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.

[A gastrointestinal stromal tumour of the caecum in a pony with colic]. / Gastrointestinaler stromaler Tumor im Zäkum bei einem Pony mit Kolik.

A 25-year-old pony mare was presented to the clinic with preliminarily reported severe acute colic. The pony during the previous week had shown inappetence, apathy and fever of unknown origin. Clinical examination and placement of a gastric tube were indicative of a secondary gastric dilation. Rectal exploration found moderate caecal meteorism with a tensed and painful medial taenia as well as a dilated and fluid-filled small intestine. In addition, a solid, mobile, non-painful structure of approximately 10 cm diameter was palpated ventrally. A hyperechogenic mass close to the caecum was detected using ultrasonography of the abdomen in the right flank. The peritoneal fluid was an exudate with cytological signs of an acute to subacute peritonitis. Blood analysis showed markedly increased plasma lactate concentration and a marginal neutrophilia and lymphopenia, with a total leukocyte count of 6 G/l. Because the owners refused consent for a laparotomy and the pony showed increased signs of severe pain despite conservative medical treatment, it was euthanized. The main findings on necropsy were extensive adherence of the caecal apex to the right and left colon and the ileum as well as a neoplasia in the lumen of the caecal apex. The mass, which was covered with a mucous membrane, had a tough consistency. The cut surface was grey-white to beige-coloured and multilobular with numerous necrotic and acute haemorrhagic areas. According to histopathological and immunohistochemical findings, the mass was characterized as a gastrointestinal stromal tumour (GIST), a rare neoplasia in horses.

Cecal vascular hamartoma causing recurrent colic in an Arabian mare.

A 5-year-old mare was treated for recurrent colic and weight loss by surgical removal of an intraluminal cecal mass. Microscopic examination revealed vascular hamartoma. A 6-month follow-up showed an improvement in the general condition of the mare. Vascular hamartoma should be one of the differential diagnoses for weight loss and colic.

Coliques récurrentes causées par un hamartome vasculaire caecal chez une jument Arabe. Une jument de 5 ans a été traitée pour coliques récurrentes et perte de poids par exérèse chirurgicale d'une masse caecale intraluminale. L'examen microscopique a révélé un hamartome vasculaire. Un suivi de 6 mois a montré une amélioration de l'état général de la jument. L'hamartome vasculaire doit faire partie du diagnostic différentiel de l'amaigrissement et des coliques.(Traduit par les auteurs).

Nodular typhlitis associated with the nematodes Heterakis gallinarum and Heterakis isolonche in pheasants: frequency and pathology with evidence of neoplasia.

An investigation related to the frequency and pathology of Heterakis gallinarum and pathology of Heterakis isolonche in pheasants from Rio de Janeiro, Brazil was conducted by means of clinical examinations, necropsies, and histopathological analysis in 50 ring-necked pheasants from backyard flocks of 11 localities; also, histological sections of caeca of golden pheasants deposited in the Helminthological Collection of the Oswaldo Cruz Institute (CHIOC) have been considered in the present study. During necropsies, only specimens of H. gallinarum were recovered with a prevalence of 90%, mean intensity of 81.9 and range of infection of 1-413. Gross lesions were characterized by congestion, thickening, petechial haemorrhages of the mucosa, intussusception, and nodules in the cecal wall. Under microscopy, chronic diffuse typhlitis, haemosiderosis, granulomas with necrotic center in the submucosa and leiomyomas in the submucosa, muscular and serosa associated with immature H. gallinarum worms were observed. The examination of histological sections previously deposited in the CHIOC, revealed more severe alterations associated with concomitant infections with H. gallinarum and H. isolonche in golden pheasants, and were characterized by several necrotic areas with cholesterol clefts in the submucosa, giant cell granulomas in the submucosa, and serosa centralized by necrosis and worm sections and neoplastic nodules in the muscular and submucosa.

Secondary erythrocytosis associated with high plasma erythropoietin concentrations in a dog with cecal leiomyosarcoma.

