Endocrine Abstracts

Case: A 75-year-old male patient was treated for lung adenocarcinoma 12 years ago. During the routine imaging studies of the patient who was followed without treatment after curing, a suspicious, non-adenomatous lesion in the right adrenal gland, 16×9 mm in size was detected by thoracic computed tomography. Serum aldosterone/renin ratio and urine catecholamine tests were normal with no complaints of suspicion for pheochromocytoma. F18FDG PET-CT showed an increase in metabolic activity (SUVmax:4,8) in the right hilar region. The cytological examination was benign with bronchoscopy. Laparoscopic right adrenalectomy was performed because no other lesions were detected. Histopathologic examination revealed non-invasive pheochromocytoma showing positive staining with synaptophysin and chromogranin.

Discussion: Pheochromocytoma is very rare in adrenal incidentalomas, however, can be asymptomatic at rates up to 10%, as they can manifest with attack symptoms or less with persistent hypertension. It is suggested that catecholamine synthesis is defective in these tumors. In some reports it is specified that, this phenomenon may be seen in some mutations in the succinate dehydrogenase gene. In some reports, however, about 10–20% of silent pheochromocytomas were reported to be due to laboratory error. On the other hand, non-adenomatous lesions in the adrenal glands in a patient known as primer malignancy are generally considered as metastases. In our case, the patient was referred to a similar presentation and it was initially thought that the lesion may be a metastatic lesion. However, the fact that the primary malignancy has been in control for more than 10 years has been questioned about metastasis. One of the methods that can be applied in such a case is biopsy but pheochromocytoma should be firstly excluded. In this case report, we have demonstrated that; in non-adenomatous adrenal lesions, the absence of clinical signs and normal catecholamine levels do not exclude pheochromocytoma.