Ultrasonographic and clinicopathologic findings in 21 dogs with intestinal adenocarcinoma

Computed tomographic findings may be useful for differentiating small intestinal adenocarcinomas, lymphomas, and spindle cell sarcomas in dogs

An improved understanding of the CT characteristics for histologically confirmed primary intestinal tumors would be helpful for guiding prognosis and treatment plans in affected dogs. This retrospective, multi-center, analytical study aimed to evaluate the CT characteristics for the differentiation of adenocarcinoma, lymphoma, and spindle cell sarcoma (SCS) in dogs. Thirty-seven dogs who underwent contrast CT and histopathological examinations were included (adenocarcinomas, n = 11; lymphomas, n = 12; SCS, n = 14). Quantitative and qualitative CT parameters, including tumor morphology, contrast enhancement pattern, Hounsfield unit (HU) value, and presence or absence of intraabdominal lymphadenopathy, were evaluated for each included small intestine tumor CT case. Adenocarcinomas tended to show endophytic growth, intestinal obstruction, and a heterogeneous enhancement pattern. Lymphomas tended to show exophytic growth, contrast enhancement of the intestinal tumor mucosal layer, a homogeneous enhancement pattern, and the presence of lymphadenopathies in the abdominal cavity. SCSs tended to show lobulated growth, a large cystic portion within the tumor, a heterogeneous enhancement pattern, a large size with fat stranding sign, and lower HU values in postcontrast images. Cut-off values of the minimum diameter/fifth lumbar vertebral mid-body height (≥5.80; area under the curve [AUC] = 0.97, P < 0.001) and minimum HU value/HU value of the aorta (≤0.26; AUC = 0.96, P < 0.001) were derived to discriminate SCS from the two other tumor types. In conclusion, contrast CT characteristics may be useful in differentiating small intestinal adenocarcinomas, lymphomas, and SCSs in dogs.

Ultrasonographic intestinal muscularis thickening in dogs with histologically confirmed inflammatory bowel disease: 13 cases (2010-2021)

Ultrasonographic intestinal muscularis thickening has not been described as an imaging feature of canine inflammatory bowel disease. In this retrospective case series, patients were identified by searching sonographic reports for "muscularis" and/or "muscular layer." Patients were included if small intestinal muscularis thickening was reported, and sonographic images and histopathological samples of the small intestine were available for review. Cases with small intestines nodules, masses, or complete loss of wall layering were excluded. Sonographic images were retrospectively evaluated for jejunal muscularis layer thickness, and ratios of intestinal layer measurements were performed. Histological samples were retrospectively reviewed. Thirteen dogs met inclusion criteria: all dogs had sonographic intestinal muscularis thickening relative to the submucosa (>1.0, range of 1.3-2.5), and most dogs had muscular layer thickness above normal published ranges (11/13; all 13/13 above the weight-specific mean). More than half of the patients had overall normal wall thickness (11/13) and several had normal mucosal echogenicity (6/13). Therefore, in some dogs, the only sonographic abnormality in the small intestine was muscularis thickening. No dogs had lymphadenomegaly. Endoscopic partial-thickness (n = 11, duodenum and/or ileum) or surgical full-thickness (n = 2) samples confirmed inflammatory bowel disease. Direct comparison between jejunum sonographic characteristics and histology features was limited due to both partial thickness biopsies and lack of direct comparison between anatomical locations of ultrasonographic assessment and biopsy site. However, no cases that met the inclusion criteria had normal small intestinal histology. Comparable to cats, dogs with ultrasonographic intestinal muscularis thickening may have inflammatory bowel disease, and further workup for enteropathy is indicated.

CT features of gastrointestinal spindle cell, epithelial, and round cell tumors in 41 dogs

There is sparse published information on computed tomographic (CT) characteristics of canine gastrointestinal tumors. The purposes of this multi-center, retrospective, descriptive study were to describe the CT features of histologically-confirmed canine gastrointestinal spindle cell, epithelial, and round cell tumors and, when available, describe the corresponding ultrasound findings. The inclusion criteria were as follows: availability of pre-and post-contrast CT study, and a histopathological diagnosis of the lesions. Recorded parameters were tumor size, location, gastrointestinal wall layers involvement, lesion's growth and enhancement patterns, tumor margination, presence of stenosis, mineralization, ulcerations, lymphadenopathy, or other lesions in the abdomen/thorax. When available, ultrasound images were evaluated. Forty-one dogs met the inclusion criteria and had the following histological diagnoses: 21/41 (51%) spindle cells (7 leiomyomas, 14 leiomyosarcomas/gastrointestinal stromal tumors (GISTs)), 13/41 (32%) epithelial (adenocarcinoma), and 7/41 (17%) round cell (lymphoma) tumors. The growth pattern was concentric, eccentric, and mixed in epithelial, spindle cell, and round cell tumors, respectively. Spindle cell tumors had the largest main volume and involved the outer gastrointestinal layer with an unaffected inner layer. Leiomyosarcomas/GISTs showed irregular margins compared to leiomyomas. Only lymphomas showed multifocal gastrointestinal involvement. Nine carcinomas and six spindle cell tumors caused partial stenosis with secondary sub-obstruction. Mineralizations were more frequent in spindle cell tumors (10/21) and absent in lymphomas. Lymphadenomegaly was widespread in lymphomas, regional in leiomyosarcomas-GISTs and adenocarcinomas, and absent in leiomyomas. The reported CT features may be useful in prioritizing the differential diagnosis between spindle cell, epithelial, and round cell tumors, similar to those reported on ultrasound.

Clinical and Pathological Diagnosis of Hereditary Gastrointestinal Polyposis in Jack Russell Terriers

Simple Summary

In dogs, hundreds of hereditary diseases are currently known, representing a major health problem in small animal clinical practice. Hereditary gastrointestinal (GI) polyposis in Jack Russell Terriers (JRTs) is a hereditary disease recently discovered in Japan. This is an autosomal dominant disease caused by a germline variant in the adenomatous polyposis coli (APC) gene. Dogs with hereditary GI polyposis develop solitary and multiple tumors predominantly in the stomach and/or colorectum but have a much better prognosis than sporadic cases of GI tumors. Since the discovery of this disease, the number of newly diagnosed cases in Japan has increased, allowing the update of the disease’s clinical and pathological features. In the present study, some patients exhibited more severe condition than previously reported, including cases harboring tumors in the small intestine besides the stomach and colorectum. In addition, the rare cases died from systemic metastasis of GI tumors. Our study would facilitate the accurate diagnosis of hereditary GI polyposis in JRTs and raise global awareness of this novel hereditary disease.

Abstract

Hereditary GI polyposis in JRTs is a novel hereditary disease characterized by the development of solitary and multiple polypoid tumors, predominantly in the stomach and/or colorectum. Our recent study indicated that JRTs with GI neoplastic polyps harbor an identical germline variant in the APC gene, c.[462_463delinsTT], in a heterozygous state. Unlike sporadic cases, dogs afflicted with hereditary GI polyposis can be expected to have a prolonged survival time, as hereditary tumors are noninvasive. Since the discovery of this disease, the number of newly diagnosed cases in Japan has increased, allowing us to update the clinical and pathological features and provide a large number of diagnostic images. The present clinical case series study employing various diagnostic imaging techniques revealed that some of the cases harbored tumors in the small intestine in addition to the stomach and colorectum. Moreover, although rare, hereditary GI cancers can progress to the advanced stage and develop systemic metastasis, similar to sporadic GI tumors. These findings indicate that there is a wider range of variation in disease severity than was initially recognized. Our results can contribute to the accurate diagnosis of hereditary GI polyposis in clinical practice, pathological examinations, and future research.

Familial adenomatous polyposis in dogs: hereditary gastrointestinal polyposis in Jack Russell Terriers with germline APC mutations

