Cytogenetic abnormalities in follicular dendritic cell sarcoma: report of two cases and literature review

The identification of chromosomal abnormalities in many hematopoietic and mesenchymal neoplasms has contributed significantly to classification systems. Follicular dendritic cell (FDC) sarcoma is an intermediate-grade malignancy with morphological and immunophenotypic features of follicular dendritic cells. Available data on genetic changes in this neoplasm are limited, with only isolated case reports of cytogenetic abnormalities. We reviewed histological, immunophenotypic and cytogenetic findings in two cases of FDC sarcoma. The two cases of FDC sarcoma, were observed in female patients, one was nodal and one extranodal and they exhibited relatively complex karyotypes, characterized by structural abnormalities and loss of multiple chromosomes. One patient had several disease recurrences. At the last follow-up both patients were alive with no residual disease. The cytogenetic findings in these two cases, coupled with the few previously described abnormal karyotypes, suggest that FDC sarcoma is cytogenetically diverse.