Intranasal proliferative fibro-osseous dysplasia in a domestic longhair cat

Abstract

Case summary A 13-year-old female domestic longhair cat was presented for further investigation of chronic sneezing combined with a right-sided nasal discharge. A CT scan of the head revealed a locally invasive, aggressive right nasal mass radiographically consistent with a malignant neoplastic process. Histopathology on rhinoscopically guided biopsies revealed an unusual pathology consistent with fibro-osseous hyperplasia/dysplasia. Surgical treatment via a ventral rhinotomy and curettage was performed, and the diagnosis confirmed by repeat histopathology. The cat’s clinical signs significantly improved postoperatively. Relevance and novel information This case report describes an unusual feline nasal pathology. To our knowledge, there are no previous reports of a non-neoplastic, non-inflammatory expansile feline nasal tumour. Also described are the CT and histological appearance of the mass, and the difficulties encountered obtaining the definitive diagnosis. Information regarding the prognosis following surgical removal of proliferative fibro-osseous lesions in cats is poor, especially from the nasal cavity where clean margins may well be impossible to obtain. In this case, surgical resection improved clinical signs and the cat remains well at 15 months post-procedure.

Computed tomographic characteristics of frontal sinus ossifying fibroma in a dog

“…14 Ossifying fibromas must be differentiated from other bony masses of the mandible, maxilla, and craniofacial bones, including osteomas, low-grade osteosarcomas, osteitis/osteomyelitis, fibrous osteodystrophy, and multilobular tumor of bone. 1,2 Imaging features can be used to help a pathologist distinguish between ossifying fibromas and fibrous dysplasia within the oral cavity when histopathology alone is inconclusive. For instance, Soltero-Rivera et al 1 reviewed canine biopsy specimens of benign fibro-osseous lesions in conjunction with imaging findings, and six of nine cases that had originally been diagnosed as ossifying fibroma were re-classified as either fibrous dysplasia or low-grade osteosarcoma.…”

“…They are classified as benign fibro‐osseous lesions. Disorders within this group are characterized by a proliferative fibrous matrix that replaces normal bone, with variable amounts of mineralization and ossification present 2 . Fibrous dysplasia is another example of a benign fibro‐osseous lesion that is rarely diagnosed in dogs 1 .…”

“…Ossifying fibromas must be differentiated from other bony masses of the mandible, maxilla, and craniofacial bones, including osteomas, low‐grade osteosarcomas, osteitis/osteomyelitis, fibrous osteodystrophy, and multilobular tumor of bone 1,2 . Imaging features can be used to help a pathologist distinguish between ossifying fibromas and fibrous dysplasia within the oral cavity when histopathology alone is inconclusive.…”