Testicular adrenal rest tumours (TART) are rare cancers mainly associated with congenital adrenal hyperplasia in its classic form, with a prevalence of up to 40% of patients, particularly in those with inadequate control of their illness.1 Although rare, they can also occur in other diseases associated with high ACTH concentrations.2, 3, 4, 5

The lesions can be confused with Leydig cell tumours, for which patients may end up having a gonadectomy. It is therefore important to be aware of the possibility of TART, as treatment should be conservative with the objective being to preserve fertility.

We present this case of TART in a patient with Addison's disease; the second to be reported in the literature.