Urinary tract neoplasia

Invasive leiomyosarcoma involving the tongue of an Arabian mare

A 10 year-old endurance Arabian mare was presented with an invasive, firm, multilobulated mass at the left ventral face of the tongue. The mare had a history of four months of ptyalism, dysphagia, severe halitosis, and dysmastication. The Evaluation of the horse included physical and oral examination, complete blood count and serum biochemistry profile, computed tomography evaluation of the head, and histopathology of the mass. The computerized tomography (CT) head scan showed the homogeneous mass in the oral cavity confirming the degree of invasion on the tongue, as well as a small mineral focus at the left dorsal mandibular border and increased density of the submandibular lymph nodes. At necropsy, gross findings in the oral cavity revealed an irregular, nodular and partially ulcerated mass at the level of the body of the tongue in the ventral aspect, with a size of approximately 10 × 15 × 8 cm. Histologically, the tongue revealed a neoplastic process of mesenchymal muscle origin. The tumor cells showed distinctive morphological and architectural patterns in some areas. An immunohistochemistry panel was done yielding a positive reaction for Calponin and Desmin, confirming diagnostics of as a soft tissue leiomyosarcoma in the tongue. Immunohistochemistry results, in combination with histopathologic morphology, were suggestive of a leiomyosarcoma originating in the perivascular wall tissue. Oral leiomyosarcoma are very rare in veterinary medicine, and to the authors' knowledge, this is the first case report to utilize histopathology, immunohistochemistry and imaginology to describe oral leiomyosarcoma in a horse.

Renal neoplasia in horses - a retrospective study

OBJECTIVE

Being confronted with a case series of renal neoplasia in several horses which was in striking divergence to literature data, we recognized the need of a retrospective study to assess the presence of renal neoplasms in horses.

MATERIAL AND METHODS

Anamnestic animal data, necropsy findings and results of histological and immunohistochemical examinations from 2010 through 2015 were collected and evaluated regarding renal neoplasia.

RESULTS

Data from postmortem examinations of 1069 horses revealed 20 horses with renal tumors constituting a prevalence of 1.87 %. Primary renal neoplasms built the majority of cases (n = 15; 75 % of total renal neoplasms) and comprised nine renal carcinomas, four renal adenomas, one renal neuroendocrine tumor and a single nephroblastoma. Among the five secondary renal neoplasms lymphosarcoma was most common (3/5). Remaining metastatic tumors comprised one melanoma and one hemangiosarcoma. No breed or sex predilections were noticeable. Except for the case of nephroblastoma in a stillborn foal, all horses presenting with renal tumors were more than 10 years of age, often older than 20 years. Anamnestic data and clinical symptoms were inconclusive and not assigned to renal disease in most cases. Merely one horse with renal carcinoma presented with renal insufficiency and two horses showed signs of shock due to severe bleeding after tumor capsule rupture in renal carcinoma.

CONCLUSION AND CLINICAL RELEVANCE

Renal tumors occur more often than anticipated, especially in older horses. Contradictorily to the literature, primary renal tumors significantly outnumbered secondary neoplasms in this study.

Neoplasia in 125 donkeys (Equus asinus): literature review and a survey of five veterinary schools in the United States and Canada

A diagnosis of neoplasia was noted in 125 of 357 donkeys (35%) in our review of medical records from 5 veterinary schools in the United States and Canada. Equine sarcoid was the most common tumor in our study, accounting for 72% of all tumors and 82% of cutaneous tumors. Soft-tissue sarcomas were the second most common skin tumors. All other types of neoplasia were rare. Important differences in the occurrence of neoplasia in donkeys compared to horses included the rarity or absence of squamous cell carcinoma in any organ system and gray horse melanoma. Lymphosarcoma, the most common malignant tumor in horses, appears to be very rare in donkeys. We report several tumors in donkeys including melanocytoma, peripheral nerve sheath tumor, and gastrointestinal stromal tumor. Our data demonstrate commonalities as well as differences in neoplastic diseases of donkeys and horses. Understanding differences in carcinogenesis among these 2 closely related species can inform researchers pursuing pathogenic mechanisms of equine disease and inform veterinary diagnosticians regarding tumor prevalence.

Poorly differentiated leiomyosarcoma of the urogenital tract in a horse

CASE DESCRIPTION

A 2-year-old Thoroughbred filly was evaluated because of hemorrhage from the vulva and suspected hematuria of 5 days' duration.

CLINICAL FINDINGS

A primary coagulopathy was ruled out on the basis of results of hematologic testing. Vaginoscopy and cystoscopy revealed a large bleeding mass in the bladder that extended into the vagina, causing marked obliteration of normal urogenital structures and difficulty in urination. Histologic examination of endoscopic and surgical biopsy specimens revealed a poorly differentiated neoplasia likely of mesenchymal origin. Chronic suppurative cystitis caused by Streptococcus zooepidemicus was also diagnosed.

TREATMENT AND OUTCOME

The tumor continued to grow despite treatment with doxorubicin and, within 45 days, was causing substantial discomfort and stranguria. Given the grave prognosis, the horse was euthanized. At necropsy, the tumor was found to have caused widespread destruction of the urinary bladder and to have invaded the broad ligament of the uterus. The mass was identified as a poorly differentiated leiomyosarcoma on the basis of results of histologic examination and immunohistochemical staining for alpha-actin.

CLINICAL RELEVANCE

Findings suggested that leiomyosarcoma should be considered in the differential diagnosis when examining horses with urogenital bleeding.

Renal Mucus Gland Cystadenomas in a Horse

A 35-year-old horse was submitted to the necropsy service at the University of Kentucky Livestock Disease Diagnostic Center. At necropsy, multiple 1–4-cm-diameter cystic structures were incidentally identified unilaterally in the right renal medulla and the cortex. On histologic examination, the cystic structures compressed the normal renal architecture, were lined by tall columnar epithelium that formed occasional papillary projections, and contained large amounts of mucicarmine and periodic acid–Schiff-positive mucinous material. The masses were diagnosed as renal mucus-gland cystadenomas. This tumor should be considered as a differential diagnosis when cystic structures are identified in the equine kidney.

Papillary Renal Adenoma of Distal Nephron Differentiation in a Horse

A 20-year-old thoroughbred mare had a mass in the right kidney. The mass was encapsulated with fibrous capsule and composed of variably-sized papillary projections lined by a single layer of flattened to cuboidal neoplastic epithelial cells with no cytological and nuclear atypia. Immunohistochemically, the neoplastic cells were broadly positive for cytokeratin AE1/AE3 and granular staining for alpha-1-antitrypsin was focally detected; this immunohistochemical property was similar to that of the normal distal nephron. From these results, this case was diagnosed as papillary renal adenoma of distal nephron differentiation.

Transitional cell carcinoma of the urinary bladder in a Thoroughbred, with intra-abdominal dissemination

A 14-year-old Thoroughbred gelding with a history of acute onset of hematuria was presented for necropsy. Transitional cell carcinoma of the urinary bladder with intra-abdominal dissemination was diagnosed. Tumor masses were observed on the splenic capsule and surrounding the distal abdominal aorta. Tumor cells showed diffuse cytoplasmic reactivity for cytokeratin but were negative for epithelial membrane antigen, carcinoembryonic antigen, tumor-associated glycoprotein 72, and vimentin.