Ulcerated duodenal gastrointestinal stromal tumour presenting as severe anaemia

Clinical History

A 63-year-old Indian woman presented with fatigue and pain in the abdomen. On physical examination she had a palpable mass in the right hypochondrium region. The routine laboratory investigations revealed severe anaemia (haemoglobin 3.3gm).

Imaging Findings

On ultrasound (US), a large mixed echoic mass with internal vascularity could be seen compressing inferior vena cava (IVC) and right kidney with a clear plane with liver (Fig.1). Barium meal follow through was performed which showed widened C loop of duodenum (Fig. 2). Contrast-enhanced Computed Tomography (CECT) was done which showed a well defined heterogeneously enhancing mass lesion arising from medial wall of second part of duodenum compressing IVC and displacing C loop of duodenum laterally (Fig. 3a,b). The mass lesion measured 13 x 10 x 18 cm and showed an area of ulceration on its lateral wall communicating with duodenal lumen. No abdominal lymphadenopathy as detected. Hepatic parenchyma was clear without any focal lesion.

Discussion

Gastrointestinal stromal tumours arise from interstitial cells of Cajal which are regarded as the pacemaker of intestine. They express receptor tyrosine kinase c-kit, also known as CD-117. [1] 40-60% of GISTs occur in the stomach, 30-40% in the small intestine, 10% in the colon and rectum and 5% in oesophagus. [2] Clinical presentation can be with abdominal pain, melena, haematemesis, anaemia or palpable mass. Duodenal tumours can present with features of biliary obstruction. As they grow exophytically, intestinal obstruction is not a frequent finding.
Radiologically, small tumours show uniform contrast enhancement on CECT, where as larger tumour enhances heterogeneously owing to the necrosis and haemorrhage. Internal haemorrhage can give fluid-fluid levels and multiple septations. Instead of lymphadenopathy which is a usual feature of adenocarcinoma, mesenteric metastases and omental mass formation are more common in GIST. Fifty percent of GISTs show mucosal ulceration as they have tendency to invade muscularis propria. [3] Large stromal tumours sometimes show signs of crescent-shaped necrosis containing air or the “Torricelli-Bernoulli” sign. [4] Unlike the previous concept that, less than 2 cm size tumours are generally benign, recent studies showed the risk of recurrence as they express C-KIT mutation. [5] Liver metastatic lesions show homogenous enhancement and complete washout on venous phase; so they can be missed in single phase studies. Necrosis can occur in larger lesions.
Surgery remains the mainstay of treatment and complete resections are generally indicated. For duodenal GISTs, duodenal and pylorus sparing surgery is the first line of management. Post operative treatment with tyrosine kinase inhibitor like imatinib 400mg per day (first choice) or sunitinib 50mg per day for 4 weeks should be given to intermediate and high risk patients. [5, 6] The risk characterization is done based on the criteria proposed by Miettinen et al. [7]
In conclusion CT remains the chief modality to define their origin, aggressiveness, heterogeneity and metastases for diagnosis, management and follow up of GISTs.

Differential Diagnosis List

Final Diagnosis

Histopathology and immunohistochemistry confirmed duodenal stromal tumour.

URL:	https://www.eurorad.org/case/11268
DOI:	10.1594/EURORAD/CASE.11268
ISSN:	1563-4086