A 72-year-old man presented with a two-year history of hot sweats, impotence and mood swings. He had a past medical history of polymyalgia rheumatica, osteoporosis and mild hypercalcaemia.
On examination he was sweating excessively, had testicular atrophy and mild hypertension. Blood tests revealed a raised LH, FSH and a low testosterone consistent with primary hypogonadism. Hypercalcaemic screen was negative. He was started on androgen replacement therapy as well as anti-hypertensives with subsequent readings in normotensive range.
He re-presented again to clinic a year later with recent onset palpitations, hot sweats and persisting hypercalcaemia. Systemic examination was unremarkable. A 24-hour electrocardiogram was normal. Paroxysmal hypertensive episodes were noted by GP inspite of being on antihypertensives. Phaeochromocytoma was suspected and 24-hour urinary catecholamines were elevated.
An MRI scan showed a right adrenal mass with no extra-adrenal foci while a MIBG scan (metaiodobenzylguanadine) later demonstrated increased uptake on the left side.
A CT scan subsequently supported the presence of a Phaeochromocytoma on the right side as well as differentiating the mass from an adenoma. It further confirmed the absence of any adrenal mass on the left side.
He was started on alpha-beta blockade and had a successful laparascopic right adrenalectomy.
Post-operatively, his symptoms resolved (hot sweats and palpitations). He remains normocalcaemic and normotensive.
Conclusion:The delayed diagnosis of Phaeochromocytoma was partly due to the presence of primary hypogonadism and the supportive features associated with it. Though phaeochromocytomas are uncommon, if not diagnosed early can be fatal and should be investigated with any overlap of symptoms.
MIBG scans are known to have a significant false negative rate. False positives are rare and to have both false positive & false negative in a single case has not been reported before. A case of dual pathology, Phaeochromocytoma as well as Hypogonadism leading to a delay in diagnosis of phaeo due to overlap of symptoms.
Difficulty in localisation of tumour due to both false positive and false negative MIBG scan in same patient which has not been reported before.