Many hereditary disorders in dogs have equivalents in humans and thus attract attention as natural animal models. Breed predisposition to certain diseases often provides promising clues to explore novel hereditary disorders in dogs. Recently, cases of gastrointestinal (GI) polyps in Jack Russell Terriers (JRTs) have increased in Japan. In 21 affected JRTs, polyps were found in either or both the stomach and colorectum, with a predilection for the gastric antrum and rectum. Multiple polyps were found in 13 of 21 examined dogs, including 5 dogs with both gastric and colorectal polyps. Some dogs were found to have GI polyps at an early age, with the youngest case being 2.3 years old. Histopathologically, 43 of 46 GI polyps (93.5%) were diagnosed as adenomas or adenocarcinomas. Immunohistochemical analysis revealed cytoplasmic and nuclear accumulation of β-catenin in the tumor cells. As in the case of human patients with familial adenomatous polyposis, all examined JRTs with GI polyps (n = 21) harbored the identical heterozygous germline APC mutations, represented by a 2-bp substitution (c.[462A>T; 463A>T]). The latter substitution was a non-sense mutation (p.K155X) resulting in a truncated APC protein, thus suggesting a strong association with this cancer-prone disorder. Somatic mutation and loss of the wild-type APC allele were detected in the GI tumors of JRTs, suggesting that biallelic APC inactivation was involved in tumor development. This study demonstrated that despite differences in the disease conditions between human and dog diseases, germline APC mutation confers a predisposition to GI neoplastic polyps in both dogs and humans.

[Intrapelvic leiomyoma causing concurrent colonic and urethral obstruction in a dog]

An 8-year-old female spayed dog was presented due to simultaneous inability to defecate and urinate. During digital rectal examination a smooth, rounded, firm-elastic mass was detected. Laboratory results showed a 6-fold elevation of serum lactate dehydrogenase activity. Ultrasonographic, radiographic and computed tomography findings raised the suspicion of a leiomyoma. An ultrasound-guided fine needle aspiration biopsy was performed under mild sedation but cytologic evaluation was inconclusive. During laparotomy the mass was located at the colorectal transition. It was completely removed while keeping the intestinal wall intact. The results of the histopathological examination and immunohistochemistry confirmed the initial tentative diagnosis of a leiomyoma. Postoperatively the patient was able to pass urine and feces spontaneously. Six months later the dog presented clinically unremarkable. Abdominal ultrasound and rectal examination exhibited no signs of recurrence. Lactate dehydrogenase activity was only marginally increased.

The Site of Origin of Canine Abdominal Masses Correlates with the Risk of Malignancy: Retrospective Study of 123 Cases

Simple Summary

The detection of abdominal masses in dogs is a common finding in clinical practice. While data regarding masses in specific abdominal organs are available in the literature, studies comparing the site distribution of benign versus malignant lesions are scarce. The aim of this study was to retrospectively describe the tissue distribution and diagnosis of surgically excised abdominal masses in a canine population. A total of 123 abdominal masses were classified based on the organ of origin and histologically classified as non-neoplastic (39), benign neoplasia (15), and malignant neoplasia (69). Gastrointestinal masses were more likely to be malignant than masses in other sites. The masses not associated with any organ were significantly larger than the genital and splenic lesions, and no association between size and malignancy was found. This case series suggests that, while the size of the lesion cannot be used as a parameter to predict the probability of a mass being malignant neoplasm, the gastrointestinal site may be used for this scope, providing useful information for primary care clinicians.

Abstract

The detection of an abdominal mass represents a common finding in clinical practice. The aim of this study was to retrospectively describe the tissue distribution and diagnosis of abdominal masses amenable to surgical removal in a canine population. Dogs with abdominal masses with a minimum diameter of 3 cm were selected. Cases were classified, based on the anatomical location, as splenic, gastrointestinal, hepatobiliary, genital, and masses not associated with any organ. Masses were surgically removed and formalin-fixed for the histological examination. Collected data were statistically analyzed. A total of 123 masses were collected from 122 dogs. Sixty-nine masses were classified as malignant neoplasia, 15 as benign, and 39 as non-neoplastic. The abdominal masses were 5.8-fold more likely to be malignant if located in the gastrointestinal tract (p = 0.01). A significant association between the size and the site of the masses was identified, the masses not associated with any organ being larger than the genital and splenic lesions (p = 0.008). This case series describes the most frequent location in association with the histopathological diagnosis of canine abdominal masses and suggests that the gastrointestinal location was related to a higher risk of representing a malignant neoplasm.

