Cutaneous mastocytosis in 8 young dogs and review of literature.

Cutaneous mastocytosis (CM) is a rare condition in young dogs characterized by multicentric cutaneous proliferation of neoplastic mast cells. Clinical data from 8 dogs that met inclusion criteria (age of onset less than 1.5 years, greater than 3 lesions) were obtained via a standardized survey. Biopsy samples were classified by the Kiupel/Patnaik grading systems and analyzed for c-KIT mutations. The median age of onset was 6 months (range: 2-17 months). Dogs had 5 to more than 50 lesions characterized as nodules, plaques, and papules. Seven dogs were pruritic. Clinical staging in 2 dogs did not reveal visceral involvement. No dogs had systemic illnesses at diagnosis. Histologically, CM was similar to cutaneous mast cell tumor (cMCT). Two dogs had neoplasms classified as high-grade/grade II while 6 dogs had low-grade/grade II neoplasms. No dogs had mutations in c-KIT exons 8 and 11. Treatment included antihistamines (8/8), corticosteroids (7/8), lokivetmab (3/8), and toceranib (1/8). Six dogs were alive with lesions at the end of the study with a median follow-up time of 898 days, while 2 dogs were euthanized. In dogs with high-grade/grade II neoplasms, one continued to develop lesions at 1922 days post-diagnosis, while the other dog was euthanized at 56 days post-diagnosis. One dog was euthanized 621 days post-diagnosis due to rupture of a neoplasm. CM occurs in young dogs and is histologically indistinguishable from cMCT. Current histologic grading systems did not apply uniformly to the dogs of the study and further studies are needed.

Feline Pemphigus Foliaceus.

Feline pemphigus foliaceus is an uncommon skin disorder in cats but still the most common autoimmune skin disorder seen in this species. It is a crusting dermatosis involving the ears, head, paws, and ungual folds primarily. Although cytology is helpful in supporting a diagnosis, biopsy of pustules or crusts for histopathology is required for a definitive diagnosis. Therapy has evolved over the years as we have learned more about the different ways cats respond to drugs and as new drugs became available. Most cats will respond to proper therapy, although it may be needed long term for control.

Distribution of Malassezia organisms on the skin of unaffected psittacine birds and psittacine birds with feather-destructive behavior.

OBJECTIVE: To ascertain whether Malassezia organisms can be detected via cytologic examination and fungal culture of samples from the skin surface of psittacine birds and determine whether the number of those organisms differs between unaffected psittacines and those that have chronic feather-destructive behavior or differs by body region. DESIGN: Prospective study. ANIMALS: 50 unaffected psittacines and 53 psittacines that had feather-destructive behavior. PROCEDURE: Samples were collected by use of acetate tape strips from the skin of the head, neck, proventer, propatagium, inguinal region, and preen gland area of each bird; 0.5-cm(2) sample areas were examined microscopically for yeast, and samples were also incubated on Sabouraud dextrose agar. Polymerase chain reaction assays specific for Malassezia spp, saprophytic fungi, and Candida albicans were performed on DNA prepared from cultured colonies; nested PCR evaluation for Malassezia pachydermatis was then performed. RESULTS: Microscopically, 63 of 618 (10%) tape-strip samples contained yeast. Thirty cultured colonies were assessed via PCR assays, and all yielded negative results for Malassezia spp; C albicans was identified in 2 colony samples. The numbers of yeast identified microscopically in psittacines with feather-destructive behavior and in unaffected birds did not differ significantly, and numbers did not differ by body region. CONCLUSIONS AND CLINICAL RELEVANCE: Yeast were identified infrequently via cytologic examination of samples from the skin surface of unaffected psittacine birds or those that had chronic feather-destructive behavior. If yeast are identified on the skin of birds with feather-destructive behaviors, fungal culture of skin samples should be performed to identify the organism.

Multiple papillomavirus-associated epidermal hamartomas and squamous cell carcinomas in situ in a dog following chronic treatment with prednisone and cyclosporine.

