Imaging and pathologic correlation of composite pheochromocytoma-ganglioneuroma.

Abstract

A 50-year-old man consulted our institution for headaches and uncontrolled high blood pressure. Laboratory work-up and endocrine evaluation were consistent with pheochromocytoma with elevated plasma free metanephrine, free normetanephrine, plasma epinephrine, norepinephrine, total catecholamines, and 24-hour urine fractionated metanephrines, normetanephrines and total metanephrines levels. CT showed a contrast-enhancing 11.5 × 12.4 × 8.8 cm right adrenal complex cystic mass (Fig. 1A). Subsequent 68Ga-DOTATATE PET/CT confirmed the large right adrenal lesion with prominent tracer avidity (Fig. 1B). Surgical resection and pathology (Figs. 1C and 2) reached the diagnosis of composite pheochromocytoma-ganglioneuroma (CPG). The patient’s symptoms resolved after surgery. Genetic testing was normal. CPG, a rare tumor of mostly third-to-fifth decade of life with no gender preference, contains both pheochromocytoma (PC) and ganglioneuroma (GN) neoplastic components. CPG features symptoms of catecholamine overproduction: headache, palpitations, hypertension, and diaphoresis, and abdominal pain and watery diarrhea from excess VIP production by ganglioneuroma cells. CPG is indistinguishable from PC by clinical presentation, imaging features and biomarkers. Most CPG patients present with elevated catecholamines (1,2). CPG appears on CT as a well-circumscribed, heterogeneous or cystic adrenal mass with contrast enhancement. 68Ga-DOTATATE PET/CT may be an effective functional imaging modality for the detection and post-surgical monitoring of CPG based on its PC component (2). Diagnosis is histological with the identification of admixed regions of usually dominant PC and GN. PC cells stain positively for synaptophysin, GN cells with NeuN and Schwann cells with S-100. BRAF and HRAS mutations are frequently associated with CPG (3). CPG resection proceeds like PC surgery with preoperative adrenergic blockade, increased oral hydration and salt supplementation. The overall risk of malignancy associated with CPG is notably lower than with pure PC. Symptoms usually resolved upon CPG surgical resection, as seen in our case. One-out-of-eight treated patients may develop recurrence within 15 months (1).