[Intramural jejunal lipoma in the small intestine of a young Arabian horse causing invagination of the jejunum]. / Intramurales Lipom im Jejunum als Ursache für eine Invagination bei einer jungen Araberstute.

A 2-year-old Arabian horse was presented with severe colic symptoms. During explorative laparotomy, a jejuno-jejunal invagination secondary to a submucosal intestinal mass was detected. The involved jejunal segment was surgically removed and an end-to-end anastomosis was created. Opening the specimen demonstrated the presence of a nodular mass on the head of the intussusceptum, measuring 10 cm in diameter, and almost completely obliterating the intestinal lumen. Additionally, a severe hyperemia of the jejunal mucosa was visible. Histological examination, which revealed a well-demarcated mass in the submucosa of the jejunum consisting of well-differentiated adipocytes, led to the diagnosis of an intramural lipoma. The small intestinal mucosa displayed mild to moderate signs of congestion. Pedunculated lipomas in the mesentery of horses causing intestinal volvulus and obstruction are a frequent cause of small-intestine strangulation in aged horses. To the authors' knowledge, intramural intestinal lipomas to date have not been described in the horse. The mare recovered without complications and was free of colic symptoms after 6 months.

ULTRASONOGRAPHIC FEATURES OF CANINE GASTROINTESTINAL STROMAL TUMORS COMPARED TO OTHER GASTROINTESTINAL SPINDLE CELL TUMORS.

Canine gastrointestinal stromal tumors (GISTs) are a recent subtype of gastrointestinal spindle cell tumor recognized with the increasing use of immunohistochemistry. To our knowledge, no imaging features have been described in immunostochemically confirmed canine GISTs. The objective of this retrospective, cross-sectional study was to describe ultrasonographic features of canine GISTs compared with other spindle cell tumors. Thirty-seven dogs with an ultrasonographically visible gastrointestinal mass and a histopathologic diagnosis of spindle cell neoplasia were examined. Immunohistochemistry staining was performed for retrieved tissue samples to further differentiate the tumor type and each sample was interpreted by a single veterinary pathologist. Ultrasonographic features recorded examined included mass echogenicity, homogeneity, presence of cavitation, layer of origin, bowel wall symmetry, and loss of wall layering, location, size, vascularity, and evidence of perforation or ulceration. Tumor types included 19 GISTs, eight leiomyosarcomas, six leiomyomas, and four nonspecified sarcomas. Gastrointestinal stromal tumors were significantly more likely to be associated (P < 0.03) with abdominal effusion than other tumor types. There was overlap between the anatomical locations of all tumors types with the exception of the cecum where all eight tumors identified were GISTs. Besides location, there were no unique ultrasound features of GISTs that would allow distinction from other gastrointestinal spindle cell tumors. Similar to previous studies, GISTs appeared to be the most common spindle cell tumor associated with the cecum in our sample of dogs. The high frequency of abdominal effusion with GIST's was of unknown etiology could possibly have been due to septic peritonitis.

Imaging diagnosis--ultrasonographic appearance of small bowel metastasis from canine mammary carcinoma.

A 10-year-old entire female Beagle dog was evaluated for an acute history of lethargy, anorexia, and diarrhea. Mammary tumors were detected during physical examination. Ultrasonographic scanning revealed the presence of a unique pattern of multiple, well-defined and well-marginated hypoechoic nodules in the muscularis layer of the jejunum. These nodules were not associated with changes in the rest of the normal intestinal layering and were not causing signs of intestinal obstruction. Mammary carcinoma metastases to the intestinal muscularis layer were diagnosed based on histopathological examination.

Diagnosis and treatment of diffuse large B-cell lymphoma in an orangutan (Pongo pygmaeus).

Lymphoma is a common malignancy observed in companion animals. This type of naturally occurring neoplasia has been uncommonly reported in great apes. Diffuse large B-cell lymphoma was diagnosed in an 8-yr-old captive orangutan (Pongo pygmaeus) with gastrointestinal disease by histologic and immunohistochemical methodologies. The orangutan was treated with three cycles of combination chemotherapy (intravenous Rituxan, cyclophosphamide, doxorubicin, and vincristine). The primate has been in good health and exhibiting normal behaviors for more than 15 mo following treatment.

Mesenteric vascular thrombosis associated with disseminated abdominal visceral hemangiosarcoma in a cat.

