Positron emission tomography with 18F-fluorodeoxyglucose is a useful tool for the diagnosis of pheochromocytomas without distant metastasis, where malignancy is suspected on the basis of histopathologic analysis.

A 69-year-old woman, who had been undergoing treatment for hypertension, was admitted to the hospital for the evaluation of a tumor in the right adrenal gland and of episodic hypertension. She was diagnosed with pheochromocytoma on the basis of elevated urine catecholamine and metabolite concentrations and positron emission tomography (PET) results; however, the results of I-metaiodobenzylguanidine (I-MIBG) scintigraphy were negative. The patient underwent laparoscopic right adrenalectomy. Malignancy was suspected on the basis of histopathologic studies. After surgery, the elevated catecholamine and metabolite concentrations and the blood pressure returned to normal; furthermore, the symptoms, including severe headache, reduced. The authors report a case of pheochromocytoma that was suspected to be malignant on the basis of histopathologic analysis and was detected by F-fluorodeoxyglucose (FDG)-PET but not by MIBG. Thus, FDG-PET may be a prognostic marker for malignant pheochromocytomas with or without metastasis.

Misdiagnosis of two cases of primary aldosteronism owing to failure of computed tomography to detect adrenal microadenoma.

Recent studies have suggested that primary aldosteronism (PA) is a common form of hypertension. However, some cases of PA are overlooked because microadenoma is difficult to detect by imaging. The author report 2 cases in which aldosterone-producing microadenoma was diagnosed by selective adrenal venous sampling (AVS) and furosemide plus upright test. These adenomas were resected by laparoscopic adrenalectomy. Both cases presented with hypertension and hypokalemia. Experimental data, including those obtained from furosemide plus upright test, suggested PA. In both cases, computed tomography imaging revealed a normal adrenal gland without any tumor. However, selective AVS indicated unilateral hypersecretion of aldosterone. Laparoscopic adrenalectomy was performed, and clinical symptoms of the patients improved. The histopathologic findings revealed aldosterone-producing microadenomas with diameters of 6 and 3 mm, respectively, in cases 1 and 2. In conclusion, AVS should be performed to confirm the diagnosis of PA when computed tomography imaging does not provide definite results.

Improvement in renal dysfunction and symptoms after laparoscopic adrenalectomy in a patient with pheochromocytoma complicated by renal dysfunction.

A 70-year-old patient who was undergoing treatment for diabetes mellitus and chronic hepatitis was admitted to our hospital for evaluation of a tumor in the left adrenal gland (50 x 45 mm) and renal failure. On the basis of the patient's increased serum concentrations of catecholamines and other metabolites and the results of positron emission tomography (PET), the patient was diagnosed with a pheochromocytoma; iodinated metaiodobenzylguanidine ([(131)I]MIBG) scintigraphy was insufficient to establish this diagnosis. Subsequently, he underwent surgery for tumor resection. Histological examination suggested the tumor to be a malignant pheochromocytoma. After left adrenalectomy was performed, the elevated catecholamine and metabolite concentrations and the blood pressure were restored to normal, and the patient's symptoms of severe headaches and vertigo reduced. Furthermore, his renal function improved (Cr 2.0-1.2 mg/dl). Our patient exhibited a rare condition of pheochromocytoma complicated by renal failure, which was successfully treated with laparoscopic surgery.