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A retrospective study was undertaken to determine the prevalence of different diseases in cats referred for investigation of chronic nasal disease, to identify historical, clinical and diagnostic features which may assist in making a diagnosis, and to provide information pertaining to outcome in these cats. Diagnoses included neoplasia (30 cases), chronic rhinitis (27), foreign body (8), nasopharyngeal stenosis (5), Actinomyces infection (2), nasal polyps (2), stenotic nares (2), and rhinitis subsequent to trauma (1). The most common neoplasia was lymphosarcoma (21 cases), with a median survival of 98 days for cats treated with multiagent chemotherapy. Cats with neoplasia were older on average than the other cats, and were more likely to be dyspnoeic and have a haemorrhagic and/or unilateral nasal discharge than cats with chronic rhinitis. Cats with neoplasia were more likely to have radiographic evidence of nasal turbinate destruction, septal changes, or severe increases in soft tissue density than cats with chronic rhinitis. It was unusual for cats with diseases other than neoplasia to be euthanased as a result of their nasal disease.

This report details clinical, histopathological and immunohistochemical findings in 18 cats with chronic nasal disease diagnosed as nasal lymphoma. Eight of the cats were female and 10 were male, with a median age of 10.5 years (range 7-14 years). Three of the cats were Siamese, one was Burmese, and the rest were non-pedigree. The duration of clinical signs before referral ranged from 30 to 540 days (median 88.5 days). The most common clinical signs were nasal discharge, stertor and sneezing. Nasal radiographs were abnormal in 14/16 cases examined. Abnormal masses were detected endoscopically in 13/18 cases. Nine cats received multi-agent chemotherapy or radiation therapy, or both, with survival times ranging from 14 to >541 days. Biopsy material from these 18 cats was examined by light microscopy, and serial sections were subjected to immunohistochemical labelling for the T lymphocyte marker CD3 and the B lymphocyte marker CD79a. In 13 tissues, expression of class II molecules of the major histocompatibility complex and the myelomonocytic antigen MAC387 was also determined. Twelve of the tumours were classified as diffuse large B-cell lymphomas, four as lymphoblastic B-cell lymphomas, and one as a follicular B-cell lymphoma. The tumour cells within these lesions all expressed CD79a, and (where tested) most also expressed MHC class II. One tumour was an anaplastic large cell neoplasm, in which the neoplastic cells expressed MHC class II alone in the absence of either lymphoid marker. There was a variable infiltration of reactive small T lymphocytes into these tumours, and zones of necrosis within the tumour tissue were sometimes heavily infiltrated by MAC387+ phagocytic cells.

An 18-month-old domestic short-haired neutered male cat presented with a nodular dermal thickening on a digit. Biopsy demonstrated pyogranulomatous inflammation with moderately frequent acid-fast bacilli. A member of theMycobacterium terrae complex was isolated. There was no evidence of systemic involvement. Treatment was initiated with enrofloxacin, rifampicin and clarithromycin. After 2 months there was no longer any clinically apparent dermal thickening. Treatment was continued for a further 3 months using enrofloxacin and rifampicin.