Superficial necrolytic dermatitis in a dog with an insulin-producing pancreatic islet cell carcinoma.

A 10-year-old dog presented with convulsive crisis and symmetrical hyperkeratotic cutaneous lesions affecting the abdomen, inguinal area, eyelids, muzzles, both pinnae, and all the paw pads. Hypoglycemia and hyperinsulinemia were the main biochemical findings. A mass 2 cm in diameter was detected within the left pancreatic lobe by ultrasonography. It was surgically removed and histologically and immunohistochemically diagnosed as an insulin-producing pancreatic islet cell carcinoma. The animal was eventually euthanized due to lack of clinical improvement. At necropsy, metastatic nodules were observed in the pancreatic lymph nodes and liver. Histopathological findings of cutaneous lesions were highly suggestive of superficial necrolytic dermatitis and were interpreted as a paraneoplastic syndrome derived from the islet cell carcinoma. To the authors' knowledge, this is the first report of superficial necrolytic dermatitis associated with an insulin-producing pancreatic neuroendocrine carcinoma in dogs.

Development of a PCR technique specific for Demodex injai in biological specimens.

The identification of Demodex injai as a second Demodex species of dog opened new questions and challenges in the understanding on the Demodex-host relationships. In this paper, we describe the development of a conventional PCR technique based on published genome sequences of D. injai from GenBank that specifically detects DNA from D. injai. This technique amplifies a 238-bp fragment corresponding to a region of the mitochondrial 16S rDNA of D. injai. The PCR was positive in DNA samples obtained from mites identified morphologically as D. injai, which served as positive controls, as well as in samples from three cases of demodicosis associated with proliferation of mites identified as D. injai. Furthermore, the PCR was positive in 2 out of 19 healthy dogs. Samples of Demodex canis and Demodex folliculorum were consistently negative. Skin samples from seven dogs with generalized demodicosis caused by D. canis were all negative in the D. injai-specific PCR, demonstrating that in generalized canine demodicosis, mite proliferation is species-specific. This technique can be a useful tool in the diagnosis and in epidemiologic and pathogenic studies.

Immunohistochemical detection of COX-2 in feline and canine actinic keratoses and cutaneous squamous cell carcinoma.

Cyclooxygenase-2 (COX-2) overexpression and its causal role in epidermal carcinogenesis have been demonstrated in human actinic keratoses (AK) and cutaneous squamous cell carcinoma (SCC). The aim of this study was to determine immunohistochemically the level of expression of COX-2 in feline and canine AK (n=18), SCC (n=36) and inflammatory dermatoses (n=24). COX-2 immunoreactivity was detected in all feline and canine SCC. In all specimens, labelled basal and suprabasal neoplastic keratinocytes were localized within and below areas of superficial erosion or ulceration and only scattered deeper tumour cells were positively labelled. In most cases, positive immunoreactivity of keratinocytes was associated with the presence of granulocytes. COX-2 expression was detected in 3/9 canine and 4/9 feline cases of AK and in only one case was associated with inflammation. Inflammatory dermatoses were characterized by positively labelled epidermal and follicular basal and suprabasal keratinocytes that were always associated with granulocyte exocytosis. These results indicate that further study of the effect of using COX-2 inhibitors in the management and prevention of feline and canine cutaneous SCC is warranted. The association between inflammatory cells and COX-2 expressing epidermal cells opens a new line of research regarding the role of COX-2 in SCC oncogenesis. Moreover, further studies should investigate the role of COX-2 in the pathogenesis and management of AK in animals.

Acral mutilation syndrome in a miniature pinscher.

Acral mutilation syndrome (AMS) is a rare canine hereditary sensory neuropathy that results in progressive mutilation of the distal extremities and which has been reported only in German short-haired pointers, English pointers, English springer spaniels and French spaniels. The present report describes a case of AMS in an 18-month-old female miniature pinscher with progressive self-mutilation of the hind feet. The dog did not respond to any treatment and was humanely destroyed at the age of 30 months. Microscopical findings post mortem were restricted to the nervous system and were compatible with AMS. This is the first case of AMS described in a miniature pinscher. It is not known if the disease was the result of a point mutation in this particular dog or if the miniature pinscher breed will evolve to become a breed predisposed to AMS.

Dermatophagoides farinae-specific immunotherapy in atopic dogs with hypersensitivity to multiple allergens: a randomised, double blind, placebo-controlled study.

A randomised, placebo-controlled, double blind study was conducted on 25 dogs that had atopic dermatitis, together with skin test reactivity and elevated serum IgE to Dermatophagoides farinae (Df) and at least one additional allergen. Dogs were treated with either a Df-restricted immunotherapy solution (n=14) or a placebo (n=11) and evaluated 6 weeks and 3, 5, 7 and 9 months after the initiation of treatment using a clinical scoring system (SASSAD) and pruritus analogue scale scores. The Df-restricted solution and the placebo had an equal effect on both pruritus and the skin manifestations (P>0.05). The results of this study indicate that in dogs with atopic dermatitis based on hypersensitivity to environmental allergens in addition to D. farinae, Df-restricted immunotherapy is insufficient to control the disease. Consequently, a solution for allergen-specific immunotherapy should remain customised.

Cutaneous mucinosis in shar-pei dogs is due to hyaluronic acid deposition and is associated with high levels of hyaluronic acid in serum.

Cutaneous mucinosis affects primarily shar-pei dogs. Hyaluronic acid (HA) is considered to be the main component of mucin and CD44 is the major cell surface receptor of HA, necessary for its uptake and catabolism. The aims of this study were to identify the composition of the mucin in cutaneous mucinosis of shar-pei dogs, investigate the correlation between the deposition of HA and the expression of CD44, and determine whether shar-pei dogs with cutaneous mucinosis presented with elevated levels of serum HA. In skin biopsies, the mucinous material was stained intensely with Alcian blue and bound strongly by the hyaluronan-binding protein. No correlation was found between the degree of HA deposition in the dermis and the expression of CD44 in the skin of shar-pei dogs affected or unaffected by cutaneous mucinosis. A clear positive correlation was found between the existence of clinical mucinosis and the serum HA concentration. In control dogs, serum HA ranged from 155.53 to 301.62 microg L(-1) in shar-pei dogs; without mucinosis it ranged from 106.72 to 1251.76 microg L(-1) and in shar-pei dogs with severe mucinosis it ranged between 843.51 to 2330.03 microg L(-1). Altogether, the results reported here suggest that mucinosis of shar-pei dogs is probably the consequence of a genetic defect in the metabolism of HA.

Neutrophilic dermatosis resembling pyoderma gangrenosum in a dog with polyarthritis.

This report describes a case of neutrophilic dermatosis in a dog, with a number of clinical and pathological similarities to human pyoderma gangrenosum. A seven-year-old, female German shepherd dog with a history of non-erosive idiopathic polyarthritis was presented with severe facial swelling, bilateral erosivoulcerative lesions on the muzzle and multiple, eroded, dermal-subcutaneous nodules on the cranial trunk. Histopathological examination of skin biopsies revealed a necrotising neutrophilic dermatitis. No infectious agents could be detected using specific stains, immunohistochemistry, serology and bacterial aerobic, anaerobic or fungal cultures. A sterile neutrophilic dermatosis resembling human pyoderma gangrenosum was presumptively diagnosed, and the patient showed an excellent response to treatment with prednisone and ciclosporin.