A 4-year-old, spayed female toy fox terrier developed multiple epidermal hamartomas and squamous cell carcinomas in situ following chronic immunosuppressive therapy with prednisone and cyclosporine for management of an immune-mediated nonregenerative anaemia. Immunohistochemical staining was positive for papillomavirus antigen within both benign (n = 19) and malignant (n = 8) cutaneous lesions that developed during a 3-year period of observation, with positive staining most often seen in keratinocytes in the granular cell layer. Treatment of the papillomavirus infection with interferon-alpha was discontinued after 2 weeks because of diarrhoea and a further increase in liver enzymes. The cutaneous lesions of this dog persisted and new lesions developed during the year following discontinuation of both cyclosporine and prednisone. This is the first reported case of papillomavirus-associated squamous cell carcinoma in situ developing in a dog following chronic administration of cyclosporine and prednisone.

Heart failure caused by toxoplasmosis in a fennec fox (Fennecus zerda).

A male fennec fox (Fennecus zerda) kit was examined for lethargy, inappetence, and weight loss. Clinical findings included respiratory distress, a gallop rhythm, and retinochoroiditis. Radiography indicated pleural effusion and cardiomegaly. Echocardiographic findings included left ventricular dilatation, low left ventricular ejection fraction, and atrioventricular valvular regurgitation. Necropsy findings were compatible with a diagnosis of congestive heart failure caused by myocarditis. Histopathology showed a disseminated infection with Toxoplasma gondii causing myocarditis, skeletal polymyositis, gastrointestinal myositis, and panuveitis. Toxoplasma-induced myocarditis should be included in the differential diagnosis of heart failure and retinochoroiditis in the fennec fox.

Feline pemphigus foliaceus: a retrospective analysis of 57 cases.

Fifty-seven cases of feline pemphigus foliaceus were identified from biopsy specimens submitted to University of Pennsylvania School of Veterinary Medicine's Laboratory of Pathology and Toxicology by veterinary dermatologists from 1991 to 2002. Age at onset ranged from less than 1 year to 17 years; median 5 years. Eighty per cent of cats were reported to have been pruritic. At the time of biopsy, the distribution of lesions varied, but included some combination of face/head, paws, dorsum or ventrum and consisted of crusts, erosions, scale and alopecia. The histological features of 208 biopsy specimens were reviewed and included the following. Acantholytic cells were found in large numbers in both intact and degenerating pustules in most cases. Mast cells were found in the dermal infiltrate more often than reported previously. Seventeen cases were receiving corticosteroids at the time of biopsy; reducing the percentage of diagnostic biopsies per case. Forty-four cases were followed for 1-54 months (median 9 months). Triamcinolone was more successful at inducing remission without significant adverse effects than prednisone or prednisone in combination with chlorambucil. Only 4/44 cats died from their disease or therapy during the study period.

Measurement of body temperature by use of auricular thermometers versus rectal thermometers in dogs with otitis externa.

OBJECTIVE: To compare measurements of body temperature obtained with auricular thermometers versus rectal thermometers in dogs with otitis externa. DESIGN: Prospective study. ANIMALS: 100 client-owned dogs: 50 with and 50 without clinical evidence of otitis externa. PROCEDURE: Dogs were evaluated for the presence of otitis externa on the basis of clinical signs, otoscopic examination, and cytologic evaluation of ear exudate. Auricular and rectal temperatures were obtained simultaneously in all dogs prior to and following ear examination. RESULTS: There was a high correlation between auricular and rectal temperatures in dogs with otitis externa both prior to and after ear manipulation. Significant differences were not detected in temperature measurements among dogs with different degrees of otitis externa. CONCLUSIONS AND CLINICAL RELEVANCE: Auricular temperature readings obtained by use of an auricular thermometer in dogs with otitis externa are accurate measurements of body temperature, compared with rectal temperature measurements. Temperature measurements are reliable before and after examination of the ear canal.