Sex: male
Age: 52 years
History
Epigastric pain, nausea and dyspepsia since four months.
Laboratory data
Sideropenic anemia (Hgb 9.8 g/dl, Hct 31%).
Physical findings
Epigastric palpable mass.
Case text
The patient was admitted to the hospital because of digestive bleeding.
Image 1-3
Ultrasound of the upper abdomen.
Axial scans (images 1,2) and longitudinal scan (image 3) of the epigastric region.
Image 4
Barium study of the stomach.
Double contrast study, lateral view.
Image 5-8
CT of the upper abdomen.
Axial enhanced CT scan of the upper abdomen (images 5-8).
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1. What is the abnormality present on the US scan of the epigastric region?
Roughly round mass, 10.5 cm in diameter, partly liquid and partly solid.
2. Which is more likely the origin of the mass?
The mass is separated from spleen and liver, possibly arising from the pancreatic tail or from the stomach.
3. Which is your diagnosis?
Cystic tumor of the pancreas.
4. What is the differential diagnosis?
Cystic tumor of the stomach.
5. What is your next diagnostic step?
Barium study of the stomach.
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6. What is the abnormality present on the barium study of the stomach?
Mass of the posterior wall of the body of the stomach, with smooth surface and sharp mucosal angles.
7. Which is your diagnosis?
Intramural tumor of the stomach. A pancreatic tumor is less likely.
8. What kind of tumor do you consider?
A mesenchymal tumor, either benign (i.e. leiomyoma, neurinoma, fibroma) or malignant (i.e.leiomyosarcoma) or a gastric lymphoma could be suggested. The latter is less likely due to the smooth surface.
9. What is your next diagnostic step?
CT of the abdomen.
Image 5-8
10. What is the abnormality present on the CT scan of the upper abdomen?
Mass, 12 cm in diameter, protruding into the stomach, partly inhomogeneously solid partly liquid.
11. Can you assess the origin of the mass?
The mass originates from the gastric wall. A fatty layer separating the mass from the pancreas is evident.
12. What is your diagnosis?
Cystic tumor of the stomach
13. Can you suggest the benign or malignant nature of the tumor?
The inhomogeneity of the mass and its size favour the malignant nature (i.e. leiomyosarcoma).
14. What is your next step?
Surgery is required.
The patient underwent total gastrectomy. A well marginated white mass with cystic component was found. The histology was consistent with the diagnosis of leiomyoblastoma of the stomach. No findings suggesting malignancy were found. The patient recovered promptly.
Final diagnosis
Leiomyoblastoma of the stomach.
Differential diagnosis
US findings suggest:
1. cystic tumor of the pancreas
2. cystic tumor of the stomach
The barium study suggests a mesenchymal tumor of the stomach. A lymphoma or a pancreatic tumor are less likely.
CT confirms the gastric origin and the inhomogeneous structure of the mass suggesting a leiomyosarcoma.
Discussion
Leiomyoblastomas are rare smooth muscle tumors of the stomach, representing 0.3% of all gastric tumors. They occur mainly in adult males, mainly in the antrum. The most common presenting symptoms are gastrointestinal bleeding, pain, and fatigue or malaise. Malignant potential and prognosis of these tumors are controversial. The large majority of them are benign, but malignancy has been reported to occur in up to 12% of cases. The best determinants of tumor behavior are histologic grade and mitotic count (grade II or more and mitotic count greater than 5/10 HPF favour malignancy).
Other significant prognostic factors include size (larger than 6 cm), aneuploidy and higher S-phase fraction.
Abdominal CT is the most specific diagnostic procedure obtained preoperatively because it shows the gastric origin of the mass and the intramural location and allows to detect possible findings suggesting malignancy.
However differentiation from other intramural tumors, leiomyosarcoma in particular, can be impossible.