Histological changes in the external ear canal of dogs with otitis externa.

This study aimed to better characterise the gross anatomy of the normal ear canal, and to compare histological features of the normal ear canal to those affected by chronic otitis externa. In 40 normal ears from 20 dogs, the length of the annular and auricular cartilage was 1.2 +/- 0.2 and 4.1 +/- 0.9 cm, respectively; overall length of the external ear canal was 5.3 +/- 1.0 cm. The maximal internal diameter at the distal end of the external ear canal, the proximal opening of the auricular cartilage and the proximal end of the annular cartilage was 5.8 +/- 1.5, 0.7 +/- 0.2 and 0.5 +/- 0.1 cm, respectively. Body weight correlated positively with the overall length and diameter of the distal end of the ear canal (r = 0.78, P < 0.001; r = 0.42, P < 0.05). Morphometric evaluation was carried in 28 clinically healthy ears of 14 dogs, and 15 otitic ears of 13 dogs. Histological features of this integument revealed that the density and distribution of sebaceous and ceruminous gland tissue exhibits marked variation between individuals. Nevertheless, general patterns were observed; sebaceous tissue increases gradually from the proximal to the distal parts of the ear canal, whilst ceruminous gland tissue by contrast decreases. In otitic canine ears, the distribution of sebaceous and ceruminous glandular tissue was similar to normal ears but the glands became larger and hyperplastic (P < 0.05). Density of hair follicles was not different between healthy and otitic ears (P = 0.16), but the hair follicles became hyperplastic in otitic ears.

Solitary plasmacytoma of bone in two successfully treated cats.

This is the first report of feline solitary plasmacytoma of bone. We describe the clinical, clinico-pathological, radiographic and pathological findings of two successfully treated cats with long-term follow-up. The first case presented with spinal pain and neurological deficits. Radiographs demonstrated sclerosis of lumbar vertebra L6 and a myelogram confirmed interference to flow of contrast in the L4-7 region. A biopsy of L6 revealed neoplastic plasma cell infiltration. There was no evidence of paraproteinaemia on serum protein electrophoresis. The cat underwent hypofractionated megavoltage radiotherapy. Clinical signs resolved completely and 4 years after diagnosis the cat remains well and has no electrophoretically detectable paraproteinaemia. The second case presented with neurological deficits of the tail and spinal radiographs revealed extensive osteolysis of the sacrum. A biopsy of sacral bone demonstrated neoplastic plasma cell infiltration. The animal was normoglobulinaemic. The cat improved clinically with induction chemotherapy (melphalan and methylprednisolone). The same chemotherapeutics were continued at maintenance doses for 4.3 years, at which time there was recurrence of neurological deficits and a palpable sacral mass. Cytological examination of a fine needle aspirate confirmed recurrence of plasma cell neoplasia. A low concentration monoclonal paraproteinaemia was detected. Vincristine was administered resulting in resolution of neurological deficits and a palpably smaller sacral mass. Eighteen months into vincristine therapy, there was recurrence of clinical signs and the cat was euthanased, more than 6 years after the initial diagnosis.

Myeloma-related disorders in cats commonly present as extramedullary neoplasms in contrast to myeloma in human patients: 24 cases with clinical follow-up.

BACKGROUND: Myeloma-related disorders (MRD) are rare neoplasms of plasma cells. Published case reports describe a diversity of clinical presentations with confusing terminology and diagnostic criteria as a consequence of the assumption that MRD in cats are analogous to those in dogs or humans. OBJECTIVE: The aim of the study was to describe clinical, clinicopathologic and imaging findings, response to treatment, survival and possible associations with other diseases or vaccination in a large case series. A priori hypotheses were that cats with MRD commonly present with extramedullary involvement and uncommonly have radiographic bone lesions, in contrast to human patients. ANIMALS: Twenty-four cats with MRD confirmed by cytology or histopathology and immunohistochemistry. METHOD: A multicenter retrospective study was performed. RESULTS: Two types of clinical presentation were observed. The first group (n = 17) had neoplasia involving abdominal organs, bone marrow, or both. All developed systemic clinical signs and paraproteinemia. Five of 7 cats that received chemotherapy improved clinically or had decreased serum globulin concentration (median survival, 12.3 months; range, 8.5-22 months). The second group comprised 7 cats with skin masses, 2 of which were paraproteinemic and developed rapidly worsening systemic signs. In cats without systemic signs, excision of the skin masses appeared to be associated with prolonged survival (up to 2.4 years). Cats with MRD commonly presented with extramedullary involvement (67%), versus humans with MRD (5%) (P < .001), and uncommonly presented with radiographic bone lesions (8%) versus humans with MRD (80%) (P < .001). CONCLUSIONS: Radiographic bone lesions are uncommon in cats with MRD and extramedullary presentation is common, relative to human myeloma.

An analysis of factors underlying hypotrichosis and alopecia in Irish Water Spaniels in the United Kingdom.

A survey on the occurrence of dermatoses in the Irish Water spaniel (IWS) was carried out in the United Kingdom. A group of 20 dogs was selected and examined clinically. All dogs had a nonpruritic, noninflammatory, regionalized hair loss affecting the same areas of the body in males and females, although an initial cyclical pattern associated with the oestrus cycle was identified. Hormonal investigations showed features suggestive of an abnormality of steroidogenesis. Histopathology revealed features similar to canine recurrent flank alopecia (CRFA) and follicular dysplasia associated with abnormal melanization, as in colour dilution alopecia, although the clinical features did not correlate with those conditions. Dietary changes improved coat and skin quality in most of the cases in this series but the role of the diet was not investigated further. This study suggests that hair loss in IWS is influenced by dietary factors and sexual hormones. Abnormalities of the steroidogenic pathways may contribute to the severity of the condition.

A case of metabolic epidermal necrosis in a cat.

Abstract This report describes clinical, histological and post-mortem findings in a cat, that are similar to necrolytic migratory erythema in humans and to metabolic epidermal necrosis in dogs. Resumen Este articulo describe los hallazgos clinicos, histopatológicos y post mortem en un gato, similares a Eritema Necrolitico Migratorio en la especie humana y a Necrosis Epidérmica Metabólica en el perro. [Patel, A., Whitbread, J., McNeil. P. A case of metabolic epidermal necrosis in a cat. (Un caso de necrosis epidérmica en un gato.) Veterinary Dermatology 1996; 7: 221-226.] Résumé Ce cas décrit les lésions cliniques, histopathologiques et nécropsiques chez un chat, évoquant l'érythème nécrolytique migrant de l'homme et la nécrose épidermique métabolique du chien. [Patel, A., Whitbread, J., McNeil. P. A case of metabolic epidermal necrosis in a cat. (Un cas de nécrose épidermique métabolique chez un chat.) Veterinary Dermatology 1996; 7: 221-226.] Zusammenfassung Dieser Bericht beschreibt klinische, histopathologische und Sektionsbefunde bei einer Katze, die dem hekrolytischen migratorischen Erythem beim Menschen und der stoffwechselbedingten epidermalen Nekrose beim Hund ähneln. [Patel, A., Whitbread, J., McNeil. P. A case of metabolic epidermal necrosis in a cat. (Ein Fall von stoffwechselbedingter epidermaler nekrose bei der Katze) Veterinary Dermatology 1996; 7: 221-226.].