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579.e4 Leiomyoma, Leiomyosarcoma

Advanced or Confirmatory Testing for postoperative GILMS patients. Exact Technician Tips
• GI contrast radiography (e.g., barium series), frequency is based on clinical signs and A large-gauge (20-gauge) needle may improve
VetBooks.ir • The gold standard for diagnosis is biopsy with PROGNOSIS & OUTCOME mass. An aspiration technique tends to be more
endoscopy, or CT may confirm gastroesopha-
cellular return when aspirating a mesenchymal
tumor location.
geal or intestinal obstruction and/or mass.
productive than a core technique.
histopathologic evaluation, preferably surgi-
cally rather than endoscopically to resect the Prognosis depends on tumor location: Client Education
entire neoplasm if possible. Histopathologic • Dogs with hepatic leiomyosarcoma fre- If leiomyosarcoma, monitor for signs indicat-
grade may be prognostic. quently develop metastases and have a grave ing recurrence or abdominal metastasis (e.g.,
• Immunohistochemical staining is required prognosis. vomiting, diarrhea, abdominal distention, and
to differentiate leiomyosarcomas from GIST. • Dogs with gastric or intestinal leiomyosar- abdominal pain).
comas may have metastatic rates > 54%,
TREATMENT but many can have a good prognosis, even SUGGESTED READING
with confirmed metastasis (e.g., median Cohen M, et al: Gastrointestinal leiomyosarcoma
Treatment Overview survival of 21.7 months for those surviving in 14 dogs. J Vet Intern Med 17:107-110, 2004.
Treatment requires stabilizing the patient and the perioperative period, including dogs with
attempting wide and complete surgical resection metastatic disease); 1-year survival rate of ADDITIONAL SUGGESTED
of the entire tumor (if possible). 75%, 2-year survival rate of 66%, and 3-year READINGS
survival rate of 60%.
Acute General Treatment • Dogs with cecal leiomyosarcomas may have Grooters A, et al: Canine gastric leiomyoma.
Compend Contin Educ Vet 17:1485, 1995.
Stabilization of systemic effects: hypoglycemia, a lower metastatic rate (10%) and better Kapatkin AS, et al: Leiomyosarcoma in dogs: 44 cases
anemia (e.g., due to GI hemorrhage), electrolyte overall prognosis. Most dogs with successful (1983-1988). J Am Vet Med Assoc 201:1077, 1992.
and acid-base disturbances (e.g., due to chronic resection of a cecal tumor eventually die of Mass CP, et al: Reclassification of small intestinal and
vomiting) causes unrelated to the tumor. cecal smooth muscle tumors in 72 dogs: clinical,
• Colorectal leiomyomas: mean survival of histologic, and immunohistochemical evaluation.
Chronic Treatment 31.6 months Vet Surg 36:302, 2007.
• Complete surgical resection McPherron M, et al: Colorectal leiomyomas in seven
dogs. J Am Anim Hosp Assoc 28:43, 1992.
○ May be curative, depending on the grade PEARLS & CONSIDERATIONS Russell KN, et al: Clinical and immunohistochemical
and absence of metastasis differentiation of gastrointestinal stromal tumors
○ If small-intestinal, removal of 5 cm of Comments from leiomyosarcomas in dogs: 42 cases (1990-
normal bowel on either side of the tumor • Leiomyosarcomas most commonly occur in 2003). J Am Vet Med Assoc 230:1329, 2007.
and wide resection of the corresponding the cecum and jejunum. They are the second Selting KA. Intestinal tumors. In Withrow SJ, et al,
mesentery are recommended. most common intestinal tumor in dogs. editors: Withrow and MacEwen’s Small animal clini-
○ Even with gross metastatic disease, surgical • Even with metastatic disease, including cal oncology, ed 5, Philadelphia, 2013, Saunders,
resection of leiomyosarcomas can afford gross hepatic and mesenteric involvement pp 412-423.
long-term survival. apparent at laparotomy, GILMS is associated Withrow SJ: Gastric cancer. In Withrow SJ, et al,
○ Mesenteric lymph nodes, liver, and with a fair life expectancy (mean, 2 years) editors: Withrow and MacEwen’s Small animal clini-
cal oncology, ed 5, Philadelphia, 2013, Saunders,
suspected metastatic lesions should be postoperatively. pp 402-405.
biopsied for staging purposes. • Some GILMSs have been reclassified as
• Dogs with metastasis or a high likelihood GISTs by immunohistochemical techniques RELATED CLIENT EDUCATION
of metastasis (based on tumor location; (GISTs express KIT and are CD-117 positive;
see Prognosis & Outcome below) can be true GILMSs do not). GISTs are derived SHEETS
considered candidates for chemotherapy, from interstitial cells of Cajal, the pacemaker Consent to Perform Abdominal Ultrasound
although no studies have shown efficacy of cells of the GI tract (regulate motility and Consent to Perform Endoscopy, Upper GI (or
chemotherapy against these tumors. peristalsis). One study indicated that in dogs, Gastroduodenoscopy)
GILMSs and GISTs might behave differently
Possible Complications (GILMSs more commonly located in the Consent to Perform Exploratory Laparotomy
• Varies, depending on the types of treatments stomach and small intestine; GISTs more Consent to Perform Fine-Needle Aspiration
of Masses
and the location of the primary tumor commonly located in the cecum and large
• A 50% rate of localized peritonitis associated intestine). GISTs also might be more locally AUTHOR: M. Raquel Brown, DVM, DACVIM
with tumor rupture has been reported. invasive and more likely to cause periopera- EDITOR: Rance K. Sellon, DVM, PhD, DACVIM
tive death as a result of GI wall perforation
Recommended Monitoring and sepsis. Another study found no clinical
• According to clinical signs importance of reclassification but noted that
• Exam and three-view thoracic radiographs future treatments may be dictated by this
and abdominal ultrasound q 3 months division.

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