-Associated Neoplasms: A Rapidly Expanding Family of Lesions.

Nearly 20 years ago, the first description of a translocation involving chromosome 17 on which resides was described. Since then, not only the culprit gene but also many fusion partners, leading to transcriptional activation of , have been detected. The first neoplasm known to harbor rearrangements was aneurysmal bone cyst. Since then, other entities like nodular fasciitis, myositis ossificans, fibro-osseous pseudotumor of digits, and a subgroup of fibromas of tendon sheath, probably representing tenosynovial nodular fasciitis, have been added to the list of -rearranged lesions. Remarkably, all of them share clinical as well as morphological characteristics, and authors have suggested that these entities actually belong to the same spectrum. This review summarizes the current knowledge regarding -rearranged lesions and further elaborates on how these neoplasms relate to one another. We propose to call these lesions UAN (-associated neoplasm).