Ps-bpr01-2: pheochromocytoma with hyperaldosteronism-linked mutations in the potassium channel kcnj5

Context: Recent advances in genetic analysis techniques have led to the genetic analysis of adrenal tumors with hormone excess. In pheochromocytomas, many genetic abnormalities have been identified. Furthermore, several causative genes have been also reported in primary aldosteronism. We performed a comprehensive genetic analysis of functional adrenal tumors using next-generation sequencing. We report here a case of pheochromocytoma with KCNJ5 gene abnormality, which is considered to be specific for primary aldosteronism. Case: A 53-year-old woman with high blood pressure since age 48, excessive sweating and weight loss since age 52, and left ventricular hypertension noted on electrocardiogram during a medical checkup presented to her previous physician. A computed tomography scan of the abdomen showed a right adrenal tumor 30 mm in diameter, and an urinary test showed high levels of urinary metanephrine and normetanephrine (1.42 mg/day) and I-123 MIBG scintigraphy showed an accumulation at the tumor. Plasma renin activity was 0.2 ng/mL/hr, plasma aldosterone concentration was 73.9 pg/mL, and a positive captopril challenge test was performed. Adrenal scintigraphy using 131 I-adosterol showed bilateral adrenal accumulation, suggesting bilateral lesions. Laparoscopic right adrenalectomy was performed for pheochromocytoma. Histology showed focal proliferation of enlarged medullary-like cells and calcification of the adjacent adrenal tissue. The tumor tissue was positive for KCNJ5 gene mutation. A postoperative captopril challenge test was performed again, which was negative. Conclusion: KCNJ5 gene abnormality is considered specific for primary aldosteronism, but was also found in pheochromocytoma. However, the contribution of KCNJ5 gene abnormality to catecholamine production is not yet elucidated. This is a case of pheochromocytoma in which coexistence of primary aldosteronism is also suspected based on the captopril challenge test and imaging findings, and the finding of a gene mutation associated with primary aldosteronism in such a case is very interesting and will warrant further investigation.