Synchronous epithelioid stromal tumour and lipoma in the stomach

McMaster University Medical Center, Hamilton, Ontario Correspondence: Dr Jasim Radhi, Department of Pathology, McMaster University Medical Center, 1200 Main Street West, Hamilton, Ontario L8N 3Z5. Telephone 905-525-9140 ext 76313, fax 905-521-6142, e-mail radhi@ hhsc.ca Received for publication March 6, 2003. Accepted March 31, 2003 N Al-Brahim, J Radhi, J Gately. Synchronous epithelioid stromal tumour and lipoma in the stomach. Can J Gastroenterol 2003;17(6):374-375.

G astrointestinal stromal tumours (GISTs) are a heteroge- neous group of mesenchymal tumours; their clinical and histological features vary depending on their location within the gastrointestinal tract.They occur predominantly in older patients and are equally distributed between men and women.Seventy per cent of the tumours occur in the stomach, 20% to 30% in the small intestine and less than 10% in the esophagus, colon and rectum (1).Lipomas are rarely found in the stomach.They are asymptomatic, but may occasionally cause obstruction or bleeding.
It is very unusual for different tumours to coexist in the same organ.In the stomach, GISTs have been found alongside mucosa-associated lymphoid tissue lymphoma (2) and adenocarcinoma (2,3).In the small intestine, the coexistence of a GIST and carcinoid tumour of the ampulla has been reported (4).
The present report describes the synchronous occurrence of a GIST and a submucosal lipoma in the antrum of the stomach.This combination of two mesenchymal gastric tumours has not previously been described in the literature.

CASE PRESENTATION
An 82-year-old man presented with a three-day history of abdominal pain and melena following alcohol ingestion.Previous history included an episode of upper gastrointestinal bleeding with melena in 1988.Endoscopy at that time demonstrated a small polypoid lesion with an apical ulcer.A biopsy of the lesion showed hyperplastic mucosa with ulceration, but no malignancy.The patient was observed for few days and repeat endoscopy showed that the ulcer had healed.
On admission, endoscopy revealed a large polypoid antral lesion with apical ulceration.The lesion was further evaluated by computed tomographic scan that revealed a prepyloric mass arising from the posterior wall, which measured 6 cm in diameter.The patient was treated by distal gastrectomy.

PATHOLOGICAL FINDINGS
The specimen received was a distal gastrectomy with attached portion of greater omentum.Two submucosal nodules were present in the antrum.The first nodule was well-circumscribed and measured 6.5×4.0×3.0 cm.There was a small apical ulcer at the apex.On section, the consistency was rubbery and the cut surface was tan-coloured.The second nodule was also wellcircumscribed and measured 2.5×1.5×1.5 cm.It was of soft consistency and its cut surface was yellow (Figure 1).

DISCUSSION
GISTs are mesenchymal heterogeneous neoplasms that arise throughout the gastrointestinal tract.The presenting symptoms depend on tumour size and site.The most common symptom in patients with gastric GISTs is upper gastrointestinal bleeding.There is recent evidence that the cells in these tumours have many features of interstitial cells of Cajal (5).Predicting the clinical behaviour of these tumours is notoriously difficult.However, a recent study (6) has demonstrated that benign gastric GISTs could be diagnosed by a constellation of histological features other than counting mitosis or measuring tumour size.In addition, there are individual morphological features that are associated with an aggressive clinical course, including tumour size greater than 7 cm, mucosal invasion, cellularity in epithelioid type, high nuclear grade, mitotic count higher than five mitoses per 50 high power field and myxoid changes (6).
Lipomas of the gastrointestinal tract are benign, single and slow growing lesions.They occur most commonly in the colon and small bowel, and very rarely in the stomach.Most are detected incidentally, but they can cause obstruction or bleeding (7).
The synchronous occurrence of epithelial and stromal tumours in the stomach has been reported rarely in the literature.To our knowledge this represents the first case report of two synchronous mesenchymal tumours of the stomach.Coincidence alone could account for such an association.