Ampullary Carcinoid Tumor: Diagnostic Challenges and Update on Management

Abstract

Purpose: A 65-year-old woman was referred with non-specific abdominal pain, slightly elevated amylase, MRCP findings of an ampullary mass (8×9 mm) with dilated intra-hepatic duct, common bile duct (CBD) and pancreatic duct (PD). An EUS revealed a bulging ampulla with submucosal hypoechoeic lesion, dilated CBD and PD, both tapering towards the ampulla. EUS-FNA was non diagnostic. Unable to cannulate during ERCP; pinch biopsies obtained from the ampulla (Figure 1) showed nests of cells positive for synaptophysin, suggestive of a carcinoid tumor. Patient underwent a Whipple procedure. Pathological evaluation revealed a 2×1.5 cm, well-differentiated neuroendocrine carcinoma (Figure 2) with tumor free margins. One of seven lymph nodes was positive for carcinoma. Two months after the surgery, patient was tolerating a regular diet with normal bowel function. Amongst diagnostic challenges, obtaining accurate tissue biopsies might be difficult due to submucosal proliferation of the tumor with normal epithelium. The sensitivity of an octreotide scintigraphy decreases with smaller size and decreased tumor somatostatin receptor expression. Diagnostic material obtained by EUS-FNA could be non-diagnostic. Unlike other midgut carcinoids, size of the ampullary carcinoid is a poor predictor of metastatic potential with varying rates of metastasis at different tumor sizes. To achieve a cure, a Whipple procedure with patient specific modifications is needed irrespective of the size of the ampullary carcinoid. Poor surgical candidates can be offered endoscopic or surgical ampullectomy. A recent study showed 100% sensitivity and specificity for predicting metastases among small intestinal carcinoids using gene expression profiling (GEP). Tumor risk stratification using GEP could potentially rescue some patients from undergoing a radical surgery.Figure: Two views of the bulging, enlarged ampulla of Vater.Figure: Ampullary carcinoid tumor showing nests and trabeculae of neuroendocrine cells with admixed dense fibrous stroma (H&E, 200X).