Synchronous Meckel’s diverticulum and Gastro Intestinal Stromal Tumour presenting as acute bleeding.

Clinical History

Meckel’s diverticulum is a congenital abnormality of the gastrointestinal tract seen in 0.3-4% of the population. Bleeding is the most frequent complication, whereas synchronous tumours are rare. The current work reports an incidentally found gastrointestinal stromal tumour in a Meckel’s diverticulum in a 34-year-old male presenting with acute bleeding.

Imaging Findings

A 34 year old Caucasian male presented at our emergency department with severe abdominal pain of increased intensity and melena. Esophagogastroduodenoscopy (EGDS) showed hemorrhagic gastritis, whereas ultrasonography demonstrated a hyperechoed mass of 5x5 cm in diameter located at the left iliac fossa, apparently separated from the urinary bladder. Multi-detector CT angiography (MDCTA) confirmed the presence of a round, well demarcated, non-homogeneous mass adjacent to the urinary bladder and to the small bowel, from which seems to arise. There was no haematoma and/or active bleeding or lymphadenomegaly. There were no CT signs of invasion with regard to the surrounding adipose tissue and the urinary bladder (Fig.1). Conventional angiography demonstrated that the mass is supplied by an afferent arterial vessel arising from the superior mesenteric artery (Fig.1), and drained by a large efferent vein (Fig.2).On laparotomy, the tumour aroused from an ileal diverticulum located at 50 cm from the ileocecal valve. Macroscopically (Fig.4), the diagnosis was as follows: soft tissue tumour arising from a Meckel’s diverticulum.
The histological sample (Fig.5) demonstrated that the mass aroused from the wall of the adjacent pouch of small bowel, and was covered by intact mucosae. It exhibits sheets of neoplastic cells of round to oval appearance with uniform nuclei and indistinct nucleoli, containing a mild vascular network. The cells present eosynophilic fibrillar cytoplasm and indistinct cell borders. The neoplastic cells had the following immunohistochemical phenotype: CD 117 diffusely positive, smooth muscle actin positive, desmin negative, and CD 34 positive.

Discussion

Meckel’s diverticulum (MD), a remnant of the omphalomesenteric duct, is present in 0.3-4% of the population, with equal incidence in males and females [1]. This structure normally regresses between the 5th-7th weeks of foetal life. If this process of regression fails, various anomalies can occur. Among these, MD is the most common abnormality. It is located on the antimesenteric border of the ileum 45-60 cm proximal to the ileocecal valve. Commonly, it is 3-5 cm long, and possesses all the three layers of the intestinal wall [2]. Usually, blood supply comes from the superior mesenteric artery, which makes it vulnerable to infections and obstructions. Since cell lining of vitelline duct are pluripotent, the diverticulum may have ileal mucosa or heterotopic mucosa: gastric (33-52%), pancreatic (5%) and, less commonly (2%), colonic mucosa [2].
So far, several studies on MD have been reported [3-5], none of these studies have focused mainly on the presence of a tumour into a MD. To our knowledge, only a few cases have been published with regard to its presentation as acute bleeding in the emergency setting. Synchronous MD and tumours were reported in only 0.5-3.2% of symptomatic patients. They may be benign or malignant. The overall malignancy rate of tumours in MD is 77%. Analysis of the occurrence of mesenchymal tumours revealed sarcomas in 34% of cases, and benign mesenchymal tumours in 19% of cases [6]. CD 117 is a marker, expression of c-kit gene, a proto-oncogene codifying for a 145-kDa-glucoprotein with 5 III-type-dominium transmembrane with tirosin kinase activity and stem cell factor receptor (Fig.5)
MDCTA is of valuable use in the presumptive diagnosis of synchronous MD and GIST in the emergency setting[6].It is often able to demonstrate a large, and exophytic mass with areas of necrosis (Fig.1). In addition, concomitant findings such as bowel obstruction, abdominal haemorrhage and/or active bleeding can be detected. On the other hand, CT is of limited use in the diagnosis of MD alone because intestinal loops may obscure its presence [6].
Conventional angiography plays a crucial role in the detection and characterization of MD. In addition, it is usually indicated when active bleeding of the GI tract is suspected. Bleeding at the rate of at least 0.5 ml/min is generally necessary in adults to demonstrate contrast material extravasation (a greater rate may be necessary in children)[7]. The angiographic diagnosis is based on the visualization of an anomalous artery supplying the diverticulum, the presence of dense capillary structure, and extravasation of contrast material in actively bleeding patients. Commonly, the principal artery is an ileal branch of the superior mesenteric artery (persistence of the right vitelline artery) [8-10].
Synchronous MD and GIST is a rare condition. Although the diagnosis is obtained histologically, when CT demonstrates a pelvic mass closely associated to the small bowel loops with signs of inflammation and/or haemorrhage, the presence of a synchronous MD and GIST should be suspected.

Differential Diagnosis List

Final Diagnosis

Acute bleeding from a synchronous Meckel's diverticulum and GIST

URL:	https://eurorad.org/case/7477
DOI:	10.1594/EURORAD/CASE.7477
ISSN:	1563-4086