[Fibro-osseous pseudotumor of the digits: One of USP6-related fibroblastic/myofibroblastic tumors]

Abstract

Fibro-osseous pseudotumor of the digits is a benign tumour closely related to myositis ossificans. It is a rare lesion seldom reported in the literature. We report the case of a 33-year-old woman with lancinating pain in the first phalanx of the second finger of the right hand, associated with inflammation. The histopathological examination of the surgical excision biopsy of the lesion revealed a spindle-shaped proliferation within a sclerosing, hyaline, and osteoid stroma. In our observation, immunohistochemistry and molecular biology are the main elements that helped to establish the diagnosis and eliminate the various differential diagnoses, despite a non-specific histopathological aspect.

Keywords: Benign tumour; Biologie moléculaire; Fibro-osseous pseudotumour of the digits; Gène USP6; Immunohistochemistry; Immunohistochimie; Molecular biology; Pseudotumeur fibro-osseuse des doigts; Spindle-cell tumour; Tumeur bénigne; Tumeur à cellules fusiformes; USP6 gene.