A rare case of paraganglioma of the cystic duct.

INTRODUCTION: Biliary system paragangliomas are rare neuroendocrine tumors of embryonic neural crest origin. The majority is asymptomatic and incidentally found due to gallbladder functional disorders. Herein, we present a non-functional, 2.25 mm focus in the cystic duct, which to our knowledge, is the first reported paraganglioma of the cystic duct.

PRESENTATION OF CASE: The patient presented to the Emergency Department complaining of a sudden-onset, right upper abdominal and epigastric pain. Ultrasound and Computed Tomography were both consistent with signs of early cholecystitis. Laparoscopic cholecystectomy was performed without major complications. In addition to cholelithiasis and chronic cholecystitis, pathological examination reported a neuroendocrine proliferation in the cystic duct measuring 2.25 mm favoring paraganglioma. Incidentally, the patient is unique in that they were also found to have an adrenal nodule and a normocalcemic primary hyperparathyroidism that raised suspicion for an underlying endocrinopathy. Nevertheless, genetic testing was negative.

DISCUSSION: Extensive literature review demonstrates only nine cases of gallbladder paraganglioma, and three cases of hepatic ducts paraganglioma, but no cases of paraganglioma occurring at the cystic duct. Although a gene mutation and syndrome was not identified in the patient, the fact that an adrenal nodule and normocalcemic primary hyperparathyroidism were present, suggests that a complete hormonal workup should be obtained in these patients.

CONCLUSION: It is important to realize that biliary system paragangliomas, although rare, may occur. As they have an association with multiple endocrine neoplasia syndrome, a thorough endocrine investigation should be made.