Incidental Detection of Synchronous Medullary Thyroid Carcinoma with Bilateral Adrenal Pheochromocytoma on Iodine-123 Metaiodobenzylguanidine Scintigraphy, Leading to Diagnosis of Multiple Endocrine Neoplasia 2A.

We report a case of a 29-year-old female with the family history of medullary thyroid carcinoma (MTC) presenting with hematuria and tachycardia, who was found to have bilateral adrenal masses on abdominal computed tomography and biochemical testing compatible with pheochromocytoma. Iodine-123 (I-123) metaiodobenzylguanidine (MIBG) scintigraphy for preoperative planning prior to planned adrenalectomy revealed incidental synchronous unifocal MTC, along with expected bilateral adrenal pheochromocytomas. Pathology confirmed these findings, and subsequent genetic testing confirmed a rearranged during transfection proto-oncogene mutation on exon 11, confirming the clinical diagnosis of multiple endocrine neoplasia 2A (MEN 2A). The unexpected incidental finding of synchronous MTC highlights the importance of considering MEN in the differential diagnosis when encountered with newly diagnosed pheochromocytoma and highlights the utility of I-123 MIBG scintigraphy in diagnostic workup of newly diagnosed pheochromocytoma.

Dumbbell Gallbladder Cholecystitis on Tc-99m Diisopropyliminodiacetic acid Hepatobiliary Imaging.

We present a case of a 79-year-old immunocompromised female admitted for abdominal pain and sepsis, who had an abdominal computed tomography (CT) showing distal gallbladder fundus wall thickening, pericholecystic edema, and a right posteroinferior hepatic abscess. Subsequent hepatobiliary scintigraphy with Tc-99m diisopropyliminodiacetic acid showed gallbladder filling of the proximal gallbladder fundus, yet no radiotracer filling of the distal gallbladder fundus. Further correlation with the initial CT showed a partial gallbladder stricture and a resultant altered morphology resembling a dumbbell-shaped gallbladder. Percutaneous cholangiogram also confirmed this dumbbell morphology. Nonfilling of radiotracer into the distal end of the dumbbell gallbladder correlating with CT findings of focal gallbladder inflammation indicated that there was a focal inflammation suggesting a distal dumbbell gallbladder cholecystitis. This case demonstrates a unique finding of focal inflammatory pathology involving an anatomic variant - the dumbbell-shaped gallbladder, and the challenges this anatomic variant presents in hepatobiliary scintigraphy image interpretation.

Extramedullary Plasmacytoma of the Gallbladder Detected on Fluorine 18-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Extramedullary plasmacytoma is rare in patients with diagnosed multiple myeloma. Soft tissue plasmacytoma of the gallbladder is particularly uncommon and has been described in only a handful of cases. Diagnosis of gallbladder plasmacytoma with fluorine 18-fluorodeoxyglucose (F18-FDG) positron emission tomography/computed tomography (PET/CT) has not previously been reported. We present a 65-year-old female with a history of multiple myeloma who underwent a restaging F18-FDG-PET/CT which showed a focal area of hypermetabolic activity, corresponding to a nodular lesion within the posterior gallbladder wall. The patient underwent successful cholecystectomy, with surgical pathology revealing gallbladder plasmacytoma. A follow-up scan was negative for active malignancy. This is a novel case of gallbladder plasmacytoma diagnosed on whole-body F18-FDG PET/CT - thus demonstrating the clinical value of this imaging modality in staging, restaging, and surveillance for patients with multiple myeloma.