Presentation and Management of Metastatic Gastrointestinal Stromal Tumors – A Case Series and Review of Literature

Andrea Zelisko, MD, Anselm Tintinu, MD, Andrew Fenton, MD, FACS, Walter Chlysta, MD, FACS. Akron General Medical Center

Gastrointestinal stromal tumors (GISTs) are the most common nonepithelial benign neoplasms of the gastrointestinal (GI) tract and the incidence of GISTs has been increasing with recent studies reporting an incidence rate of ~12 per million. The clinical presentation of GISTs is highly variable depending on a multitude of characteristic features. We report on three patients with atypical clinical presentations with unusual features of GIST and highlight their treatment course.

Case 1: 30-year-old healthy female presented three days after a vaginal delivery with abdominal pain and distension. She was found to have acute blood loss anemia (hemoglobin of 5.7g/dL) but had no reports of GI bleeding. A CT scan revealed a large heterogenous, necrotic mass in her left abdomen and lesions in her liver. She was treated with surgical resection and medical therapy with imatinib as an outpatient.

Case 2: 89-year-old male presented to the emergency department with a complete GI obstruction. A mass was found on CT scan and he was taken to surgery for treatment and removal of the mass. Surgery revealed metastatic disease, lymph node involvement, and small bowel primary. The patient was referred to oncology for medical treatment.

Case 3: 64-year-old male presented with increasing abdominal pain and distension. CT scan was obtained that showed a mass in the abdominopelvic area. Repeat imaging for worsening clinical status demonstrated an increasing amount of free air and fluid. The patient was taken to surgery for excision of the mass, primary anastomosis, and diverting ileostomy. He was treated medically with imatinib and had no signs of recurrent disease.

Tumor Characteristics
Size TNM Type Metastasis Positive Markers Negative Markers
1 17x11x16cm pT4pNXpM1 mixed spindle-epithelioid Liver cKIT, DOG-1, vimentin actin, S100, cytokeratin, EMA
2 15x10cm pT4pN1pM1 spindle LN, omentum, mesentery cKIT-11, CD117, DOG-1 muscle specific acin, calretinin, D862
3 15×14.5×10.6cm pT4pN0pM1 spindle intra-abdominal, renal, liver cKIT, CD117, CD34, vimentin AE1/AE3, SMA, S100, desmin

About 75% of GISTs are discovered incidentally and are less than 4cm in diameter. Of those that present clinically, the most common symptoms include GI hemorrhage and nonspecific abdominal pain. Obstruction is an uncommon presentation as these lesions have a tendency to grow in an extraluminal fashion. It has been postulated that the incidence of emergent presentations with GIST has increased. The majority of GIST lesions are benign (70-80%), however, all GISTs have the potential to become malignant. The incidence of metastasis at presentation of malignant GISTs can approach 50% as described in large clinical series. The liver is the most common metastatic site at presentation. And even though metastases to bone, lung, and lymph nodes have been described, they are distinctly uncommon. Because of the variable presentations and progressions of GISTs, it's important to be knowledgeable of this disease process and the indicated combined surgical and medical treatment.

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