Skin lesions in canine leishmaniasis

Forty-three dogs affected by canine leishmaniasis (CL) with skin lesions have been studied clinically and histopathologically. Identification of leishmaniads in tissues was achieved using indirect immunoperoxidase staining. According to both macroscopic and microscopic lesions, four different dermatological patterns have been observed. Twenty-six dogs showed alopecia and desquamation as the main skin lesions. Histologically a diffuse non-suppurative dermatitis, with numerous leishmaniads inside macrophages was present. Ten animals showed skin ulcerations on limbs, especially over articulations. Histologically, the number of leishmaniads was very reduced. Five animals presented a generalised nodular disease. Each nodule corresponded with a focal accumulation of macrophages, multinucleated giant cells and lymphocytes, with a high number of parasites. Finally, two dogs presented generalised skin pustules. The possible pathogenesis and the differential diagnosis of each form is discussed.     

Identification of canine T-lymphocyte subsets with monoclonal antibodies.

A panel of five murine monoclonal antibodies to canine T-lymphocytes were produced. Antibodies 4.78, 12.125 and 8.358 reacted with approximately 18%, 39% and 60% peripheral blood lymphocytes, respectively. Two color flow cytometric analysis showed that lymphocytes expressing 1.140, 4.78, 8.53 and 12.125 were subsets of lymphocytes expressing 8.358. The lymphocytes expressing 8.358 were negative for surface immunoglobulin. The subsets defined by 1.140, 4.78 or 8.53, 12.125 were mutually exclusive and together account for most cells expressing 8.358 in the peripheral blood, spleen, and lymph node. In the thymus, approximately 47% cells were positive for both 1.140/4.78 and 8.53/12.125. SDS-PAGE analysis of radiolabelled thymus cell lysates demonstrated that antibodies 1.140 and 4.78 immunoprecipitated a 32,35 kd heterodimer under reducing conditions and 12.125 immunoprecipitated a single 56 kd chain under reducing and non-reducing conditions. Antibodies 8.53/12.125 and 1.140/4.78 react with canine lymphocyte populations that occur in proportions similar to lymphocytes expressing CD4 and CD8 like molecules in several primate and non-primate species. The molecules recognized by 12.125 and 1.140/4.78 were similar in size and subunit composition to human CD4 and CD8.     

Extrapulmonary granulomatous lesions in canine paragonimiasis

Extrapulmonary granulomatous lesions associated with a naturally acquired Paragonimus kellicotti infection were observed in a dog with severe pulmonary paragonimiasis. Lung lesions were similar to those previously described. Extrapulmonary granulomatous lesions were found in the liver, mediastinal lymph nodes, spermatic cord and the tunica vaginalis. Extravascular deposition of eggs in the spermatic cord and tunica vaginalis caused a perilymphatic granulomatous inflammation and partially occlusive lymphangitis with dilatation of the external lymphatic vessel of the right spermatic cord.     

Comparison of T-lymphocyte proliferation in canine epitheliotropic lymphosarcoma and benign lymphocytic dermatoses

The lesions of patch/plaque cutaneous T-cell lymphosarcoma (CTCL) are similar to many benign inflammatory dermatoses, both histopathologically and clinically. In humans, attempts to develop a simple, reliable immunophenotypic technique to differentiate between the malignant and benign dermatoses have been unsuccessful. The purpose of our study was to determine, using a proliferating cell nuclear antigen (PCNA)/CD3 double immunolabelling technique of paraffin-embedded sections, if the rate of T-cell proliferation in canine CTCL was greater than that of other diseases with non-neoplastic lymphocyte epitheliotropism. We selected cases of patch/plaque (PP) and tumour stage CTCL, erythema multiforme (EM) and cutaneous lupus erythematosus (CLE). We did not find a significant difference in the rate of T-cell proliferation in the epithelia nor the superficial dermis between PP-CTCL and EM. Whereas epithelial T-cell proliferation is significantly higher in PP-CTCL than CLE, it is not diagnostically useful because of overlap in the labelling indices.     

Synovial lesions in experimental canine Lyme borreliosis

Borrelia burgdorferi is the causative agent of Lyme disease, which is mainly characterized by lameness in dogs. More than 95% of naturally infected dogs are asymptomatic or subclinical; however, in experimental studies, histologic synovial lesions are consistently observed in asymptomatic dogs inoculated with B. burdgorferi. This study investigates the ability of a synovial histopathologic scoring system, clinicopathologic data, and polymerase chain reaction (PCR) testing to differentiate between B. burgdorferi-infected and uninfected dogs. Eighteen 18-week-old beagles were subject to challenge with B. burgdorferi-infected wild-caught ticks (Ixodes scapularis), and 4 uninfected dogs served as controls. Infection was confirmed by serology (ELISA) and PCR amplification of B. burgdorferi-specific DNA of skin biopsies taken at the tick attachment site. A synovial scoring system from human medicine was adapted and implemented on postmortem synovial samples to discriminate infected and noninfected animals. Application of this system to elbows and stifles with a cumulative joint score cutoff > 4 showed a sensitivity of 88.2% and a specificity of 100%, with a positive likelihood ratio of infinity and a negative likelihood ratio of 0.12. Complete blood count, serum biochemistry, urinalysis, urine protein:creatinine, urine PCR, synovial and lymph node cytology, and synovial PCR were evaluated but were not reliable indicators of clinical disease.     

