Synchronous Malignant Pheochromocytoma With Renal Cell Carcinoma: A Case Report

Abstract

Introduction: In the US, Pheochromocytoma/paraganglioma incidence is estimated to be 2–8 per 1 million people each year with around 100–200 of these cases being malignant. Malignant pheochromocytoma is defined by documented presence of metastases or evidence of extensive local invasion. There are certain genetic syndromes which are also associated with renal cell carcinoma, including SDHB mutations type 4, VHL disease and familial pheochromocytoma. These syndromes are important to recognize as they may signify a worse prognosis. Here, we describe a case of co-occurrence of malignant PC with renal cell carcinoma.Case Report: A 53-year-old Hispanic male with history of HTN and recently diagnosed metastatic pheochromocytoma was admitted for surgical debulking of the left retroperitoneal/adrenal and renal masses. Symptoms began five months prior after he presented with an ischemic stroke in the setting of labile hypertension. He was diagnosed with a 6.3 x 4.6 x 6.8 cm incidental left retroperitoneal mass and suspicious left renal mass on CT imaging but also noted several lytic bony lesions concerning for bone metastasis. A spinal biopsy was obtained which was consistent with a well-differentiated metastatic neuroendocrine tumor. Laboratory evaluation was notable for Chromogranin A level of 6959ng/mL (25–140). He was started on Lanreotide. Given persistently difficult to control HTN he underwent work up for secondary hypertension. Hormonal evaluation was notable for plasma free metanephrine of 534pg/mL (<57pg/mL), normetanephrine 6155pg/mL(<148pg/mL), and total metanephrine of 6689pg/mL (205pg/mL) consistent with metastatic Pheochromocytoma. After appropriate alpha blockade he underwent left adrenalectomy, nephrectomy and liver tumor microwave ablation. Pathology was consistent with an 8.7cm pheochromocytoma with extensive retroperitoneal soft tissue invasion and PASS score of 9 as well as a 3.6 cm renal cell (clear cell-papillary type) carcinoma. On follow up, Plasma metanephrine decreased significantly postoperatively to a free metanephrine of 28pg/ml, normetanephrine 1153pg/ml, and total metanephrine of 1181pg/mL. He was referred for genetic testing but unfortunately, he was readmitted one month later with cerebral hemorrhage and expired.Conclusion: Advancements in genetics have led to improved understanding of the molecular etiologies of pheochromocytomas. A number of genetic defects are associated with PC and RCC, including SDHB mutations type 4, VHL and familial pheochromocytoma. Our case underscores the high morbidity and mortality in patients with metastatic PC with RCC and perhaps the catastrophic outcomes in such patients. Assessing patient’s genetics in these cases is now the standard of care, however further research studies are warranted to better understand the significance of tumor genetics on prognosis and management.