CASE 12680 Published on 26.05.2015

Gastric leiomyoma: radiographic, endoscopic and MRI findings

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Tonolini Massimo, MD1; Ippolito Sonia, MD1; Bareggi Emilia, MD2.

"Luigi Sacco" University Hospital,
(1) Department of Radiology
(2) Department of Gastroenterology
Via G.B. Grassi 74, 20157 Milan, Italy;
Email:mtonolini@sirm.org
Patient

40 years, female

Categories
Area of Interest Stomach (incl. Oesophagus) ; Imaging Technique Echocardiography (transoesophageal), MR
Clinical History
An overweight female patient was being considered for possible bariatric surgery. She was asymptomatic apart from episodes of gastric pyrosis, had no significant past medical history. Physical examination and routine laboratory tests did not reveal abnormal findings.
Imaging Findings
Double-contrast upper gastrointestinal study (Fig. 1) revealed a broad-based filling defect in the cardias, forming obtuse angles with the adjacent gastric wall. Endoscopy (Fig. 2) confirmed a 2.5 cm ovoid protruding lesion near the gastroesophageal junction, covered by normal mucosal surface without ulceration: biopsy was deemed unfeasible owing to the location.
Cross-sectional imaging of the mass was performed with tailored MRI of the stomach (Fig. 3), using pharmacological hypotonisation and peroral distension using 800 ml water, which achieved optimal luminal and mural distension. The demarcated submucosal cardial lesion showed intermediate T1 (no out-phase signal drop) and homogeneous low T2 signal intensity, poor and progressive contrast enhancement, without features suggesting gastrointestinal stromal tumour such as necrosis and haemorrhage, transmural or exoenteric growth.
Endoscopic follow-up and repeated MRI (Fig. 4) six months later showed unchanged lesion. Endoscopic ultrasound-guided biopsy (not shown) failed to provide a pathologic diagnosis.
Laparoscopic surgery, including hiatoplasty and Toupet fundoplication, confirmed gastric leiomyoma.
Discussion
An uncommon but not exceptional endoscopic finding, subepithelial gastric masses (SEGMs) are typically mesenchymal in origin, arise within the submucosa or muscularis propria with normal overlying mucosa, and may grow in an endoluminal, exophytic, or mixed fashion. Often incidentally discovered, SEGMs may cause epigastric discomfort, nausea and vomiting, pain or early satiety. Larger lesions may ulcerate and bleed, causing haematemesis, melaena or iron-deficiency anaemia [1].
Unfortunately, endoscopy cannot fully characterize SEGMs. Double-contrast barium studies depict SEGMs as well-circumscribed protruding lesions forming obtuse angles with the adjacent gastric wall, usually with smooth margins and mucosal surface; large size and ulceration suggest malignancy. Among SEGMs, gastric leiomyomas (GLs) represent the commonest benign gastric tumours, consist of well-differentiated bundles of smooth muscle cells in collagen connective matrix, most usually appear as broad-based cardial masses, and do not require surgery unless symptomatic. Differentiation from other mesenchymal proliferations is crucial, particularly from the more common gastrointestinal stromal tumours (GISTs) associated with a variable risk or progression and metastasis [1-3].
Diagnostic workup of SEGMs mostly relies on endoscopic ultrasound (EUS) which depicts GLs as well-demarcated homogeneous hypoechoic lesions arising in the muscularis mucosa and muscularis propria. EUS criteria including high echogenicity, hyperechoic spots, and marginal halo suggest GISTs with 89.1% sensitivity and 85.7% specificity. Since conventional endoscopic biopsies are typically insufficient, EUS-guided biopsy or a modified deep-tissue biopsy technique after preliminary mucosal incision are required to provide adequate submucosal tissue samples for microscopic and immunohistochemical (particularly C-KIT staining) studies [1, 2, 4].
Cross-sectional imaging including luminal distension and pharmacological hypotonisation proves helpful for assessment of SEGMs. To differentiate GLs from GISTs, helpful CT criteria include cardial location, round/ovoid shape, intraluminal growth, small size (<3.35 cm longest, <2.3 cm shorter diameters), homogeneous enhancement, absent necrosis, poor enhancement (<12.5 and <31.5 Hounsfield units in arterial and portal venous phase respectively) [3, 5-7].
Providing non-radiation imaging with excellent tissue contrast, MRI is increasingly used to investigate gastrointestinal tract disorders, despite technical challenges to overcome artefacts from intraluminal gas, peristalsis, cardiac cycle and respiratory motion. Although MRI applications in the stomach are currently limited to motility studies and tumour staging, in this patient (after suspicious EUS and inconclusive biopsy) MRI allowed visualization of the previously unreported appearance of a GL, excluding features suggesting GIST such as T2-hyperintense or heterogeneous neoplastic tissue, avid and persistent contrast enhancement, necrosis and haemorrhage, transmural or exoenteric growth. Therefore, MRI may help further investigate SEGMs and obviate unnecessary surgery [6, 8, 9].
Differential Diagnosis List
Submucosal leiomyoma of the gastric cardias
Gastrointestinal stromal tumour (GIST)
Leiomyosarcoma
Neuroendocrine tumour e.g. gastric carcinoid
Lymphoma
Metastasis
Ectopic pancreas
Schwannoma / Neurofibroma / Glomus tumour
Inflammatory myofibroblastic tumour
Final Diagnosis
Submucosal leiomyoma of the gastric cardias
Case information
URL: https://eurorad.org/case/12680
DOI: 10.1594/EURORAD/CASE.12680
ISSN: 1563-4086