[Clinicopathological study on the follicular dendritic cell sarcoma].

OBJECTIVE

To investigate the clinicopathologic features and differential diagnostic methods for follicular dendritic cell sarcoma.

METHODS

Histological and immunohistochemical examinations and EBER in situ hybridization were used to investigate the pathological features of 5 cases of follicular dendritic cell sarcoma, and related literature was reviewed.

RESULTS

There were 3 males and 2 females with a median age of 54 years (range, 28 - 75 years). The location of lesions included lymph node (2 cases), tonsil (1 case), stomach (1 case), and liver (1 case). The growth patterns were fascicular or whorls and/or diffuse. The neoplastic cells were spindle or ovoid in shape with indistinct border and slightly eosinophilic cytoplasm. The nuclei were round, oval or spindle in shape with small distinct nucleoli. Warthin-Finkeldey-like multinucleated giant cells were detected in two cases. Mitotic figures were found in 1-22/10 HPF. Immunohistochemical staining showed that CD21 and CD23 (3 of 5), CD35 (4 of 5), D2-40 (4 of 4), and CXCL13 (3 of 4) were positive in neoplastic cells. EBER was detected in one of five cases by in situ hybridization. Four cases were followed-up for 6 approximately 25 months and no recurrence or death was observed yet.

CONCLUSION

Follicular dendritic cell sarcoma is an extremely rare and should be considered as a moderately malignant tumor, and may present histological polymorphism with certain distinctive features. Immunohistochemistry is necessary in differential diagnosis to distinguish from other tumors.