性病变。软骨样腱鞘巨细胞瘤（Chondroid tenosynovial giant cell tumor, CTGCT）即伴软骨化生的色素沉着绒毛结节性滑膜炎，是一类罕见的独特滑膜肿瘤亚型，好发于颞下颌关节（temporomandibular joint, TMJ）。本文报告1例罕见的颞下颌关节（TMJ）软骨样腱鞘巨细胞瘤（CTGCT）病例，该病例最初被误诊为颞下颌关节紊乱病（temporomandibular disorder, TMD）。患者为51岁女性，因颞下颌关节疼痛5年就诊，既往曾接受TMD治疗但疗效不佳。口外检查可见耳前局限性肿胀，下颌活动受限。曲面体层片及计算机断层扫描显示下颌窝及髁突骨质破坏。组织学检查可见肿瘤由胞质嗜酸性显著、伴核沟的大单核细胞、组织细胞样小细胞、破骨细胞样多核巨细胞、棕褐色色素沉着区域及软骨化生区域构成。结合形态学及免疫组织化学特征，最终确诊为CTGCT。该病变的罕见性可归因于临床对其认识不足，既往病例曾被误诊为成软骨细胞瘤、滑膜软骨瘤病及软骨肉瘤。患者接受了即刻重建术，术后22个月复查发现复发。TMJ部位的TGCT-d与CTGCT临床表现与TMD相似，临床医师需通过全面检查、影像学检查，必要时结合组织病理学评估对二者进行鉴别。