Silent Phaeochromocytoma in a Young Normotensive Woman.

Phaeochromocytomas typically present with episodic palpitations, sweating and headaches, often with paroxysmal hypertension. In contrast, a smaller proportion are detected incidentally and may be normotensive, creating diagnostic challenges. We present the case of a 28-year-old British Indian woman who was incidentally found to have a right adrenal mass on computed tomography (CT) performed following an occupational abdominal injury. She was normotensive at the time and did not describe symptoms of classical catecholamine excess. However, she reported intermittent anxiety-like symptoms, which she attributed to work-related stress. Contrast-enhanced CT of the abdomen and pelvis revealed a 4cm right adrenal lesion with high attenuation of ~90 Hounsfield units (HU) and a heterogeneous appearance, raising suspicion of a non-adenomatous adrenal mass. Biochemical analysis demonstrated significantly raised plasma metanephrines on two separate occasions, consistent with phaeochromocytoma. Following multidisciplinary team (MDT) discussion, she was commenced on phenoxybenzamine and subsequently underwent an elective laparoscopic right adrenalectomy. Histology confirmed a completely excised phaeochromocytoma with low-risk features (Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) 2; Ki-67 <2%) and retained succinate dehydrogenase subunit B (SDHB) staining. Post-operatively, she remained normotensive, and follow-up plasma metanephrines were normal, with no evidence of residual disease. This case illustrates the diagnostic difficulties that can arise in normotensive, minimally symptomatic patients, and highlights the importance of systematic MDT evaluation of adrenal incidentalomas and cautious peri-operative planning, even in "silent" disease.