An adult castrated male cat was evaluated because of a 4 day history of lethargy and partial anorexia. Physical examination revealed abdominal pain with a palpable fluid wave. Cytologic and biochemical analyses of peritoneal effusion were suggestive of septic peritonitis. On surgical exploration of the abdomen, the mesenteric vessels had no palpable pulses and they contained gross thromboses. The intestines were white with no visible peristalsis. Necropsy findings included disseminated, poorly differentiated hemangiosarcoma throughout the abdomen. Mesenteric arterioles contained fibrin thrombi. To the author's knowledge, no previous reports exist of complete mesenteric vascular thrombosis associated with disseminated abdominal visceral hemangiosarcoma in a cat.

Anterior uveitis as an atypical presentation of large granular lymphoma in a caracal (Caracal caracal).

An 11-year-old, female, spayed caracal (Caracal caracal) presented with a 3-month history of intermittent anorexia, vomiting, and weight loss. At examination, bilateral anterior uveitis with anisocoria was present. Further examination under general anesthesia revealed the anterior chamber of the right eye contained copious amounts of thick fibrin, hypopyon, and hyphema obscuring the ventral pupil margin and ventral iris. Aqueous paracentesis revealed a cytologic diagnosis of large granular lymphoma. Additional antemortem diagnostics (computed tomography, ultrasound with fine needle aspiration, and cytology) confirmed the diagnosis of multicentric large granular lymphoma with associated intestinal perforation. Necropsy and histopathology confirmed multicentric large granular lymphoma in the right eye, jejunum, mesenteric lymph nodes, and right kidney. Large granular lymphoma in nondomestic felids is likely rare since it has not been previously reported, but should be considered as a differential in any felid species with anterior uveitis or when lymphoma is considered. In the case of this caracal, the use of aqueous paracentesis with cytology was a powerful diagnostic.

Mesojejunoileac liposarcoma with intrahepatic metastasis in a dog.

We report a liposarcoma at the mesojejunoileum that was widely excised, and then the intrahepatic metastatic liposarcoma was found. The dog was treated by two single-agent chemotherapy separately. The patient was an 8-year-old, male Dachshund, and was referred to our hospital owing to the significant distention of the left abdomen. Neither radiography nor ultrasonography detected the actual association of the tumor with the abdominal viscera before surgery. A large-sized tumor mass that adhered to the mesojejunoileum was explored by laparatomy. Final diagnosis of a pleomorphic liposarcoma was made by the routine histology and further identified by Oil Red O stain. The two single-agent chemotherapy including doxorubicin followed by capecitabine, however, failed to cause remission of the intrahepatic metastatic lesions. The patient died 22 months after operation and the cause of death was supposed to be metastatic liposarcoma.

Expression of brain-derived neurotrophic factor and tropomyosin-related kinase-B in a bovine jejunal nodular ganglioneuroblastoma.

This report describes the morphologic, ultrastructural, and immunophenotypic features of a nodular ganglioneuroblastoma in the jejunum of a 13-month-old Holstein-Friesian heifer. On histologic examination, the mass was composed of clusters of neuroblasts and isolated ganglionic neurons in abundant neurophilic matrix that was surrounded by scanty Schwannian stroma. On ultrastructure examination, the large ganglionic neuron-like cells had unmyelinated neurites. Most ganglionic neuron-like tumor cells expressed neurofilament, neuron-specific enolase, chromogranin A, and S-100, whereas the Schwann-cell-like stromal cells expressed S-100 and vimentin. Both brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase-B (Trk-B) were expressed in ganglionic neuron-like tumor cells, which suggested the activation or reactivation of an embryonic autocrine BDNF/Trk-B pathway that could have prolonged cell survival and promoted differentiation with neurite formation.

T-cell lymphoma with eosinophilic infiltration involving the intestinal tract in 11 dogs.

Among the intestinal tumors of hematopoietic cell origin, lymphoma is the most common in the dog. Herein, we characterized the clinical and pathologic features of 11 dogs (average age, 10.6 +/- 2.5 years) with T-cell lymphoma of the intestinal tract with eosinophil infiltrates. No sex predominance was apparent. All had localized tumor masses in the small intestine. Grossly, the intestinal wall was thickened, and the lumen of the affected intestine was usually narrowed. Microscopically, we observed transmural diffuse invasion of round to pleomorphic tumor cells. Tumor cells showed varying morphology, from scanty to abundant cytoplasm, and round to ovoid nuclei with scattered to dense chromatin. In seven of the dogs, tumor cells had infiltrated into the epithelium. All showed infiltration of eosinophils and all 11 tumors had a T-cell phenotype (CD3+, CD79-). Only one tumor stained positive for the mast cell marker c-kit and none was positive for mast cell tryptase. We did not observe ultrastructurally apparent granules in any of the tumor cells. These results suggest that, in dogs, T-cell lymphomas of intestinal origin resemble mast cell tumors of intestinal origin with respect to cell structure and eosinophil infiltration. Therefore, in the absence of epitheliotropism, it is difficult to confirm the differential diagnosis without immunostaining for mast cell and lymphocyte markers, including mast cell tryptase, c-kit, CD3, and CD79.

