General Considerations
- LSA is the most common gastric tumor in cats (solitary or multicentric) and most are FeLV negative
- Sex predisposition: males
- Gross appearance: discrete mass or diffuse gastric wall diffusion
+ Clinical Signs
- Clinical signs are caused by gastric outflow obstruction, altered motility, or chronic blood loss secondary to tumor necrosis and ulceration
- Progressive vomiting is common and may contain fresh or digested blood
- Weight loss may be caused by poor digestion, protein malnutrition, or cancer cachex
+ Laboratory Tests
- Laboratory tests and survey radiographs are usually unrewarding
- Leiomyoma and leiomyosarcoma have been associated with paraneoplastic hypoglycemia
- Microcytic hypochromic anemia is common with chronic blood loss and occult blood may be detected in feces
- Increased liver enzymes may be seen with hepatic metastasis or obstruction of the common bile duct
Imaging
+ Radiographs
Positive- or double-contrast radiographs: gastric tumors can appear as a mass effect, ulcer crater, delayed gastric emptying with poor motility, and delayed adherence of contrast material to an ulcerated tumor
+ Ultrasonography
- Ultrasonographic findings include transmural thickening of the gastric wall with loss or altered layering (poor echogenic outer and inner lining with hyperechoic central zone)
- Other findings include tumor location, ulceration, extension through gastric wall, and lymphadenopathy
- Gastric ADC tend to appear as sessile mass located in the lesser curvature or antrum
+ Endoscopy
- Gastroscopy allows direct visualization and guided biopsy
- Several biopsies should be performed as superficial ulceration, necrosis, and inflammation is common
- Submucosal masses are difficult to biopsy and false-negative results are common
+ Other Imaging Techniques
- CT
- MRI
TREATMENT
+ Surgery
- Surgery is possibly solitary feline gastric LSA but complicated by advanced stage at presentation, frequent metastasis, difficult access, and debilitated animal
- Lymph node metastasis is variable and all abdominal lymph node should be evaluated for staging purposes
- Curative resection should be attempted if disease is localized to the stomach
- Surgical techniques: Billroth I or II or palliative bypass procedures
- Billroth I or II provides immediate relief of gastric outflow obstruction and clinical improvement in early postoperative period
- Billroth II (partial gastrectomy and gastrojejunostomy) or complete gastrectomy (with biliary by-pass) are very extensive surgeries with high morbidity and minimal survival advantage
- Partial gastrectomy preferred in humans due to better nutritional status and quality of life and radical gastrectomy does not improve survival time
- Palliative gastrojejunostomy for inoperable or metastatic lesions but associated with significant morbidity including anastomotic ulcers
+ Chemotherapy
Gastric LSA does not respond well to conventional chemotherapy protocols and chemotherapy may not be required following surgical resection of solitary gastric LSA in cats
+ Prognosis
- Prognosis depends on surgical excision, tumor type and grade, and presence of metastatic lesions
- Gastric LSA: MST 40 weeks with Madison-Wisconsin protocol and 15.5 months with prednisolone-chlorambucil