Primary Adenosquamous Cell Carcinoma of the Ileum in a Dog

A 9-year-old male, castrated Chihuahua was examined because of a 7-day history of intermittent vomiting. A mass in the small intestine was identified on abdominal radiography and ultrasonography. Laparotomy revealed a mass lesion originating in the ileum, and surgical resection was performed. The mass was histologically diagnosed as adenosquamous cell carcinoma. Chemotherapy with carboplatin was initiated, but the dog was suspected to have experienced recurrence 13 months after surgery and died 3 months later. To our knowledge, this is the first case report to describe the clinical course of adenosquamous cell carcinoma in the small intestine of a dog.

Retrospective study of survival time and prognostic factors for dogs with small intestinal adenocarcinoma treated by tumor excision with or without adjuvant chemotherapy

OBJECTIVE To estimate survival time for dogs with small intestinal adenocarcinoma (SIACA) following tumor excision with or without adjuvant chemotherapy and to identify factors associated with survival time. DESIGN Retrospective case series with a nested cohort study. ANIMALS 29 client-owned dogs with surgically resected, histologically diagnosed SIACA. PROCEDURES Medical records were reviewed and data collected regarding dog signalment; clinical signs; physical examination findings; PCV; serum total solids concentration; diagnostic imaging results; tumor size, location, and histologic characteristics (serosal extension, lymphatic invasion, surgical margins, and lymph node metastasis); type of adjuvant chemotherapy; NSAID administration; and survival time. Variables were assessed for associations with survival time and hazard rate via Kaplan-Meier and Cox proportional hazards analyses. RESULTS Overall median survival time for dogs with SIACA following tumor excision was 544 days (95% confidence interval, 369 to 719 days). Based on Kaplan-Meier estimates, the 1- and 2-year survival rates were 60% and 36%, respectively. On multivariate analysis, only age category was an independent predictor of survival over the follow-up period. Dogs < 8 years of age had a significantly longer median survival time (1,193 days) than dogs ≥ 8 years (488 days). Lymph node metastasis, adjuvant chemotherapy, NSAID administration, and other assessed variables were not associated with survival time. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that SIACA in dogs carries a fair prognosis following excision, even when lymph node metastasis is present. Prospective studies are warranted to better characterize the effects of adjuvant chemotherapy or NSAID administration on survival time.

Ultrasonographic features of colonic B-cell lymphoma with mesenteric lymphomatosis in a cat

A 10-year-old male neutered Domestic Shorthair cat was referred for chronic inappetence, weight loss, and hematochezia and an abdominal mass. Abdominal ultrasonography revealed a heterogeneously hypoechoic transmural colonic mass, which extended beyond the serosa and into the adjacent mesentery. Cytology and clonality assays of fine needle aspirates of the mass and mesenteric nodules yielded a diagnosis of B-cell lymphoma. Colonic lymphoma with mesenteric involvement can have a similar appearance to carcinomatosis, therefore a definitive diagnosis requires sampling and further testing of the mesenteric lesions.

Tubulopapillary rectal adenocarcinoma in dog: clinical, surgical, pathological and immunophenotypical aspects: case report

ABSTRACT Intestinal carcinomas are rare in dogs. The prognosis and survival time are dependent of the histological type, the invasion of the intestinal wall by the malignant cells and the ability of primary neoplasm to produce metastasis. This study reports a case of a Yorkshire dog that developed a rectal tubulopapillary adenocarcinoma progressing to a peritoneal carcinomatosis and multiple metastasis in large intestines, bladder, kidney, iliac lymph node, liver and lungs, six months after transanal surgical resection of the primary rectal neoplasm. Clinical, surgical, pathological and immunophenotypic findings are described. COX-2 imunohistochemical score was higher in hepatic metastasis (score 9) than in the primary tumour (score 6), and the growth fraction (Ki-67) observed was of 49.2% in the rectal neoplasm.

Focal intestinal lipogranulomatous lymphangitis in 10 dogs

OBJECTIVES

To describe the clinical and pathological features of canine focal lipogranulomatous lymphangitis, to evaluate its underlying infectious cause and to compare it with human Crohn's disease.

METHODS

Retrospective review of case records with a histopathological diagnosis of focal lipogranulomatous lymphangitis. Bacterial and fungal colonisation was evaluated using fluorescence in situ hybridisation and histochemical staining, respectively. A comparison with Crohn's disease was performed by a human pathologist.

