Chronic Abdominal Pain: “The Great Masquerader”

CASE PRESENTATION A twenty-seven-year-old African American gentleman was evaluated for abdominal pain of seven years duration. The pain initially began when the patient was running quickly for exercise. Subsequently, it progressed such that walking precipitated abdominal pain. He had three previous episodes of bilious emesis without any prior history of peptic ulcer disease or associated abdominal pain. During the past year, he also had 10 pounds of unintentional weight loss. The patient denied hematemesis, melena, and hematochezia. His medical history consisted of hypertension, diagnosed two years prior and treated with lisinopril and metoprolol, and asthma that was well controlled. He denied use of non-steroidal anti-inflammatory medications and had no drug allergies. His only prior surgery consisted of an anterior cruciate ligament repair of the left knee. Family history was negative for malignancy. Social history was positive for alcohol (6 drinks on weekends) and tobacco use (4 pack year history) and negative for drug use. His review of systems was positive for headaches, nausea, vomiting, anxiety, depression, chest pain, abdominal pain, and asthma. Physical examination revealed a normal blood pressure but he was tachycardic with a heart rate of 115. He had a thin and muscular abdomen that was soft, nontender and non-distended on exam; there was no hepatosplenomegaly and there were no hernias. As part of the initial evaluation of his abdominal pain, esophagogastroduodenoscopy (EGD) was requested. Despite adequate sedation, the EGD was unable to be performed as the patient became very combative and agitated. As such, an upper GI with small bowel follow through (SBFT) was ordered; the findings were unremarkable. Routine labs including a complete blood count (CBC), complete metabolic panel (CMP), erythrocyte sedimentation rate (ESR), iron studies, thyroid stimulating hormone (TSH), cobalmin (B12), and H. pylori stool antigen were all normal or negative. Transabdominal ultrasound revealed an oval,wellcircumscribed mass along the anterior margin of the aorta in the retroperitoneum that was contiguous with the head of the pancreas. Subsequent abdominal CT scan confirmed presence of a large (heterogeneous) intensely enhancing mass in the retroperitoneum measuring 5 3.8 5 cm. The lesion was situated in the area of the inferior vena cava, with possible compression of this vascular system. Differential diagnosis, based on imaging studies, included lymphoma, sarcoma, and angiosarcoma. Decision to pursue CT guided biopsy of the lesion was contemplated; however, after further discussion with a radiologist, a new diagnosis of pheochromocytoma was postulated. As pheochromocytomas are highly vascular, the biopsy was cancelled because of concern for increased risk of bleeding. Laboratory markers (Table 1) confirmed the diagnosis of pheochromocytoma. Once the diagnosis of pheochromocytoma was confirmed, Multiple Endocrine Neoplasia (MEN) 2a syndrome was excluded with normal intact parathyroid home (PTH) and calcitonin levels. Positron emission tomography (PET) computed tomography (CT) revealed significant fluorodeoxyglucose (FDG) activity limited to the retroperitoneal mass without metastases. Although the high FDG activity was suspicious for malignancy, the lack of metastases favored a diagnosis of benign pheochromocytoma. A hematology oncology consultation was obtained and further patient history was elucidated. It was discovered that the patient’s mother had a pheochromocytoma that was resected when she was 25 years-old, thus his A CASE REPORT