Background: Benign cortical and medullary tumours, adrenocortical cancers (ACC), bilateral adrenal hyperplasia, adrenomyelolipomas and metastases are commonly discussed in the differential diagnosis of a tumour in the adrenal bed. This study reports a series of non-adrenal tumours encountered during surgery for expected adrenal tumours.
Method: Retrospective review of surgical practice in a tertiary referral centre.
Results: Between 2014 and 2018 the annual workload for adrenal surgery ranged 6075. In this large cohort of over 300 patients, a small minority of patients (n=15) had unexpected histological diagnoses. Eight patients with median age 29 years had ganglioneuromas (5R:1L). Five patients with median age 75 years had large retroperitoneal schwanomas initially suspected to be ACC based on PET activity (3R:2L). Two patients age 58 years old with left-sided tumours had a GIST (gastrointestinal stromal tumour) measuring 55 and 150 mm. A 12-cm left adrenal teratoma was excised in a 27 years old woman, a bronchogenic cyst and a hemangioma were diagnosed as left-sided phaeochromocytomas based on mild biochemical abnormalities and positive MIBG uptake.
Conclusion: Retroperitoneal tumours should be considered in the differential diagnosis of non-functional large (adrenal) mass. Ganglioneuromas were more common in younger patients and schwannomas in older patients. Functional imaging with C11-metomidate might become a useful adjunct in differentiating cortical adrenal tumours from other retroperitoneal tumours.