A local breed of buffalo, Murrah cross 4.5 years old with a tumor on its forelimb of left leg on the lateral side of metacarpal, suspected as squamous cell carcinoma is discussed in this study. As primary sign animal showed awkward gait and difficulty in movement. Initially the mass was seen as wart like structure and later on progressed to the formation of bulky mass of cancerous cells in the span of three months. The attempt to treat by chemotherapy was unsuccessful during the course. The tumor was surgically removed after fine needle aspiration cytology. Histopathological examination performed on the removed mass showed underlying acanthosis and hyperkeratosis. Thus, the case was confirmed as squamous cell carcinoma. Post-operative care was provided to the animal after the surgery. The main aim of this study was to differentiate the nature and type of tumor and to provide a way to further proceed the treatment in similar cases.

Currently, prognostic and therapeutic determinations for canine cutaneous mast cell tumors (MCTs) are primarily based on histologic grade. However, the use of different grading systems by veterinary pathologists and institutional modifications make the prognostic value of histologic grading highly questionable. To evaluate the consistency of microscopic grading among veterinary pathologists and the prognostic significance of the Patnaik grading system, 95 cutaneous MCTs from 95 dogs were

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Radical first excision of presumed VAS is essential for extended TFR. Current recommendations for vaccination of the distal portions of the extremities are appropriate, because this practice permits radical excision of tumors (amputation) that develop at vaccination sites; however, surgery alone is seldom curative.

Recently, we reported an increased incidence of soft tissue sarcomas in a biopsy population of cats at the University of Pennsylvania School of Veterinary Medicine.8 Epidemiologic evidence indicated that this increase coincided with enactment of a Pennsylvania state law requiring rabies vaccination of cats, and the majority of these sarcomas were in areas routinely used by veterinarians for vaccination (dorsal neck/ interscapular, dorsolateral thorax, hindlimb, dorsal lumbar). Many of the sarcomas were surrounded and partially infiltrated by an inflammatory infiltrate of lymphocytes and macrophages. A similar inflammatory infiltrate had previously been reported to occur subsequent to subcutaneous injection of rabies vaccines in cats and dogs.' Furthermore, aluminum was identified in macrophages surrounding the sarcomas by electron probe x-ray microanalysis. Aluminum, in the form of aluminum hydroxide or aluminum phosphate, is an adjuvant in approximately 20% of vaccines for feline use. It was our interpretation that persistence of the inflammatory and immunologic reactions associated with the presence of the aluminum in the vaccination sites predisposes the cat to a derangement of its fibrous connective tissue repair response, occasionally leading to neoplasia. It is now apparent that vaccine-associated sarcomas are being recognized throughout the United S t a t e~.~. '~ Here we describe the histology and immunohistochemical marker staining of postvaccinal sarcomas. We hope this will increase the recognition of these sarcomas by pathologists and shed some light on the pathogenesis of this intriguing syndrome.The information presented here is based on 46 feline sarcomas in the surgical pathology files of the School of Veterinary Medicine of the University of Pennsylvania. These sarcomas were received during 1991 and 1992 and were documented by Veterinarians responding to an epidemiological survey to have occurred at sites at which there had been previous vaccination (unpublished data). Sarcomas were fixed in 10% formalin and routinely processed for histologic examination. Five-micrometer sections were cut from paraffinembedded blocks and stained with hematoxylin and eosin. A previously described avidin-biotin immunoperoxidase complex technique was used on representative sarcoma^.^ Briefly, paraffin-embedded sections, 5 pm in thickness, were cut and carefully melted at 58-60 C. After deparaffinization and rehydration, slides were incubated in 0.3% H 2 0 2 in absolute methanol for 45 minutes. Sequential incubations in 20% normal goat serum (30 minutes), primary antiserum (1 hour at room temperature or overnight at 4 C), secondary biotinylated antibody (45 minutes), and avidin-biotin complex reagent (45 minutes) followed. Sections were then exposed to the chromagen reaction solution (0.035% diaminobenzidine in 10 ml Tris buffer, filtered, and brought to 0.03% H202) for 5 minutes. Sections were counterstained in Mayer's hematoxylin, dehydrated, cleared, and mounted.For certain antisera (see below), sections were pretr...

BACKGROUND Pet dogs and men share a vulnerability for the development of prostate carcinoma. The purpose of this study was to further characterize the clinical and pathologic features of spontaneous canine prostate carcinoma. METHODS A multiinstitutional, retrospective study was conducted using 76 dogs with prostate carcinoma that underwent postmortem evaluation. For each case, clinical and pathologic data were tabulated and hematoxylin/eosin‐stained tissue sections from the primary tumor and metastatic lesions were evaluated. Prostatic carcinomas were subclassified based upon the presence of glandular, urothelial, squamoid, or sarcomatoid differentiation. We focused our analysis on dogs that differed with respect to morphologic features of the primary tumor, lifetime duration of testicular hormone exposure, and presence of skeletal metastases. RESULTS The vast majority of canine prostate carcinomas affected elderly sexually intact dogs or dogs that underwent surgical castration after sexual maturity. Adenocarcinoma was the most frequent histologic type, although more than half of canine prostate carcinomas exhibited intratumoral heterogeneity. In many cases, primary tumors showed mixed morphology, characterized by two or more types of differentiation. Duration of testicular hormone exposure was significantly different between dogs with adenocarcinoma and dogs with mixed morphology tumor, but did not appear to influence the frequency or pattern of metastases. Overall, gross metastases were present in 80% of dogs with prostate carcinoma. Skeletal metastases were present in 22% of cases, and the predominantly axial skeletal distribution of these lesions was similar to that reported in men with prostate carcinoma. Young dogs were at highest risk for development of skeletal metastases. CONCLUSIONS This study provides a more complete characterization of spontaneous prostate carcinoma of dogs in terms of morphologic heterogeneity, skeletal metastases, and the influence of testicular hormones. Prostate carcinoma in pet dogs provides an immunocompetent, autochthonous tumor system that mimics certain aspects of human prostate cancer. This spontaneous model may contribute to our understanding of the factors that regulate carcinogenesis within the aged prostate, and to the development of chemoprevention strategies or bone‐targeted therapies. Prostate 45:173–183, 2000. © 2000 Wiley‐Liss, Inc.

Results suggested that fine-needle aspiration may be a sensitive and specific method of evaluating the regional lymph nodes in dogs and cats with solid tumors, because results correlated well with results of histologic examination of the entire lymph node. Physical examination alone was not a reliable method and should not be used to decide whether to aspirate or biopsy the regional lymph nodes.

Findings do not support the hypotheses that specific brands or types of vaccine within antigen class, vaccine practices such as reuse of syringes, concomitant viral infection, history of trauma, or residence either increase or decrease the risk of vaccine-associated sarcoma formation in cats. There was evidence to suggest that certain long-acting injectable medications may also be associated with sarcoma formation.