A Rare Case of Abdominal Pain: EUS Diagnosed Adrenal Myelolipoma

Abstract

Purpose: A 45 year old male presented with one week of severe epigastric pain, nausea, and vomiting. The pain was constant, sharp, and radiated to his back. He was unable to tolerate oral intake and also complained of severe, watery diarrhea occurring approximately 8-10 times per day. Review of systems was notable for fatigue, muscle cramps, and lower extremity edema. Past medical history was significant for familial pancreatitis with frequent flares, diabetes, and cholecystectomy. Numerous diagnostic and therapeutic interventions had been performed over the years in order to evaluate his abdominal complaints. He underwent an exploratory laparotomy with cholecystectomy, hernia repair, and pancreatic stenting to help alleviate his discomfort. During this time, CT scan revealed a left sided incidental adrenal mass which was being followed conservatively with serial imaging. Physcial exam revealed a soft, non-distended abdomen which was exquisitely tender in the epigastrum and left upper quadrant. There was no rebound or guarding. The patient was admitted to the hospital for further assessment. Laboratory data included an alkaline phosphatase level of 502, total bilirubin of 6.8, and lipase level of 10. CT scan revealed an enlarging left adrenal mass measuring 10.4 × 5.8 × 9.4 cm and a new hypodense, obstructing mass in the area of the pancreatic head measuring 4.4 × 3.3 cm that had not been seen six months prior. EUS exhibited an irregular hypoechoic and heterogenous mass with irregular borders in the pancreatic head and a 10.5 cm × 5.8 cm hyperechoic mass in the left adrenal gland. FNA and pathology of the gland showed abundant marrow elements, including megakaryocytes and fat consistent with a myelolipoma. The patient underwent ERCP with stenting and sphinchterotomy in addition to left adrenalectomy and mobilization of the splenic flexure. Myelolipomas are well-circumscribed lesions that contain mature adipose tissue intermixed with mature myeloid elements. Autopsy studies have reported that the estimated incidence in the general population is less than 0.2%. Most are discovered incidentally through imaging or surgery, but some patients do present with abdominal pain secondary to mechanical compression, hemorrhage, or tumor necrosis. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy allows the detailed imaging and FNA not only of both intramural and extramural structures and lesions of the gastrointestinal tract but also of various intraabdominal organs. Recent studies have proven the efficacy of this highly specific and safe technique for cytopathologic assessment of both primary and metastatic disease.