Sézary syndrome in a cat

Sézary syndrome is an uncommon leukemic variant of cutaneous lymphoma in cats. This cat had recurrent dermatitis with erythematous, pruritic plaques. Multiple skin imprints and biopsy samples were obtained over a 6-month period, and histopathological findings were consistent initially with eosinophilic miliary dermatitis and later with erythema multiforme. One week before death, Sézary cells were identified in the peripheral blood that expressed cluster of differentiation (CD)3 and CD8 antigens. Massive infiltration of CD3+ lymphocytes was noted in the skin and multiple internal tissues by histopathological examination. This case demonstrates the difficulty in diagnosing cutaneous lymphoma early in the disease course.     

What is your diagnosis? Cervical mass in a cat

An 8-year-old female spayed domestic shorthair cat was presented for several months of weight loss, decreased appetite, and 2 bilateral, ventral cervical masses. Initial cytologic samples were interpreted as reactive lymphoid hyperplasia. Evaluation of subsequent mass aspirates revealed small numbers of large binucleated and multinucleated cells resembling Reed-Sternberg cells admixed with more numerous small and intermediate-sized lymphocytes. In histopathologic sections, the normal architecture of the lymph node was largely effaced by a slightly heterogeneous mass composed of round cells arranged in densely cellular sheets with a minor population of large (25-mum diameter) mononuclear cells and a few very large (30-40-mum diameter) binucleated or multinucleated cells interpreted as Reed-Sternberg-like cells. Immunohistochemically, the large neoplastic (Reed-Sternberg-like) cells were negative for CD18, CD3, CD20, and CD79a while the background population consisted of about 70% T cells and 30% B cells. This pattern of immunohistochemical staining along with cytologic and histopathologic findings supported a diagnosis of Hodgkin's-like lymphoma, specifically, the lymphocyte-rich subtype. Hodgkin's-like lymphoma has been reported previously in cats and should be suspected when Reed-Sternberg-like cells are observed in cytologic preparations of lymph node aspirates. Histopathology and immunohistochemistry are necessary for a definitive diagnosis.     

What is your diagnosis? Intracranial mass in a cat

Abstract: A 14‐year‐old female spayed cat was presented with a 3–4‐month history of circling to the left and intermittent head pressing. Neurologic examination findings localized the lesion to the left supratentorial region. Using magnetic resonance imaging, an extra‐axial mass was found on the dorsal aspect of the brain at the level of the frontal and parietal lobes, compressing and displacing the brain ventrally and caudally. Craniectomy was performed and the mass was submitted for cytologic and histopathologic evaluation. Impression smears revealed abundant cholesterol crystals and loose clusters of mildly pleomorphic spindle cells, compatible with a meningioma. The histopathologic diagnosis was meningioma with psammoma bodies and numerous cholesterol clefts. Abundant cholesterol crystals within meningiomas in cats may present a diagnostic challenge when nucleated cells are scant. Other differential diagnoses for abundant cholesterol crystals in an intracranial mass include cholesterol granulomas and keratinizing cysts.     

Transient myocardial thickening in a Bartonella henselae–positive cat

A 3-year-old castrated male domestic shorthair presented to the Cornell University Hospital for Animals for acute onset respiratory distress. Thoracic radiographs, echocardiogram, and electrocardiogram (ECG) revealed left-sided congestive heart failure, myocardial thickening with left atrial dilation, and sinus rhythm conducted with a left bundle branch block, respectively. Cardiac troponin I was elevated and continued to increase over 36 h (1.9 ng/mL, 3.1 ng/mL, and 3.5 ng/mL, sequentially every 12 h). The cat tested positive for Bartonella henselae and was treated with azithromycin (30 mg/kg by mouth (PO) every 24 h for 30 days), along with furosemide (1 mg/kg PO every 24 h), benazepril (0.4 mg/kg PO every 24 h), pimobendan (0.23 mg/kg PO every 12 h), and clopidogrel (18.75 mg PO every 24 h). Reevaluation at 6 weeks revealed normal respiratory rate on physical examination, normal cardiac structures and function on echocardiogram, resolution of left bundle branch block on ECG, and normal cardiac troponin I levels (0.06 ng/mL). All medications were discontinued at this time, and the cat continued to do well 5 months after reevaluation. Here, we report a case of transient myocardial thickening in a cat that was also positive for B. henselae.     

Intraocular ALλ amyloidoma with plasma cell neoplasia in a cat

An 11-year-old, neutered male domestic short-hair cat was presented with buphthalmos of the right eye and diagnosed with advanced glaucoma. Sonographic examination revealed an iridial thickening. Neoplasia was suspected and an enucleation was performed. Histopathology of the enucleated eye revealed abundant amyloid deposition predominantly in the anterior uveal tract accompanied by few to moderate numbers of well-differentiated plasma cells. The amyloid deposits were identified by staining with Congo red and showing green birefringence under polarized light. Immunohistochemically, amyloid and plasma cells stained intensely only with anti-ALλ antibody, supporting the amyloid tumor being an immunoglobulin-λ-light chain origin. Additional abnormalities included narrowing of the filtration angle and collapse of the ciliary cleft, and trabecular meshwork. One year post-enucleation, the cat was still healthy without signs of systemic amyloidosis or apparent metastatic disease. This is the first report of a cat with noncutaneous extramedullary plasmacytoma originating in the anterior uveal tract with resulting local amyloid.