Radiographic bone lesions are uncommon in cats with MRD and extramedullary presentation is common, relative to human myeloma.

Abstract. Feline myeloma-related disorders (MRD) are rare neoplasms of plasma cells. The multistep transformation model of myeloma in humans is based on the premise that plasma cells undergo neoplastic transformation primarily within the intramedullary compartment and that over time they become poorly differentiated and metastasize to extramedullary locations. Historically, diagnostic criteria used for human multiple myeloma have been applied to the cat, with the assumption that feline MRD commonly arises in the intramedullary compartment. Our objectives were to describe the features of feline MRD confirmed by cytology, histopathology, histochemistry, and immunohistochemistry and to categorize these tumors. A priori hypotheses were 1) tumor category predicts survival and 2) cats with well-differentiated tumors commonly have extramedullary involvement in contrast to human myeloma patients. This multicenter, retrospective study identified 26 MRD cases. There was good agreement between histopathologic and cytologic tumor categorization. Histochemistry and immunohistochemistry were shown to be valuable adjunct tests in the diagnosis of MRD. Cats with well-differentiated tumors had increased median survival relative to those with poorly differentiated tumors (254 versus 14 days). We have reported that marked extramedullary involvement at initial clinical presentation is significantly more common in the cat than in human MRD patients. In this study, we demonstrate that cats with welldifferentiated tumors more commonly have extramedullary involvement than human myeloma patients with well-differentiated tumors (90% versus 20%, P , 0.0002). These results contrast strongly with the human myeloma model of primary intramedullary neoplastic transformation and suggest that primary extramedullary neoplastic transformation may be more common in feline MRD.

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This retrospective survey was undertaken between 2002 and 2007 on samples from dogs residing in Grenada. The objectives of the study were to identify the most common histologic types of canine cutaneous tumors, determine the relative frequency of each tumor type, and compare results to reports from other regions. In a series of 225 skin masses examined, the proportion of neoplasms was 72% whereas nonneoplastic tumors accounted for 15.6%, and inflammatory conditions constituted 12.4%. There were 10 types of nonneoplastic tumors with hamartomas being the most common (28.5%), followed by sebaceous hyperplasia (25.7%) and fibroepithelial polyps (22.8%). The 10 most common cutaneous neoplasms were hemangiosarcomas (19.1%), histiocytomas (8.6%), melanocytomas (8%), mast cell tumors (6.8%), lipomas (6.8%), hemangiopericytomas (6.2%), papillomas (5.6%), fibrosarcomas (5.6%), hemangiomas (4.9%), and squamous cell carcinomas (4.3%). Tumors of vascular origin and transmissible venereal tumors were more common in dogs in our study than reported from other regions.

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 5 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.

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.

Lethal acrodermatitis (LAD) is a genetically determined metabolic disease of bull terriers first described in the USA in the 1980s. In this study, the largest so far reported, 28 bull terriers born in the UK were diagnosed as suffering from LAD, and the clinical findings and the progression of the disease with time are described. The main characteristics of LAD are stunting, splayed digits, eating difficulties, skin disease of the face and feet, and increased susceptibility to microbial infections. In older dogs, paronychia, nail disease and hyperkeratosis of the footpads develops, becoming severe in dogs over six months of age. A diagnosis of LAD can be strongly suspected in any bull terrier showing a combination of the aforementioned signs from an early age. Dermatohistopathological demonstration of marked parakeratotic hyperkeratosis is strongly supportive of the diagnosis of LAD and, in association with the typical clinical findings, is sufficient to confirm a diagnosis. Although many of the clinical signs and the pathology of this condition suggest zinc deficiency, the measurement of blood zinc levels as a diagnostic aid is of limited value.

An 18-month-old Siamese cat, under treatment with cimetidine, developed an exfoliative dermatitis involving the ears, face and feet. Foot-pad lesions and paronychia with a caseous exudate were also present. Histopathology of skin biopsies showed subcorneal pustules involving the hair follicles. These findings were suggestive of pemphigus foliaceus. However, the presence of cutaneous vasculitis and the results of immunofluorescence testing did not support this diagnosis. Skin lesions disappeared when cimetidine treatment was stopped and reappeared with its re-use. A diagnosis of drug eruption was made. R E F E R E N C E S AUSTIN, V.H. (1976) Selected cases from my dermatology practice.