title: Malignant fat-forming solitary fibrous tumor (lipomatous hemangiopericytoma) in the neck: Imaging and histopathological findings of a case.
abstract: Fat-forming solitary fibrous tumor (SFT) is a rare variant of solitary fibrous tumor, a mesenchymal fibroblastic neoplasia with a particular branching hypervascular pattern. This tumor is usually classified as benign and only very few fat-forming SFTs with malignant histologic features have been reported. We report a histologically malignant fat-forming solitary fibrous tumor in a 61-year-old man, located in his neck. Ultrasonography examination was first performed showing a heterogeneous lesion, predominantly hyperechoic, with sound beam attenuation, containing two hypoechoic solid nodules. Magnetic resonance imaging and computed tomography examinations demonstrated a heterogeneous and predominantly adipose mass, containing post contrast enhancing solid nodules and thin septations. Treatment consisted of total removal of the lesion. Histologically, the tumor showed hypercellularity, numerous mitoses and cytological atypia, fulfilling the criteria for malignancy. The patient had no metastasis. This rare tumor may be confused with other fat-containing lesions on imaging examinations, mainly liposarcoma.
authors.affiliation: Department of Radiology, Barretos Cancer Hospital, Barretos, Brazil.
authors.forename: Alice Duarte
authors.initials: AD
authors.lastname: de Carvalho
authors.forename: Lucas Faria
authors.initials: LF
authors.lastname: Abrahão-Machado
authors.forename: Cristiano Ribeiro
authors.initials: CR
authors.lastname: Viana
authors.forename: Renato
authors.initials: R
authors.lastname: de Castro Capuzzo
authors.forename: Augusto Elias
authors.initials: AE
authors.lastname: Mamere
mesh_terms: D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D006393:Hemangiopericytoma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008067:Lipoma / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D054364:Solitary Fibrous Tumors / Q000000981:diagnostic imaging / Q000473:pathology*; D036542:Tomography, Spiral Computed; D014463:Ultrasonography
keywords: MRI; fat-forming; helical computed tomography; lipomatous hemangiopericytoma; magnetic resonance imaging; malignant solitary fibrous tumor; ultrasonography