Malignant diffuse-type tenosynovial giant cell tumors: a series of 7 cases comparing with 24 benign lesions with review of the literature.

BACKGROUND: Malignant diffuse-type tenosynovial giant cell tumor (D-TSGCT), an unusual sarcoma with concurrent or previous benign D-TSGCTs, poses challenges to diagnosis and prognostication. METHODS: We described the radiologic, clinicopathologic, and immunophenotypical findings of 5 primary and 2 metachronous malignant D-TSGCTs and reviewed published cases to better delineate their morphologic spectrum and behavior. Twenty-four benign D-TSGCTs were also statically compared to analyze the diagnostic values of various variables. RESULTS: The 7 malignant cases affected 4 females and 3 males aged 45 to 78 (mean, 60.9) years, which included 1 intraarticular and 6 extra-articular lesions. These tumors were 5 to 17 cm (mean, 9.4) and located within or near the large joints of extremities. Magnetic resonance imaging revealed expansile or infiltrative masses with frequent lobulation and heterogeneous signals. Histologically, areas of benign D-TSGCTs blended abruptly or gradually with frank sarcomas composed of pleomorphic, spindle, or enlarged oval cells, forming malignant fibrous histiocytomalike (n = 4), fibrosarcomatous (n = 1), myxosarcomatous (n = 1), or giant cell tumorlike (n = 1) patterns. One patient experienced recurrences twice, and another 3 developed metastases to the lymph nodes (n = 2), lung (n = 1), or vertebrae (n = 1), with 1 dying from disseminated diseases. An older age (P = 0.003), a larger size (P = 0.036), tumor necrosis (P < 0.001), atypical mitoses (P < 0.001), and Ki-67 overexpression (P < 0.001) appeared preferentially in malignant lesions, but these parameters had overlap between few benign and malignant tumors. CONCLUSIONS: Malignant D-TSGCTs are a distinct sarcoma with considerable morphologic variability, metastatic propensity, and lethality. Altered architecture with anaplastic cells represents an important distinguishing feature, while abnormalities of other parameters should not be directly equated with malignancy.

Anaplastic large cell lymphoma--a rare disorder in southern Taiwan.

Anaplastic large cell lymphoma (ALCL) is a subgroup of non-Hodgkin's lymphomas with large lymphoma cells expressing CD30 antigen. This entity has rarely been reported in Taiwan. We performed a retrospective clinicopathologic study in a medical center in southern Taiwan during a 13-year period and identified 13 cases. There were 10 males and 3 females with a median age of 49 years old. Seven presented with pure nodal disease and 5 had bony involvement. The staging results were stage I (5 patients), II (1), III (1), and IV (4). The pathologic subtypes were common variant (10), lymphohistiocytic variant (2), and small cell variant (1). Eleven tumors were of T-cell lineage; 2, null-cell. Immunohistochemically, 5 tumors (38.5%) expressed cytotoxic markers, T-cell intracellular antigen-1 and/or granzyme B. Two tumors (15.4%) expressed anaplastic lymphoma kinase (ALK). Long-term follow-up information was available in 8 patients. The 2 patients with ALK-expressing tumors (37 and 49 years old) were free of disease for 61 and 54 months, respectively. The other 6 patients were either died of disease (5 patients) or experienced relapse with progressive disease (1). In conclusion, we reported the largest series of ALCL in Taiwan. We confirmed ALK-expressing ALCL carries favorable prognosis and ALK-negative ALCL has similar poor prognosis as non-anaplastic T-cell lymphoma. As compared to the previous reports from the West, our ALK positive rate was lower and the age of our ALK-positive patients was older. A larger national or multi-institutional study is needed for further characterization of ALCL in Taiwan.