Ovine intestinal adenocarcinomas: histologic and phenotypic comparison with human colon cancer.

Approximately 7% of old, unthrifty sheep (Ovis aries) in New Zealand have intestinal adenocarcinomas. To investigate whether these sheep might be used as a model of human colonic neoplasia, the biologic behavior and histologic appearance of ovine intestinal adenocarcinomas were compared with those reported for human colonic adenocarcinomas. We collected 50 intestinal tracts with grossly visible intestinal neoplasia from slaughtered sheep. Neoplasms were assessed using World Health Organization guidelines for assessment of human colonic adenocarcinomas. All ovine adenocarcinomas developed in the small intestine. In contrast, only 4% of human intestinal tumors develop at this location, whereas the majority develop in the colon. A visible polyp is present within 89% of human colonic adenocarcinomas, whereas polyps were present in only 46% of the ovine neoplasms. Intestinal wall infiltration by the neoplastic cells and rates of lymph node (84% in sheep; 61% in humans) and distant (52% in sheep; 17% in humans) metastases were comparable between ovine and human adenocarcinomas. However, ovine adenocarcinomas developed more peritoneal and fewer hepatic metastases than human adenocarcinomas. Histologic grading of ovine tumors revealed cell differentiation similar to that reported within human colonic adenocarcinomas. In conclusion, ovine intestinal adenocarcinomas, like human colonic adenocarcinomas, typically arise spontaneously and consistently develop widespread metastases. In addition, tumors appear histologically similar between these species. Therefore, sheep may provide a model of advanced human colonic cancer, possibly allowing evaluation of novel therapeutics and surgical procedures.

Isolation of Cokeromyces recurvatus, initially misidentified as Coccidioides immitis, from peritoneal fluid in a cat with jejunal perforation.

Cokeromyces recurvatus, a zygomycete, was isolated by fungal culture from the peritoneal fluid of a cat with jejunal perforation secondary to intestinal lymphosarcoma. This organism has not been recovered previously from a veterinary patient. The tissue form of C. recurvatus is morphologically similar to those of Coccidioides immitis and Paracoccidioides brasiliensis and may be misdiagnosed as 1 of these organisms on the basis of cytologic or histopathologic specimens, particularly in geographic regions where these organisms are not endemic.

Alimentary lymphosarcoma in a 4-year-old Labrador retriever.

Lymphosarcoma, a common canine hematopoietic neoplasm, occurs in multicentric, alimentary, mediastinal, and extranodal forms. Alimentary lymphoma accounts for approximately 5% of cases and is less easily diagnosed than the more common multicentric form. Chemotherapy is often effective, but recent therapeutic advances hold great promise for success in treating canine lymphoma. A 4-year-old, black Labrador retriever was presented (day 1) with a 2-day history of vomiting, polyuria/polydipsia, lethargy, and anorexia. The heart and respiratory rates were within normal limits, and the rectal temperature was 38.9 degrees C. Abdominal splinting was noted on palpation, which elicited urination. No obvious additional abnormalities were detected.

Visceral mast cell tumor in a captive black jaguar (Panthera onca).

Little is known about neoplasia in the jaguar (Panthera onca), the largest American feline. A captive black jaguar was diagnosed at necropsy with a mastocytic form of visceral mast cell tumor similar to that which occurs in domestic cats. This animal had no previous clinical disease and died during anesthesia for a routine dental treatment.

Clinicopathological evidence of pseudomyxoma peritonei in a dog with intestinal mucinous adenocarcinoma.

An 11-year-old, intact female Pekingese dog was presented because of chronic vomiting. Clinical examination and diagnostic imaging suggested the presence of an intestinal mass. Laparotomy was performed, and a gelatinous effusion associated with a suspected jejunal neoplasm was found. Accumulation of gelatinous material was grossly evident in several abdominal organs and parietal peritoneum. Cytopathological smears from this material showed macrophages, reactive mesothelial cells, and spindle cells embedded in a mucinous basophilic background. After spontaneous death, necropsy and histopathology were performed and showed the presence of an invasive mucinous adenocarcinoma with visceral and peritoneal metastases. The clinicopathological findings of this case report closely resemble those reported in human cases of pseudomyxoma peritonei.