A 14-year-old mixed-breed dog was examined because of severe absolute erythrocytosis (PCV, 70%). Plasma erythropoietin (EPO) concentration was consistently high, even though results of arterial blood gas analyses were normal. Radiography, ultrasonography, urinalysis, and serum biochemical analyses did not reveal any cardiac, pulmonary, or renal abnormalities that could cause the erythrocytosis, and erythrocytosis secondary to inappropriate EPO secretion was diagnosed. The PCV was maintained at approximately 60% by means of periodic phlebotomy, and the dog died of acute renal failure 2 years later. At necropsy, a cecal leiomyosarcoma was identified. Immunohistochemical staining of sections of the tumor revealed intracellular vacuoles containing EPO, and EPO mRNA was detected in the tumor by use of a reverse transcriptase-polymerase chain reaction assay These results suggested that ectopic production of EPO by a cecal leiomyosarcoma was the cause of erythrocytosis in this dog.

Gastrointestinal stromal tumors of the equine cecum.

Ten cecal tumors were identified during the postmortem examination of seven horse carcasses at slaughter (one horse had three tumors). The multinodular and hemorrhagic tumors ranged from 1 to 10 cm in diameter and consisted of spindle cells arranged in thin, interconnected trabeculae that were often separated by sinuses filled with mucinous fluid, erythrocytes, and siderophages. Spindle cells of all tumors were immunopositive for vimentin, neuron-specific enolase, and c-kit protein but lacked reactivity with antibodies to glial fibrillary acidic protein, S100 protein, and desmin. In one tumor, spindle cells diffusely bound antibodies to synaptophysin. Most tumors contained focal reactivity to smooth muscle actin antibodies; one tumor reacted diffusely. Ultrastructurally, tumor cells were connected by desmosome-like structures and exhibited extended cell processes; some contained dense core neurosecretory granules. These equine stromal tumors appeared to share some characteristics with human gastrointestinal stromal tumors.

Neurological signs in a horse due to metastases of an intestinal adenocarcinoma.

A 22-year-old Dutch Warmblood mare was referred to Utrecht University with progressive left hind limb paresis and hyporeflexia. The preliminary clinical diagnosis was the neurological form of equine herpes virus (EHV-1) infection. Within 1 day of admission, the mare became recumbent and deteriorated rapidly. Postmortem examination revealed an adenocarcinoma of the caecum, with metastases in all regional lymph nodes and extending from the lumbar nodes into the vertebral canal, causing spinal cord compression and destruction of the left 4th and 5th lumbar nerves.

Caecal disease in equids.

OBJECTIVE: To review the breed, age, gender, clinical and laboratory findings, treatment and outcome of horses with caecal disease presented to a referral centre. DESIGN: Retrospective study of 96 cases. PROCEDURE: The breed, age, and gender of the study population were compared with the corresponding hospital population for the same period. The means (+/- SD) for clinical and laboratory findings were recorded for each caecal disorder. Treatment was categorised as medical or surgical, and outcome was recorded. RESULTS: Caecal diseases included impaction (40% of total cases), rupture associated with concurrent unrelated disease (13%), rupture with parturition (9%), rupture with no associated disease (5%), infarction (11%), torsion (9%), abscess or adhesion (7%), tumour (3%), and miscellaneous conditions (3%). The breed or gender of affected horses did not differ from the hospital population, although horses > 15 years were more frequently represented (P < 0.05). This age group was specifically more predisposed to caecal impaction (P < 0.05), as were Arabian, Morgan, and Appaloosa breeds (P < 0.05). In horses with caecal impaction transrectal examination was the most useful diagnostic procedure; 90% of affected horses treated medically were discharged while horses treated by typhlotomy alone, or typhlotomy and blind end ileocolostomy, had survival rates to discharge of 71% and 86%, respectively. Horses with caecal rupture associated with concurrent un-related disease showed no signs of impending rupture; all were receiving phenylbutazone, all were euthanased, and 50% had caecal ulceration at necropsy. Of horses with caecal rupture with parturition 56% had prior dystocia; in two-thirds the site of rupture was the ileocaecal junction and all were euthanased. Horses with caecal rupture with no associated disease died or were euthanased; rupture was idiopathic. Horses with caecal infarction usually had signs of abdominal pain and abdominal fluid changes consistent with peritonitis; transrectal examination was nonspecific, and typhlectomy was successful in seven of eight horses. Horses with caecal torsion had signs of severe, acute abdominal pain and typhlectomy was successful in three of five horses. Diagnosis of caecal adhesion or abscess was assisted by transrectal palpation in two of seven horses and surgical treatment was successful in two of five horses. A caecal tumour was diagnosed in three horses aged 20 years or older that presented with chronic weight loss. Other caecal diseases were uncommon. CONCLUSION: Caecal disease is uncommon in equids but some specific features of the history and physical findings can alert the veterinarian to the possibility of caecal involvement in horses with gastrointestinal dysfunction. Medical or surgical therapy can be effective in horses where caecal rupture has not occurred.

