Marker-Negative Pheochromocytoma Associated with Inferior Vena Cava Thrombosis.

Pheochromocytoma associated with inferior vena cava (IVC) thrombosis is very rare. A 27-year-old female presented with right flank pain and hypertensive urgency. Contrast-enhanced CT abdomen and gadolinium-contrast MRI abdomen revealed right adrenal mass suspicious of malignancy with invasion and compression to the right IVC wall along with IVC thrombus extending from the level of renal veins to the level of confluence with hepatic veins. Her routine laboratory investigations including 24-hour urine fractionated metanephrines, vanillylmandelic acid, and cortisol were normal. Right adrenalectomy with IVC thrombectomy was done. Perioperative period was uneventful. Histopathology of the mass turned out to be pheochromocytoma with thrombus revealing fibroadipose tissue with fibrin. Pheochromocytoma may present with IVC thrombus as well as normal serum and urinary markers. Thus, clinical suspicion is imperative in perioperative management of adrenal mass.