Endocrine Abstracts

Introduction: Adrenal schwannomas are benign tumours originating from schwann cells within the adrenal gland. They are extremely rare, representing only 0.2-0.5% of all adrenal tumours. Fewer than 50 cases have been reported in the literature to date

Case report: We present the case of a 45-year-old woman with the first histologically confirmed adrenal schwannoma from our endocrine unit. She initially presented with elevated liver enzymes on routine blood tests, and she had noticed unintentional weight loss and palpitations alongside a growing pressure on the right side of her ribs over the past 18 months. Abdominal ultrasonography revealed a large solid mass in her right upper quadrant and a subsequent CT scan showed a 76mm well defined heterogenous right suprarenal mass. Serum biochemistry tests including renin-aldosterone, cortisol and dehydroepiandrosterone were all normal. Urinary metanephrines and steroid profiling were also normal. A FDG-PET scan was then done which showed a FDG avid right adrenal mass with no active distant disease. At this point our MDT favoured a non-functioning phaeochromocytoma however her MIBG scan revealed the mass to be non-tracer avid. She later underwent a successful right adrenalectomy with no postoperative complications. Immunohistochemistry demonstrated strong positivity for S100 and was negative for SMA, CD34, desmin, STAT-6 and myogenin confirming a diagnosis of adrenal schwannoma. Her post operative CT scan showed no evidence of recurrence.

Conclusion: This case underscores the diagnostic difficulties of adrenal schwannomas due to limited collective experience to draw upon and its resemblance with other adrenal masses. Patients are often asymptomatic with vague symptoms allowing the tumour to reach considerable size before diagnosis. Currently, formal diagnosis relies solely on surgical excision and histological examination to distinguish it from other, more common adrenal tumours. Our case reports adds valuable insight to the limited literature on the diagnostic challenges of this elusive tumour.