Marginal zone lymphoma in a dog.

A 13-year-old spayed female American Cocker Spaniel was presented for evaluation of a cough and weight loss. Physical exam revealed generalized lymphadenopathy. The patient was diagnosed with marginal zone lymphoma (MZL) on histopathology of an extirpated lymph node. This report demonstrates an unusual case of a pleomorphic neoplastic population documented on cytologic evaluation that had moncytoid features and peripheral blood involvement; a previously undocumented IgG1 monoclonal gammopathy was also an interesting feature of this canine MZL. The patient did not undergo chemotherapy for lymphoma and was euthanized over 4 years after the initial presentation.

Cutaneous lymphoid hyperplasia mimicking cutaneous lymphoma in a hyperthyroid cat.

A 12-year-old neutered male domestic shorthair cat presented for chronic, localized, swelling and crusting of the left upper lip, weight loss, sporadic vomiting, and focal alopecia between the scapulae was diagnosed with hyperthyroidism and regional eosinophilic lymphadenitis. Treatment with methimazole exacerbated an underlying hypersensitivity disorder leading to marked generalized lymphadenopathy that histologically mimicked lymphoma.

Hyperplasie lymphoïde cutanée imitant un lymphome cutané chez un chat hyperthyroïdien. Un chat commun domestique mâle stérilisé âgé de 12 ans qui a été présenté pour de l'enflure et un encroûtement chroniques et localisés sur la lèvre supérieure gauche, une perte de poids, des vomissements sporadiques et de l'alopécie focale entre les omoplates a été diagnostiqué avec de l'hyperthyroïdisme et une lymphadénite à éosinophiles régionale. Le traitement au méthimazole et peut-être une hypersensibilité sous-jacente ont induit une lymphadénopathie généralisée marquée qui imitait histologiquement le lymphome.(Traduit par Isabelle Vallières).

Positive immunostaining for feline infectious peritonitis (FIP) in a Sphinx cat with cutaneous lesions and bilateral panuveitis.

Feline infectious peritonitis (FIP) is a common, fatal, systemic disease of cats. This case report describes the antemortem diagnosis of FIP in a 2-year-old spayed female Sphinx cat that presented with a bilateral panuveitis and multiple papular cutaneous lesions. Histopathologically, the skin lesions were characterized by perivascular infiltrates of macrophages, neutrophils, with fewer plasma cells, mast cells, and small lymphocytes in the mid- to deep dermis. Immunohistochemistry for intracellular feline coronavirus (FeCoV) antigen demonstrated positive staining in dermal macrophages providing an antemortem diagnosis of a moderate, nodular to diffuse, pyogranulomatous perivascular dermatitis due to FIP infection. Obtaining an antemortem diagnosis of FIP can be a challenge and cutaneous lesions are rare in the disease. Recognition and biopsy of any cutaneous lesions in cats with panuveitis and suspected FIP can help establish an antemortem diagnosis of the disease.

Central nervous system blastomycosis in a dog.

An adult golden retriever was presented for progressive neurologic dysfunction. Clinical examination suggested brainstem disease. Blastomycosis was diagnosed based on fine-needle aspiration cytology of a normal sized lymph node and a positive blastomycosis urine antigen test. Systemic blastomycosis with neurologic involvement was confirmed at necropsy.

Cytokeratin and vimentin co-expression in 21 canine primary pulmonary epithelial neoplasms.

Co-expression of cytokeratin and vimentin has been traditionally associated with a few select tumors. However, this phenomenon is being recognized in a wider range of tumors. Twenty-one canine primary pulmonary epithelial neoplasms were evaluated for the co-expression of cytokeratin and vimentin. The histologic pattern and grade, and an immunohistochemical grade for cytokeratin and vimentin staining, were determined for each neoplasm. Adenocarcinomas predominated, and histologically, most tumors were grade II. All of the neoplasms stained positive for cytokeratin, while only 8 (38%) stained positive for both vimentin and cytokeratin. Papillary adenocarcinomas were consistently vimentin negative. The anaplastic histologic pattern had significantly more vimentin staining than the other histologic patterns. There was no significant difference in histologic grade or grading criteria between those tumors that stained with vimentin and those that did not. The present study established that cytokeratin and vimentin co-expression occurs in canine primary pulmonary epithelial tumors at a similar frequency to human pulmonary neoplasms. Further investigation will be needed to characterize the significance of this finding, particularly with respect to prognosis.

Immunoglobulin A multiple myeloma with cutaneous involvement in a dog.

An 8-year-old rottweiler, diagnosed with multiple myeloma and multiple sites of cutaneous involvement, was treated with chemotherapy and radiation therapy. The diagnostic criteria for canine multiple myeloma, limitations of diagnostic testing for light chain proteinuria in dogs, and the role of radiation therapy in multiple myeloma patients is discussed.