Page 1346 - Clinical Small Animal Internal Medicine

1284 Section 11 Oncologic Disease

regurgitation. Other symptoms include weight loss, ano- Staging for gastric tumors includes abdominal ultra-
VetBooks.ir rexia, halitosis, pain, and aspiration pneumonia. In some sound, thoracic radiographs (three‐view) and minimum
database. Abdominal radiographs rarely reveal gastric
cases, respiratory signs may be the only symptom. The
paraneoplastic syndrome hypertrophic osteopathy has
mality. Paraneoplastic hypoglycemia can be seen with
been reported secondary to S. lupi‐induced sarcomas. tumors. Anemia is the most common laboratory abnor-
A history of progressive vomiting, often with digested leiomyomas or leiomyosarcomas. Sporadically, ele-
blood “coffee grounds” or tinged with fresh blood, is vated liver enzymes and elevated gastrin levels can be
common in cases of gastric cancer. Weight loss, anorexia, documented.
and cachexia are often noted over a period of weeks to Grossly, there are three variations of gastric carcinoma
months. Paraneoplastic hypoglycemia can be seen sec- that have been identified. Diffuse neoplastic infiltration
ondary to leiomyomas or leiomyosarcomas and is likely of the gastric wall can produce a thickened, nondistensi-
due to the production of insulin‐like growth factors. ble stomach known as “leather bottle stomach.” Gastric
EPCs may be associated with hyperproteinemia, mono- adenocarcinoma may also manifest as a discrete,
clonal gammopathy, and hypercalcemia. On occasion, polypoid lesion or as mucosal plaques with ulceration.
occult blood or melena can be documented in the feces. Histopathologically, gastric adenocarcinomas may be
classified as a diffuse type with randomly arranged,
malignant epithelial cells or an intestinal type with
Diagnosis neoplastic cells that are well organized into distinct,
glandular structures. The clinical significance of these
Staging for tumors of the esophagus should include tho- histopathologic types is not currently known.
racic radiographs (three‐view), minimum database Ultrasonography is a useful imaging modality.
(complete blood count [CBC], serum biochemistry pro- Carcinomas tend to be sessile and occur most commonly
file, and urinalysis) and an abdominal ultrasound to rule on the lesser curvature and gastric antrum. Benign
out a possible primary tumor when the esophageal tumor lesions are pedunculated or well circumscribed and
is suspected to be metastatic. often occur at the cardia. Sometimes, it is easier to find
Thoracic radiographs of the cervical region and thorax gastric lymphadenopathy secondary to metastasis than
may be helpful in localization of esophageal tumors and/ the primary gastric lesion. An ultrasound‐guided fine
or secondary aspiration pneumonia. Esophageal tumors needle aspirate or Tru‐Cut biopsy can be utilized to
appear as a homogeneous mass in the region of the obtain a diagnostic sample.
esophagus, with gas retention and dilation proximal to Gastroscopy with a flexible endoscope is the most
the lesion. Some esophageal tumors may appear calci- sensitive and specific noninvasive way to identify and
fied. Positive contrast esophagrams with barium will localize lesions and obtain biopsies. When obtaining
usually demonstrate the lesion with or without fluoros- biopsies, multiple samples should be taken from multiple
copy. Lesions appear as a rounded or lobulated, smoothly sites because the majority of gastric tumors have signifi-
elevated filling defect. cant necrosis, ulceration and inflammation, making
When available, esophagoscopy is definitive because it histopathologic examination difficult.
can locate the lesion and obtain diagnostic tissue sam- Barium contrast gastrograms can often document
ples for histopathology. Esophageal tumors are typically infiltrative disease of the gastric wall, but these contrast
submucosal over which the mucosa is usually freely mov- studies are cumbersome and take a relatively long time
able. Narrowing of the lumen is common, while stenosis to perform. Poor motility, delayed gastric emptying time
and obstruction are rare. Computed tomography (CT) or and/or prolonged adherence of contrast material to
magnetic resonance imaging (MRI) may be helpful in ulcerated tissue are common findings. It should be noted
determining extent of involvement, location, and inva- that it could take over 24 hours for barium to completely
siveness. Leiomyoma can be presumptively diagnosed leave the stomach, which would delay the ability to per-
based on endoscopic examination and CT results that form gastroscopy.
indicate a well‐defined, round‐to‐ovoid encapsulated Open surgical biopsy is the most definitive method of
mass, with no ulceration of the overlying mucosa or evi- diagnosis. Leiomyoma/leiomyosarcmas should be stained
dence of local invasion. Endoscopic biopsies are con- with CD117 (c‐kit) to differentiate GISTs.
traindicated with leiomyomas, as they increase the risk
of complications and mucosal perforation during sur-
gery. Endoscopic fine needle aspiration is effective for Therapy
obtaining a tentative diagnosis and does not affect surgi-
cal outcome. EPCs have a predilection for the terminal There are limited therapeutic options for esophageal can-
esophagus and cardia. A thoracotomy or cervical explo- cer. Intrathoracic access is challenging and surgery usu-
ration can be performed to obtain a biopsy. ally results in tension on the anastomosis site and