Presumptive paraneoplastic exfoliative dermatitis in four domestic rabbits

A seborrhoeic rabbit is a common diagnostic challenge, and ­differential diagnoses include malnutrition, ectoparasites, dermatophytosis, yeast dermatitis (White and others 2003), sebaceous adenitis (Jassies-van der Lee and others 2009, White and others 2000b), cutaneous lymphoma (White and others 2000a), autoimmune hepatitis-­associated (Florizoone and others 2007) and thymoma-associated exfoliative dermatitis (Florizoone 2005). The clinical observation of exfoliative dermatitis and histologic changes of lymphocytic mural and interface dermatitis and absence of sebaceous glands should prompt the clinician to search for a systemic cause with thymic neoplasia representing one of the top differentials. Our goal was to report on the historical and clinical progression, as well as the diagnostic and therapeutic alternatives used in four rabbits with exfoliative dermatitis associated with a mediastinal tumour. ### Case 1 A seven-and-a-half-year-old male castrated rabbit, 1.4 kg, was presented with a history of non-pruritic progressive hair loss, scaling, depression and weight loss over the previous 1.5 months. Dermatologic examination revealed multifocal alopecia and hypotrichosis, erythema, severe scaling and follicular casts. Multiple deep and superficial skin scrapings, acetate tape impression smears, trichograms and a fungal culture were negative for parasites, bacteria and fungi. Dermatopathological examination revealed severe epidermal orthokeratosis and mild, multifocal, lymphocytic ­exocytosis and a severe lymphocytic mural and interface folliculitis with absent sebaceous glands (Fig 1). Radiographs and ultrasound revealed a large mass in the cranial thorax cranial to the heart base, respectively. Cytology of fine needle aspirates showed them to contain predominantly lymphoblasts suggestive of …