title: An unusual mucinous osteoma with features of an ossifying fibroma in the nasal cavity of a horse.
abstract: A 4-month-old Warm-blooded colt presented with facial distorsion and an abnormal respiratory noise of 2 weeks' duration. A proliferative mass was found endoscopically and by computer tomography. Clinical differential diagnosis included cyst formation of the concha, malformation and neoplasia. Euthanasia was followed by post-mortem examination, which revealed a well-circumscribed, semi-solid, jelly like structure, measuring 14.5 x 9.0 x 12.0 cm, in the left posterior nasal cavity extending into the left frontal and maxillary sinus. Histologically, the mass consisted of trabeculae of woven bone, focal lamellar bone and fibroblast proliferation within a moderate fibro-vascular stroma. Abundant mucin production was noted within areas of fibroblastic differentiation. Some areas contained irregularly shaped spicules of osteoid rimmed by osteoblasts, randomly distributed within a moderately vascularized, fibro-osseous stroma. On the basis of the histopathological features, a nasal mucinous osteoma with focal ossifying fibroma-like structures was diagnosed.
authors.affiliation: Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Puff
authors.forename: B
authors.initials: B
authors.lastname: Ohnesorge
authors.forename: R
authors.initials: R
authors.lastname: Wagels
authors.forename: W
authors.initials: W
authors.lastname: Baumgärtner
mesh_terms: D000818:Animals; D003937:Diagnosis, Differential; D004724:Endoscopy / Q000662:veterinary; D018214:Fibroma, Ossifying / Q000000981:diagnostic imaging / Q000473:pathology* / Q000662:veterinary; D006736:Horses; D009077:Mucins / Q000096:biosynthesis; D009296:Nasal Cavity / Q000000981:diagnostic imaging / Q000473:pathology*; D009669:Nose Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000662:veterinary; D010016:Osteoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000662:veterinary; D014057:Tomography, X-Ray Computed / Q000662:veterinary
chemical_list: D009077:Mucins