Gastrointestinal stromal tumours (GISTs) with a thousand faces: atypical manifestations and causes of misdiagnosis on imaging

Gastrointestinal stromal tumors: a comprehensive radiological review

Gastrointestinal stromal tumors (GISTs) originating from the interstitial cells of Cajal in the muscularis propria are the most common mesenchymal tumor of the gastrointestinal tract. Multiple modalities, including computed tomography (CT), magnetic resonance imaging (MRI), fluorodeoxyglucose positron emission tomography, ultrasonography, digital subtraction angiography, and endoscopy, have been performed to evaluate GISTs. CT is most frequently used for diagnosis, staging, surveillance, and response monitoring during molecularly targeted therapy in clinical practice. The diagnosis of GISTs is sometimes challenging because of the diverse imaging findings, such as anatomical location (esophagus, stomach, duodenum, small bowel, colorectum, appendix, and peritoneum), growth pattern, and enhancement pattern as well as the presence of necrosis, calcification, ulceration, early venous return, and metastasis. Imaging findings of GISTs treated with antineoplastic agents are quite different from those of other neoplasms (e.g. adenocarcinomas) because only subtle changes in size are seen even in responsive lesions. Furthermore, the recurrence pattern of GISTs is different from that of other neoplasms. This review discusses the advantages and disadvantages of each imaging modality, describes imaging findings obtained before and after treatment, presents a few cases of complicated GISTs, and discusses recent investigations performed using CT and MRI to predict histological risk grade, gene mutations, and patient outcomes.

Spontaneous Hemoperitoneum From a Ruptured Gastrointestinal Stromal Tumor

This is a case report of a ruptured gastrointestinal stromal tumor (GIST) presenting as spontaneous hemoperitoneum. The patient was a 63-year-old female with a past medical history of hypertension and ulcerative colitis who presented to the emergency department with worsening epigastric pain. The patient denied history of trauma, previous surgeries, or forceful vomiting. She was not on anticoagulation. Vital signs at presentation were stable. A CT scan of abdomen/pelvis revealed a large amount of fluid in the upper abdomen with high attenuation material adjacent to the greater curvature of the stomach concerning for hemoperitoneum. Diagnostic laparoscopy revealed a significant amount of blood along the upper abdominal viscera. The procedure was converted to an upper midline laparotomy after identifying a necrotic, extremely friable 7 x 6 x 3 cm pedunculated mass with active hemorrhage on the posterior aspect of the greater curvature. A wedge resection was performed to remove the mass with grossly negative margins. An intraoperative frozen section revealed a stromal tumor with spindle cells. Final pathology revealed a pT3N0M0 stromal tumor with histologic spindle cells and a high mitotic rate (24/5 mm²) consistent with a high-grade GIST. Given tumor rupture at presentation, the patient was started on imatinib therapy for a minimum duration of three years. GISTs are often asymptomatic or cause mild abdominal pain or GI bleeding. Rarely, an exophytic GIST may rupture leading to intraperitoneal bleeding. Surgical resection with negative margins is the mainstay of treatment although patients presenting with tumor rupture are at higher risk of dissemination and recurrence.

Tumors of the jejunum and ileum: a pattern-based imaging approach on CT

Since a broad spectrum of tumors can occur in the small bowels, it is not easy to make a correct differential diagnosis among small bowel tumors on CT findings. Therefore, once a mass is detected on CT, the radiologist needs to analyze the mass based on presenting patterns such as location, multiplicity, morphology, and enhancement patterns. In this article, we will illustrate various kinds of small bowel tumors based on imaging patterns at CT to facilitate making a correct diagnosis.

Laparoscopic treatment of a large pedunculated hemangioma of the liver: a case report

Hepatic hemangiomas are the most common benign tumors of the liver, often asymptomatic and discovered incidentally. A 62-year-old woman was referred to our Institution under the suspicion of having an 8 cm-sized GIST. Due to the atypical features of the lesion on TC scan, a biopsy was performed. We report the case of pedunculated hepatic hemangioma with the aim to discuss the diagnostic approach, the possible causes of misdiagnosis and the opportunity of the laparoscopic approach.