A case of hyalinizing spindle cell tumor with giant rosettes in the presacral region. Immunohistochemical and ultrastructural study
De Pinieux, G.; Anract, P.; le Charpentier, M.; Carlioz, A.; Coindre, J.M.; Vielh, P.; Tomeno, B.; Forest, M.
Annales de Pathologie 18(6): 488-491
1998
ISSN/ISBN: 0242-6498 PMID: 10051917 Document Number: 484866
Hyalinizing spindle cell tumor with giant rosettes is a slowly growing tumor with a risk of local recurrence in case of incomplete surgical excision that could be regarded as a distinctive type of low-grade fibroblastic tumor. We report a case involving the presacral area. This tumor was composed of areas of bland spindle cell proliferation with a fascicular pattern in a fibrous or myxoid stroma, intermixed with giant rosettes consisting of rounded cells surrounding a central collagen core. The tumor expressed vimentin, and, for cells comprising the rosettes, S-100 protein, NSE and CD-57. These latter cells exhibited ultrastructural features of Schwann cells, the tumoral cells of fascicular area exhibiting features of fibroblastic cells. Flow cytometry showed DNA-aneuploidy and a very low S-phase fraction. This tumor appeared to be composed of two cellular components, fibroblastic and Schwann cells, located, at the opposite of neurofibroma, in two distinct areas.