RESULTS

Ten dogs were evaluated. The historical complaints were predominantly chronic diarrhoea (10/10) and vomiting (5/10). The biochemical abnormalities included hypoalbuminaemia (6/10) and hypocobalaminaemia (4/6). Abdominal sonography revealed a thickened distal ileum±ileocolic junction. Colonoscopy showed a swollen caecal ostium and oedematous caecum in 7/10 dogs. A stenotic ileo-colic opening prevented endoscopic intubation in all dogs. Histology from the resected lesions revealed granulomatous inflammation involving the muscularis and serosa. Fluorescence in situ hybridization demonstrated invasive bacteria in 2/10 dogs. Post-resection, all dogs received metronidazole and tapering immunosuppressive doses of prednisolone. Remission (median 17 months) was achieved in 8/10 dogs.

CLINICAL SIGNIFICANCE

Focal lipogranulomatous lymphangitis is a rare and severe form of canine inflammatory bowel disease with preferential localisation to the ileum and the ileocolic junction. An underlying infectious aetiology was not identified.

PREVALENCE AND SIGNIFICANCE OF AN ULTRASONOGRAPHIC COLONIC MUSCULARIS HYPERECHOIC BAND PARALLELING THE SEROSAL LAYER IN DOGS

The muscularis layer of the canine colon has been reported to appear homogeneously hypoechoic on ultrasonography. A hyperechoic band in the muscularis layer paralleling the serosal surface has been observed by authors in routine canine abdominal ultrasound examinations. The purpose of this prospective and retrospective cross-sectional study was to determine the prevalence of this lesion, characterize its ultrasonographic and postmortem histologic features, and correlate its presence with clinical signs of gastrointestinal disease. In the prospective study, all dogs that underwent routine abdominal ultrasonography by one of two observers during a 4-week period were included without any exclusion criteria. One observer reviewed ultrasound images and recorded the presence or absence of this lesion and its distribution, e.g. focal (< 2 cm long) or diffuse (> 2 cm long). In the retrospective study, all dogs that had both abdominal ultrasonography and necropsy from January 2011 to December 2013 were included without any exclusion criteria. Histologic examinations were performed by two observers and Masson's trichrome stain was used to identify fibrous collagen. Prevalence for the hyperechoic band was 32% in the prospective and 4.8% in the retrospective sample populations, respectively. The hyperechoic band appeared as diffuse, focal, or a combination of both. Histologic sections were available for six dogs. In a few cases, the lesion corresponded to the presence of fibrous tissue in the myenteric plexus or in the tunica muscularis. None of the dogs had a history of diarrhea. Findings supported the hypothesis that a colonic muscularis hyperechoic band paralleling the serosal layer in dogs could be a normal variant rather than a marker of disease.

An Overview of Small Animal Veterinary Sonography

This article is an overview of the field of small animal veterinary sonography, including its history, examples of utilization, and a brief review of the small animal abdominal sonographic examination that includes images of normal examples and typical pathology.

Focal intestinal lipogranulomatous lymphangitis in 6 dogs (2008-2011)

Background

Lipogranulomatous lymphangitis is inflammation of the intestinal lymphatic vessels and surrounding tissues caused by chronic leakage of lipid‐laden chyle. Grossly, lipogranulomas are typically disseminated small masses on the serosa and surrounding lymphatic vessels and consist of epithelioid macrophages, multinucleated giant cells, and cholesterol. Lipogranulomatous lymphangitis is occasionally seen in patients with lymphangiectasia and protein‐losing enteropathy (PLE).

Objectives

To characterize the historical features, clinical signs, treatment, histopathology, and outcome of dogs with focal lipogranulomatous lymphangitis.

Animals

Six dogs with ultrasonographic evidence of focal, regional small intestinal masses, often with involvement of the adjacent mesentery, and a diagnosis of focal lipogranulomatous lymphangitis based on histopathology of biopsied masses.

Results

The median age of dogs was 6.9 years (range 3–10 years). All dogs had total protein, globulin, and albumin concentrations within the reference range at initial presentation and had intestinal masses identified on abdominal ultrasound examination. Histopathologic evaluation of lesions identified severe mural and mesenteric lipogranulomatous lymphangitis. Lymphangiectasia was noted in 5 cases and only in sections within the mass‐like lesion; tissue without lipogranulomas had minimal lymphangiectasia, suggesting a localized phenomenon. Postoperative outcomes ranged from remission of clinical signs with no subsequent treatment for 10–12 months in 2 dogs, postoperative management with medical and nutritional management in 3 dogs, and no outcome for 1 case.

