Fine Needle Aspiration Cytology of Chondroid Tenosynovial Giant Cell Tumor of the Hand

Fine-needle aspiration cytology of diffuse type tenosynovial giant cell tumor with malignant trasformation and review of literature

Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath. Diffuse type often affects large joints, has higher recurrence rates, metastases, and malignant transformation potential compared to the localized type. The cytopathology of TGCT, a fibrohistiocytic neoplasm distinct from other giant cell-rich soft tissue tumors, is rarely reported. Here we describe cytomorphology of a case of TGCT that was initially diagnosed on fine-needle aspiration cytology (FNAC) consisting of a mixture of singly scattered polygonal or spindle mononuclear cells with hemosiderin laden macrophages, inflammatory cells, and a population of multinucleated osteoclast-like giant cells. Persistent symptoms and repeat excision were consistent with high-grade malignant transformation of the TGCT. Atypical cytologic features in a recurrent, infiltrative, or a metastatic lesion should raise suspicion for malignancy.

Tenosynovial Giant Cell Tumor, Localized Type With Extensive Chondroid Metaplasia: A Case Report With Immunohistochemical and Molecular Genetic Analysis

Tenosynovial giant cell tumor (TSGCT) of localized type is a common disease occurring mostly in the hands. Diagnosis of this tumor is relatively easy to render with hematoxylin-eosin-stained sections as compared with that of TSGCT of diffuse type. However, very rare cases with chondroid metaplasia that have recently been reported mainly in diffuse type can make pathological differentiation from soft tissue cartilaginous tumors extremely difficult. In this article, the authors present the second reported case of TSGCT of localized type showing extensive chondroid metaplasia. Pathological interpretation was difficult without utilizing immunohistochemistry and fluorescence in situ hybridization. One must be careful not to misdiagnose this lesion as cartilaginous tumors of soft tissue, and we suspect at least some chondroblastoma-like chondroma could be reclassified as TSGCT of localized type with extensive chondroid metaplasia. Morphological, immunohistochemical, and molecular genetic characteristics are presented and discussed.

Fine needle aspiration cytology diagnosis of metastatic malignant diffuse type tenosynovial giant cell tumor

Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath, and are classified into localized and diffuse types. Diffused type often affects the large joint, and has more recurrence, metastasis, and malignant transformation potential compared to the localized type. Malignant diffused TGCT (D-TGCT) usually occurs as a large tumor (>5 cm), in older patients, and its histopathologic features include necrosis, cellular anaplasia, prominent nucleoli, high nuclear cytoplasmic ratio, brisk mitosis, discohesion of tumor cells, paucity of giant cells, and a diffuse growth pattern. At least five of these criteria are required for the histopathologic diagnosis of malignant TGCT because the benign TGCT also shares many of these morphological features. We describe the cytomorphologic features of a malignant D-TGCT from an unusual case of pulmonary metastasis in an adult patient. Fine needle aspiration cytologic features of malignant D-TGCT have not been described earlier in the English literature.