Urinary AVP/Cr at first morning void may have potential clinical value as a predictor for responsiveness to low-dose desmopressin in nocturia with NP.

IntroductionComposite pheochromocytoma is a rare tumor, occurring in only 3% of pheochromocytomas. We report a case of composite pheochromocytoma with neurofibromatosis type 1.Case presentationA 42‐year‐old man was referred to our department for further evaluation of an incidentally detected right adrenal tumor. He was a patient at another hospital for neurofibromatosis type 1. The serum and urinary catecholamine levels exceeded the normal range. Abdominal computed tomography and magnetic resonance imaging showed a 2.8 cm diameter right adrenal tumor, and 123I‐metaiodobenzyguanidine scintigraphy showed radioisotope uptake. He was diagnosed with pheochromocytoma and underwent a right laparoscopic adrenalectomy. Histopathological examination revealed that the tumor consisted of a pheochromocytoma and ganglioneuroma. The final diagnosis was composite pheochromocytoma‐ganglioneuroma. Five years after surgery, no recurrence was observed.ConclusionPreoperative diagnosis of composite pheochromocytoma‐ganglioneuroma is difficult; therefore, histopathological examination is necessary for a definitive diagnosis. Pheochromocytoma management requires lifelong follow‐up.