Charlotte Gastroenterology and Hepatology Matthews, NC
Mukti A. Patel, MD1, Natalie Nowak, DO2, Dhwani Mehta, MD3, Viral Patel, MD4; 1Saint Louis University Hospital, St. Louis, MO; 2Surgical Specialists of Charlotte, Matthews, NC; 3Dermatology Group of the Carolinas, Concord, NC; 4Charlotte Gastroenterology and Hepatology, Matthews, NC
Introduction: Small bowel obstruction (SBO) is a known complication of Roux-en-Y gastric bypass (RYGB), commonly involving the Roux limb with typical obstructive symptoms. Here, we report a rare case of obstruction in the biliopancreatic limb secondary to metastatic melanoma, without classic obstruction symptoms.
Methods: A 55-year-old man with PMH of atrial fibrillation on Apixaban, remote RYGB, and distant Stage 2A melanoma with negative sentinel lymph node biopsy presented after a large amount of dark red stool and diarrhea. He denied nausea, vomiting, weight loss, abdominal pain, or NSAID use. Labs revealed iron-deficient microcytic anemia (Hb 6.3, MCV 71). CT angiogram showed small bowel intussusception without obstruction. EGD and colonoscopy revealed multiple large pedunculated colon adenomatous polyps which were removed and indicated in his anemia. The patient presented the hospital 3 months later with lightheadedness, and severe iron deficiency anemia on labs (Hb 4.7, MCV 66), otherwise asymptomatic. During outpatient follow-up 2 months later, he reported new left-sided cramping and unintentional weight loss. Small bowel series showed proximal jejunal intussusception with progressive dilatation of the jejunum proximal indicating obstruction. Surgery revealed a 6cm polypoid lesion in the biliopancreatic limb with resection pathology revealing a metastatic malignant melanoma. Discussion: Small bowel obstruction after RYGB can be devastating without early recognition and intervention. Common causes include internal hernias, adhesions, and jejunojejunal strictures, while volvulus and intussusception are rare. Patients with intussusception typically present with symptoms of SBO, including nausea, vomiting, and abdominal pain. Unfortunately, altered anatomy after gastric bypass surgery can skew the presentation, making both clinical and radiologic diagnosis a challenge. Moreover, obstruction typically involves the Roux limb, which connects the new gastric pouch to the small intestine, and involvement of this limb would theoretically lead to “obstructive” symptoms. In our patient, the biliopancreatic limb, which is connected to the gastric remnant, was the site of the melanoma mass. This led to non-specific symptoms, making early diagnosis clinically challenging. Variability in post-RYGB obstruction symptoms and difficult access to the biliopancreatic limb, increases the importance of imaging. Prompt surgical consultation can prevent morbidity and improve overall patient outcomes.