title: Solitary fibrous tumor of the oral cavity with a predominant leiomyomatous-like pattern: A potential diagnostic pitfall.
abstract: The diagnosis of solitary fibrous tumor (SFT) is usually straightforward if the typical morphologic features, including a wide variety of growth patterns, are identified. We report the clinical, radiologic, and pathologic findings of a rare case of intraoral SFT which exhibited a predominant leiomyomatous-like appearance, closely reminiscent of a leiomyoma, at both incisional and excisional biopsy. Histologically, the tumor was composed predominantly of intersecting fascicles of eosinophilic spindle-shaped cells, variably set in a fibrous stroma. A focal hemangiopericytoma-like growth pattern with alternating hypercellular and hypocellular areas, as well as the deposition of dense keloid-type collagen, raising the suspicion of SFT, could be identified only after a careful examination of the whole tumor. Immunohistochemistry was helpful in confirming the diagnosis of SFT, revealing a diffuse staining of neoplastic cells for vimentin, CD34, bcl-2 protein, and, focally, CD99. Myogenic markers (alpha-smooth muscle actin, desmin, h-caldesmon) were not expressed. The pathologist should be aware of this variant of intraoral leiomyomatous-like SFT to avoid a misdiagnosis of leiomyoma. The distinction of SFT from leiomyoma in the oral cavity is important to assure both correct treatment and prognostic information.
authors.affiliation: Dipartimento G.F. Ingrassia, Anatomia Patologica, Policlinico Universitario G. Rodolico, Università di Catania, Via S. Sofia 87, Catania 95123, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Amico
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Colella
authors.forename: Raffaele
authors.initials: R
authors.lastname: Rossiello
authors.forename: Giada
authors.initials: G
authors.lastname: Maria Vecchio
authors.forename: Pietro
authors.initials: P
authors.lastname: Leocata
authors.forename: Gaetano
authors.initials: G
authors.lastname: Magro
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007889:Leiomyoma / Q000473:pathology; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology*; D054364:Solitary Fibrous Tumors / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor