Teaching Case

A 54 year old hypertensive male patient presented with complaints of recurrent vague epigastric pain and discomfort for 11 months. With suspicion of cardiac cause, he was evaluated by cardiologist for no outcome. On upper GI endoscopy, there was a submucosal swelling at the gastric antrum. He underwent CT thereafter.

A large homogeneous smooth hypo-dense submucosal lesion with few internal hyper-dense strands was noted in the gastric pre-pyloric antrum causing narrowing of luminal calibre. The lesion showed no surface irregularity / ulceration. There was no evidence of internal enhancement on IV contrast.
The oral contrast was noted passing over the lesion with no areas of pooling within the lesion.
Mean Hounsfield Unit (HU) value of the lesion was "-102" HU.

A. Background

Gastrointestinal (GI) lipomas are rare benign mesenchymal tumours with a possibility to occur anywhere along the entire gastrointestinal tract (GIT). GI lipomas account for about 1% of the gastric tumours [1]. These can be submucosal, subserosal or intramural in location, with submucosal being the most common location accounting up to 95% [2].

B. Clinical Perspective

Typically, symptoms of gastric lipoma are related to the size and location of the tumour. There are reports of epigastric pain being the usual presentation [1] and others which mention upper GI hemorrhage as the common presentation [3]. Smaller lesions of size <2 cm are usually asymptomatic but increase in size of the lesion and presence of ulceration can cause symptoms.
In our case, the patient had no episodes of bleeding, probably due to the fact that the lesion had no significant ulcerations on the surface at the time of presentation. This becomes an important aspect to be communicated with the physician for a prompt treatment response.

C. Imaging Perspective

Computed tomography (CT) would yield a definitive result in identifying the lipomatous lesion successfully owing to a smooth, well defined hypo-dense lesion with average HU values ranging from '- 70' to '-120' [4]. The mean HU value in our case was '-102'. On CT, lipomas are usually homogeneous, except when there is surface ulceration and surrounding erosion which may manifest as irregular hyper-dense fat stranding at the surface[5]. The fat stranding at the base should also not be mistaken for liposarcomatous transformation [4].

Other conventional diagnostic tools like fluoroscopy would be of less specific significance, unless compressibility of the lesion could be established, which is not possible in every case [6]. In situations contraindicating CT, a Magnetic resonance imaging (MRI) study would establish the smooth lipomatous nature of the lesion. Endoscopic ultrasonography would also help in diagnosis.

Potential complications include GI hemorrhage [1] and GI obstruction directly related to tumour size or by virtue of prolapse into duodenum and subsequent intussusception [4]. Malignant transformation to liposarcoma is extremely rare [6].

D. Outcome

With characteristic findings on CT, biopsy is usually not required [4, 7]. It is recommended only in lesions with equivocal findings and surgery is the mainstay of treatment [4, 8].

E. Teaching points

Gastric lipoma must be a potential differential in all the cases where submucosal mass in found at imaging.

Written informed patient consent for publication has been obtained.