Nerve sheath tumours originate from myelin that surrounds peripheral nerves and include schwannomas and neurofibromas. They can occur sporadically or as part of neurofibromatosis 1 or 2. Very rarely, they have been described to arise from the viscera including the adrenal gland. It is thought that they arise from Schwann cells around nerve fibres that supply the adrenal medulla. These are rather slow growing and non-functioning adrenal tumours that can be found incidentally or present as a result of compressive symptoms.
We describe the case of a 30 year old lady who was noted to have an incidental 11 cm by 9 cm unilateral adrenal lesion on a CT scan performed to stage her lymphoma. An overnight dexamethasone suppression test, a renin:aldosterone ratio and 24 h urine metanephrine were normal. She had no clinical signs to suggest neurofibromatosis and had no family history of note. A core biopsy revealed spindle cells that were strongly positive with S100 immunostaining and show a very low proliferative index with Ki-67 of <1 in keeping with a benign nerve sheath tumour. She has been managed conservatively.
Large mixed attenuated lesions arising from the adrenal gland on imaging may raise the suspicion of malignancy. Biopsy in this case is helpful as the patient is asymptomatic and surgery is mostly carried out if there is any evidence of compression of adjacent vital structures.