S3455 Unusual Presentation of a Young Male Diagnosed With a Perforated Gastrointestinal Stromal Tumor (GIST) in the Jejunum With a Previous History of Multiple Myeloma (MM)

Abstract

Introduction: Studies suggest an increase in the frequency of additional malignancies in patients with GIST. This relationship remains unclear and needs further exploration. We present a case of GIST in a patient with Multiple Myeloma. Case Description/Methods: A previously healthy 38 years old male presented in 2016 complaining of weakness, fatigue, and back pain; he was diagnosed with Multiple Myeloma. Remission was achieved using chemotherapy and autologous bone marrow transplantation. He had a relapse of Multiple Myeloma on a bone marrow biopsy in 2020. Since then, he has been receiving chemotherapy. In March 2022, he presented to the ER complaining of abdominal distension, severe pain, and vomiting, based on a physical exam and CT. Scan, he was diagnosed with small bowel obstruction and peritonitis. Surgical exploration revealed a large abdominal perforated mass originated from the proximal jejunum, with adhesions to the root of the mesentery, urinary bladder, small bowel, transverse, descending, and sigmoid colons. Excision of the mass with resection of about 30 cm and re-anastomosis of the jejunum was performed. Postoperatively, the patient was admitted to the ICU for three days to control cardiac arrhythmia. He was discharged from the hospital ten days later. Pathology confirmed the diagnosis of GIST. Currently, the patient is receiving chemotherapy and doing well (Figure). Discussion: Despite being the most common mesenchymal neoplasms of the gastrointestinal tract, GIST are still rare tumors that account for less than 1% of all GI tumors; they occur mostly in the stomach or small intestines. The average age of diagnosis is 50-70 years and is considered non-hereditary or sporadic. There are reports of co-existing GIST with adenocarcinomas within the GI tract or distant organs. In a single case series of 43 patients with GIST, 6 (14%) had an additional primary tumor, five within the GI tract. In a larger population-based study with 6,112 GIST patients, 1,047 (17.1) had additional cancers. Despite that, so far, only one case of (MM) was reported in a patient with GIST in 2007 in Greece, which ended with the patient’s death six months after the diagnosis of (MM). This case highlights the relationship between GIST and other primary neoplasms at a young age. It is unclear whether the GIST was due to genetic association, environmental exposure, or chemotherapy. Clinicians should look for tumors within or outside the GI tract, which could significantly affect the prognosis.Figure 1.: Resected GIST from with 30 Cm of the jejunum.