No abstract

Papillomavirus-induced papillomas were diagnosed on multiple digits of all 4 feet of a young Beagle. No other cutaneous or oral involvement was identified. Papillomavirus antigen was confirmed by immunoperoxidase localization within keratinocyte nuclei. In addition to the typical basophilic intranuclear inclusions associated with papillomavirus infections, keratinocytes within the papillomas contained large, eosinophilic cytoplasmic inclusions that previously have been described in a Boxer with cutaneous lesions associated with a papillomavirus infection. The papillomas in this Beagle regressed completely within 2 months of the initial diagnosis.

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.

An 8-year-old castrated male Bichon Frise was presented to the Kansas State University Veterinary Health Center for evaluation of unilateral right-sided exophthalmos, suspected secondary to a retrobulbar abscess. The dog had acutely developed right-sided periorbital swelling, exophthalmos with pain on retropulsion, as well as multiple cutaneous exudative plaques on the feet and tail base. On ophthalmic examination, the dog also exhibited mild left-sided exophthalmos with decreased, nonpainful retropulsion. Orbital ultrasound and CT were performed to evaluate the extent of bilateral orbital disease. Incisional biopsies were obtained from the affected right periorbital tissues and skin of the feet, and histopathology revealed severe neutrophilic inflammation of the dermis with no organisms detected. Histologic changes were consistent with sterile neutrophilic dermatosis. The dog achieved clinical remission following treatment with initial immunosuppressive doses of corticosteroids and subsequent long-term maintenance therapy using oral cyclosporine.

A 2-yr-old, captive, intact female Virginia opossum ( Didelphis virginiana ) with a 7-mo history of ulcerative dermatitis and weight loss was euthanatized for progressive worsening of clinical signs. Initially the opossum was treated with several courses of antibiotics, both topically and systemically; systemic nonsteroidal anti-inflammatory medication; and, later, systemic glucocorticoids, with no improvement in clinical signs. Histopathologic samples of skin lesions taken 3 mo into the course of disease revealed no evidence of neoplasia; however, cytologic samples of a skin lesion taken 5 mo into the course of disease revealed mature lymphocytes, and were suggestive of cutaneous lymphoma. Postmortem histopathology revealed neoplastic cells consistent with lymphoma; these were found in the haired skin of the forearm, axilla, hind limb, face, and lateral body wall, as well as the liver, kidney, axillary lymph node, heart, and spleen. Multifocal neutrophilic and eosinophilic ulcerative and necrotizing dermatitis and folliculitis of the haired skin were also present. To the authors' knowledge, this is the first documented case of cutaneous lymphoma in a Virginia opossum and the first documented case with visceral metastases in a marsupial.