Plexiform fibrohistiocytic tumor with a clonal cytogenetic anomaly

Plexiform fibrohistiocytic tumors are rare lesions of proposed myofibroblastic origin occurring primarily in infants and children. There is a characteristic biphasic histology comprised of both fibroblastic and histiocyte-like components. These tumors tend to be locally aggressive with prognosis dependent on completeness of resection. A previous cytogenetic case report of this tumor described a stemline clone with a karyotype of 46,XY,-6,-8, del(4)(q25q31),del(20)(q11.2),+der(8)t(8;?) (p22;?),+mar. We report a different cytogenetic finding in another plexiform fibrohistiocytic tumor which demonstrated a simpler karyotype of 46,XY,t(4;15)(q21;q15). The implications of cytogenetic heterogeneity in fibroblastic tumors is briefly discussed.