Hidden Dangers: A Gastrointestinal Stromal Tumor Concealed Inside of a Meckel's Diverticulum

Meckel's diverticulum (MD) is one of the most common congenital abnormalities of the gastrointestinal tract, affecting approximately two percent of the population. Rarely, Meckel's diverticula have been found to harbor various tumors, which go unnoticed until later in their course. The clinical presentation varies among each individual, and tumors have often metastasized or caused diverticular rupture at the time of diagnosis. This is a case of a 55-year-old male with a past medical history of alcohol abuse and asthma who presented to the emergency department with abdominal pain. He denied any fever, chills, chest pain, nausea, changes in urinary patterns, recent travel, or sick contacts. He is a non-smoker but has been a heavy drinker for many years. On physical exam, he was found to have diffuse abdominal tenderness with pain greatest in the epigastric region and no bowel sounds. He was afebrile but tachycardic at 112 bpm, hypertensive at 168/98 mmHg, and tachypneic at 38 bpm. Labs showed a markedly elevated white blood cell count, hemoglobin and platelet count, as well as metabolic acidosis and elevated lactate levels. Abdominal CT showed a mechanical small bowel obstruction with unclear etiology. Of note was a 7.2 cm thick-walled collection in the right lower quadrant having no clear communication with any bowel loops. Despite aggressive hydration and supportive care, his abdominal exam continued to worsen, prompting an exploratory laparotomy. During the laparotomy, a perforated MD with frank succus was found. On pathology, the affected segment of the bowel revealed a CD117 and CD34 positive spindle cell gastrointestinal stromal tumor (GIST) with mild cytological atypia, no necrosis, and no regional lymph node involvement. Cultures of peritoneal fluid were positive for Klebsiella oxytoca, and the patient was started on meropenem and doxycycline. The patient showed significant improvement with the appropriate administration of antibiotics and was eventually discharged to follow-up with hematology/oncology as an outpatient for further management and monitoring of his GIST tumor. This case is unique as there are only a few reported cases of patients developing GIST inside of MDs. Despite the high five-year survival rate of typically localized GIST tumors, the complications (such as perforation in the case of our patient) caused by tumor growth inside a MD are detrimental if not diagnosed promptly. Not only does perforation increase the risk of metastasis but also the risk of peritonitis and other complications. This case calls for more research on standardization of care for patients who have MD to prevent malignant transformations as well as potential prophylactic excision of incidental MD findings in adult patients.