Translocation (1;4)(p31;q34) in nonossifying fibroma.

Nonossifying fibroma is a benign, lytic lesion of fibrous origin most often observed in the metaphyseal region of the long bones in children and adolescents. It is frequently asymptomatic and is often characterized by a history of spontaneous resolution. Herein, we report a clinicohistopathologically typical case of nonossifying fibroma arising in the tibia of an 18-year-old skeletally mature female. Conventional cytogenetic analysis revealed a reciprocal translocation involving bands 1p31 and 4q34 [t(1;4)(p31;q34)]. To the best of our knowledge, this is only the second reported case of a clonally aberrant nonossifying fibroma.