MON-389 Normotensive Pheochromocytoma

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Background: Pheochromocytoma is a rare neuroendocrine tumour arising from chromaffin cells of the adrenal medulla that produce catecholamines and their metabolites. It accounts for up to 5-9% of adrenal incidentalomas (AI). Lack of hemodynamic features including hypertension has been reported in 13.5% to 55% of incidental pheochromocytoma series. It is postulated that normotensive pheochromocytoma (NP) silent presentation might be caused by reduction in secretion of catecholamines. Adrenalectomy is the treatment of choice for normotensive pheochromocytoma. Pre-operative pharmacological blockade for NP is still controversial. Clinical case: A 39 years old lady Admitted with perforated Appendix was referred to the endocrine service for incidentally discovered left adrenal mass .Patient has no history suggestive of adrenal hyper functioning. No family history of endocrine disorders. Physical examination showed blood pressure of 90/60 mmHg with no signs of adrenal hyper functioning. CT scan showed, left adrenal mass measuring 6 X 4.1 x 4.7 cm with multiple central necrotic areas and heterogenous enhancement. MIBG scan showed a large focus of uptake in the left adrenal area. Laboratory investigations showed normal DST. Plasma metanephrines were 1850 ng/l (normal less than 90 ng/l) and normetanephrines were 3050 ng/l (normal less than 129 ng/ml). 24 hours urine adrenaline was more than 213 nmol/24 h (normal less than 147), metanephrines was more than 17.7 umol/l (normal is less than 2.04) and normetanephrine more than 15.79 umol/l (normal is less than 4.40). Patient had left laparoscopic adrenalectomy with no complications. She did not receive any pre-operative pharmacological blockade as she couldn't tolerate any. Histopathology showed pheochromocytoma 7 cm in diameter with no central necrosis, mitotic count was 1% per HPF, no Atypical mitosis, no vascular or capsular invasion, no extension. Genetic screen was negative. Conclusions: Screening for pheochromocytoma is mandatory for all adrenal incidentaloma even in the absence of hypertension as Lack of hemodynamic features has been reported in 13.5% to 55% of incidental pheochromocytoma series.