Nodular lesions of the tongue in canine leishmaniosis

In this case report, an atypical clinical presentation of leishmaniosis in a dog with multiple nodular lesions of the tongue is described. Haematological and biochemical analysis, serological test for Leishmania infantum antibodies and biopsy samples from several nodules of the tongue for histopathological examination were made. The final diagnosis of leishmaniosis was based upon the observation of amastigotes in the bioptic samples. It is recommended to consider leishmaniosis among the list of differentials of mucosal nodular lesions, at least in endemic areas.     

Review cutaneous lesions of the canine scrotum

Scrotal lesions are uncommon and often present a diagnostic challenge. In the veterinary literature there are no texts devoted to this subject. This study reviews and illustrates canine scrotal lesions following an aetiological layout with the aim of facilitating clinical identification and diagnosis. Infectious, immune-mediated, endocrinological and neoplastic conditions are the most commonly reported causes of scrotal lesions in the dog. They may affect the scrotum only or other parts of the body as well. The clinical presentation of the lesions, the presence of primary or secondary lesions and the presence of clinical signs of systemic disease may help in obtaining a diagnosis. In some cases further investigations are necessary to reach a definitive diagnosis. Histopathology aids in understanding pathological reactions of the scrotal skin but unfortunately this is not commonly carried out and few reports in the literature include histopathology. The list of conditions given in this review is not exhaustive and other, more rare, diseases may be encountered.     

Ocular lesions associated with coccidioidomycosis in dogs: 35 cases (1980-1985)

Thirty-five dogs with ocular lesions associated with coccidioidomycosis were examined. Serologic and/or histologic evaluation confirmed the diagnoses of coccidioidomycosis. The disease most frequently associated with signs referable to the anterior segment of the eye, such as iritis and granulomatous uveitis. Histologic evaluation of the eye revealed a primary posterior segment disease, such as chorioretinitis or retinal separation, with an extension into the anterior segment of the eye.     

Magnetic resonance imaging characterization of canine splenic lesions

Introduction:  Splenic lesions are a common finding in veterinary medicine and typically 1/2 to 2/3 of these lesions are malignant. Due to the limited accuracy of ultrasound, unnecessary exploratory surgeries/biopsies may be performed for benign lesions and treatment may be delayed for malignant ones. Splenic lesions are rare in people. MR imaging, with its inherently high soft tissue contrast, is efficacious in imaging the human spleen. We have previously demonstrated the efficacy of MRI to differentiate canine hepatic lesions. In that study 8 splenic lesions were all accurately characterized. This current study represents a further evaluation of splenic lesions.
Methods:  In this prospective study, 27 dogs with splenic lesions were accrued. Histopathological/cytological confirmation of lesions occurred either before or shortly after imaging. MRI clinicians were blinded to histopathology results. MR (General Electric, 1.5 Tesla) images using a variety of sequences were obtained before and after intravenous administration of gadolinium.
Results:  32 lesions (9 malignant, 23 benign) were evaluated in 27 dogs. Lesions were confirmed via histopathology (n = 20) or cytology (n = 12). Benign lesions included, EMH (n = 7), hematoma/hemorrhage (n = 5), lymphoid hyperplasia (n = 9), and hemangioma (n = 2). Malignant lesions included anaplastic sarcoma (n = 3), malignant histiocytosis (n = 2), hemangiosarcoma (n = 2), plasma cell tumor (n = 1) and adenocarcinoma (n = 1). The overall accuracy in differentiating benign from malignant lesions was 88%(29/32 lesions). The overall sensitivity and specificity were 100%(95% CI, 66–100) and 87%(95% CI 66–97).
Conclusions:  Based upon these results, MRI is both sensitive and specific in distinguishing between malignant and benign splenic lesions.     

Matrix metalloproteinase mRNA expression in canine anal furunculosis lesions

Although the aetiology of anal furunculosis (AF) in dogs is poorly understood, there is evidence for an underlying immune dysfunction. This is illustrated by the presence of a T helper type 1 cytokine mRNA profile in AF lesions and the clinical response to ciclosporin therapy. Expression of MMPs 2, 9 and 13 were evaluated in AF lesional biopsies by real-time quantitative RT-PCR. There was significantly increased expression of both MMP-9 and MMP-13 mRNA in AF biopsies compared to controls (p<0.001) but no significant difference in MMP-2 mRNA expression. Since MMP-9 and MMP-13 are primarily produced by macrophages, these data suggest that ulceration could be the result of aberrant activation of this cell type in the tissues. It is feasible that such pathological macrophage activity occurs in response to interferon-gamma secreted by T helper type 1 cells. This could explain why the lesions resolve following treatment with the immunosuppressive drug ciclosporin.