Primary intracerebral angiomatoid fibrous histiocytoma: report of a case with a t(12;22)(q13;q12) causing type 1 fusion of the EWS and ATF-1 genes.

Angiomatoid fibrous histiocytoma (AFH) is generally considered a soft tissue sarcoma of low malignant potential that occurs in children/young adults and most frequently affects the extremities. AFH infrequently recurs and rarely metastasizes. AFH has a characteristic histomorphology, and immunohistochemical reactivities for desmin and CD68 have led to myofibroblastic and fibrohistiocytic histogenetic hypotheses, respectively. Although only a limited number of AFH cases have been molecularly characterized, many have demonstrated evidence of an underlying translocation event. Reverse transcription-polymerase chain reaction and fluorescence in situ hybridization studies suggest that chromosomal rearrangement in AFH most frequently involve the EWS, CREB, ATF-1, and FUS genes. We report the first pathologically confirmed case of an AFH presenting as an intracerebral primary in a previously healthy 25-year-old man. Genetic analyses revealed a t(12;22)(q13;q12) and a unique underlying clear cell sarcomalike type 1 EWS/ATF-1 gene fusion.