Incidental phaeochromocytoma in an unsuspecting urological setting
M S Siddiqui, K Muralidhara, Central Middlesex Hospital, London Northwest Healthcare NHS Trust
A sixty five year old gentleman was admitted under urology with generalised abdominal pain, haematuria on urine dipstick and mild acute kidney injury. USS abdomen revealed a left sided hydronephrosis which was confirmed on CT urogram. The scan also showed an incidental right sided 3.5 cm adrenal lesion which was denser than 10 Hounsfield units and did not wash out well on contrast imaging. He was known be hypertensive for nine years, well controlled on amlodipine monotherapy.
The patient underwent outpatient urological interventions in the subsequent months including dilatation of a urethral stricture, left ureteric biopsy and insertion of a left ureteric JJ stent. Two 24 hour urine samples collected six months after his initial presentation showed very high metanephrine levels at more than four times the upper limit of normal range. Plasma metanephrines were elevated at 55747 pmol/L (NR 0 Ė 510pmol/L). Of note, he had no symptoms of hormonal excess and was normotensive during all clinical assessments.
MIBG Iodine 123 SPECT CT scan showed increased uptake in right adrenal lesion consistent with a phaeochromocytoma. Subsequent CT chest and NM Ga68 DOTATATE PET scan didnít demonstrate any paragangliomas or distant metastases.
He was adequately alpha blocked with phenoxybenzamine and underwent laparoscopic right adrenalectomy. Histology confirmed phaeochromocytoma with PASS score of 5. The genetic testing for associated familial syndromes is awaited. The cause for the left sided hydronephrosis remains unknown and he awaits a left nephrectomy for minimally functioning left kidney.
Phaeochromocytomas are rare endocrine tumours and can easily be missed in a non-specialist setting. The case demonstrates the importance of investigating all adrenal incidentalomas for hormonal excess and assessment by endocrinologists, as recommended in the guidelines. Normotensive phaeochromocytomas have roughly similar per-operative hemodynamic instability comparing hypertensive phaeochromocytomas and therefore require adequate alpha and beta blockade. Luckily, our patient underwent major urological interventions without developing a potentially serious hypertensive crisis.