Equine adenocarcinomas of the large intestine with osseous metaplasia.

Large intestinal adenocarcinoma with osseous metaplasia was diagnosed in two horses, a 15-year-old standard bred gelding and a 9-year-old Haflinger mare. Clinically, both animals had displayed weight loss and anaemia. A presumptive diagnosis of abdominal neoplasia was made and the horses were humanely killed. At necropsy, the gelding and the mare were found to have ulcerated tumours growing into the lumen of the caecum and colon, respectively. In the mare, the mass extended through the mesocolon and was evident in the left dorsal and ventral colon. Histopathologically, the tumours consisted of well-differentiated cords of single-layered columnar to cuboidal epithelial cells. Mitotic figures were very uncommon. In both lesions, well-formed bony spicules and osteoid were present in the fibrovascular stroma. The tumours were well-demarcated from surrounding mucosal tissue but had invaded the intestinal wall. Metastases were not observed.

Leiomyosarcoma in dogs: 44 cases (1983-1988).

During a 5-year period, leiomyosarcoma was diagnosed in 57 dogs. Forty-four dogs were included in the study on the basis of completeness of medical records. All dogs underwent exploratory laparotomy, and dogs were allotted to 4 groups according to primary site of tumor: spleen (16 dogs, median age 10.3 years), stomach/small intestine (13 dogs, median age 10.3 years), cecum (10 dogs, median age 11.8 years), and liver (5 dogs, median age 9 years). All dogs with leiomyosarcoma of the liver had visible metastasis and were euthanatized at surgery. In the other 3 groups, 79% of the dogs had no gross evidence of metastasis at surgery, and 64% survived greater than 2 weeks. Median survival in these 3 groups was 10 months (range, 1 month to 7 years); 48% died of metastasis, 32% died of unrelated causes, and 16% died of unknown causes. The prognosis in dogs with leiomyosarcoma of the spleen, stomach, small intestine, and especially the cecum is good to excellent if surgery is performed. In dogs with leiomyosarcoma of the liver, the prognosis is poor.

Intestinal myxosarcoma in a thoroughbred mare.

A large fibrotic mass originating from the cecal base was discovered upon surgical exploration of the abdomen in a Thoroughbred mare with a history of chronic colic and weight loss. The mass protruded intraluminally resulting in partial obstruction. Surgical excision was not feasible due to the location of the mass and the inability to exteriorize it adequately from the abdominal cavity. The mass was fibrous with a shiny, gelatinous material present throughout the neoplasm. Histologically, large confluent spaces filled with mucopolysaccharides were identified by staining with Alcian blue. The diagnosis of myxosarcoma was based upon finding of atypical fibroblastic cells, mucinous stroma, local invasiveness, and metastasis to the regional lymph nodes. Myxomatous tumors have not previously been documented to occur in the equine intestinal tract.

Morphology and immunoperoxidase studies of intestinal adenomatosis in the blue fox, Alopex lagopus.

In a blue fox farm about 300 of 400 weanling pups were affected with diarrhoea and prolapse of the rectum. About 40 pups died in an emaciated state after a few days of disease. Eight pups were submitted for examination. Pathological findings were restricted to the caecum, proximal colon and rectum, with occasional extension to the ileum. Affected areas revealed a thick and rigid intestinal wall, a narrow lumen and a thickened, wrinkled and sometimes ulcerated mucosa. Histologically, the mucosa showed long tortuous crypts outlined by a high pseudostratified epithelium which lacked goblet cells. Epithelial cells revealed increased basophilia, and mitoses were seen along the entire crypt length and in the surface epithelium. Silver impregnation showed curved organisms in the apical cytoplasm of the altered epithelial cells. Penetration of the muscularis mucosa by the altered epithelial cells was frequent. The avidin-biotin-immunoperoxidase complex (ABC) technique revealed positive organisms in the apical cytoplasm of altered epithelial cells, when rabbit antisera against different biotypes and serotypes of Campylobacter jejuni and Campylobacter coli were used. Antisera against Campylobacter sputorum subsp. muscosalis and Campylobacter hyointestinalis were negative.