Conclusions and Clinical Importance

This case series describes a unique mass‐like manifestation of intestinal lipogranulomatous lymphangitis and should be considered as a possible differential diagnosis in dogs with an intestinal mass.

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.

Emesis in dogs: a review

Emesis is a common presenting sign in small animal practice. It requires a rational approach to management that is based upon a sound understanding of pathophysiology combined with logical decision making. This review, which assesses the weight of available evidence, outlines the physiology of the vomiting reflex, causes of emesis, the consequences of emesis and the approach to clinical management of the vomiting dog. The applicability of diagnostic testing modalities and the merit of traditional approaches to management, such as dietary changes, are discussed. The role and usefulness of both traditional and novel anti-emetic drugs is examined, including in specific circumstances such as following cytotoxic drug treatment. The review also examines areas in which common clinical practice is not necessarily supported by objective evidence and, as such, highlights questions worthy of further clinical research.

Surgical Excision of Primary Canine Rectal Tumors by an Anal Approach in Twenty-Three Dogs

OBJECTIVE

To describe an anal approach for excision of primary rectal tumors in dogs and to report outcome.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n=23) with primary rectal tumors.

METHODS

Review of medical records (1990-2000) of dogs with primary rectal neoplasia excised surgically using an anal approach with rectal prolapse. With dogs anesthetized, the rectum was prolapsed, stabilized with stay sutures during tumor excision with 1 cm margins to the level of the muscularis, then the rectal mucosa was sutured.

RESULTS

Each dog had only 1 tumor type (adenocarcinoma [8], solitary polyp [5], carcinoma [4], plasmacytoma [2], adenoma [1], leiomyoma [1], mucinous carcinoma [1], and papilloma [1]). Mean tumor volume was 3.1 cm(3) (range 0.1-37.7 cm(3)). Postoperative complications (rectal bleeding [5], tenesmus [4]) were mild and resolved within 7 days after surgery; another dog had partial mucosal dehiscence identified at 6 days. The primary tumor was incompletely excised in 1 dog (4.3%), and local recurrence occurred 16 and 24 months after surgery in 2 dogs. Outcome beyond the immediate postoperative period was known for 18 dogs, including 2 dogs still alive. Mean postoperative disease-free interval for these 18 dogs was 36.8 months (range 5-84 months).

CONCLUSION

Surgical excision of tumors of the caudal rectum can be accomplished through the anus after rectal prolapse.

CLINICAL RELEVANCE

An anal approach facilitated by rectal prolapse should be considered as a viable option for the surgical treatment of selected cases of tumors of the caudal aspect of the rectum in dogs.

Diagnostic value of ultrasonography in differentiating enteritis from intestinal neoplasia in dogs

One hundred and fifty dogs with histopathologically confirmed intestinal disease were evaluated retrospectively. Sixty-one dogs had enteritis and 89 dogs had intestinal neoplasia. Ultrasonographic findings including the thickness and distribution of the intestinal lesion, the integrity of intestinal wall layering, regional lymph node thickness, the location of the intestinal segment involved, and regional motility were evaluated. Dogs with intestinal tumor had wall thickness (1.5 cm) significantly greater than dogs with NSE lesions (0.6 cm; p < 0.001). Ninety-nine percent of dogs with intestinal tumor had loss of wall layering while 88% of dogs with NSE had normal or altered wall layering (p < 0.001). Dogs with NSE were significantly more likely to have diffuse lesion (72%) than dogs with intestinal tumor (2%; p < 0.001). Lymph node median thickness in 24/61 dogs with NSE was 1.00 cm. The median thickness of the lymph nodes in 56/89 dogs with intestinal tumors was 1.9 cm. A multivariate analysis showed that loss of wall layering alone was an excellent predictive factor in differentiating intestinal tumor from NSE. In our population, dogs with loss of intestinal wall layering were 50.9 times more likely to have a tumor than enteritis.