From blazing to burnt out: Spontaneous regression of a testicular germ cell tumour

It is a rare, but recognised phenomenon that malignant testicular germ cell tumours can 'burn-out', where the primary lesion spontaneously regresses and presents with no viable remaining malignant cells leaving only a residual 'tumour scar', frequently in the context of distant metastatic disease.

We present a case report of a patient who underwent serial ultrasound scans documenting regression of a testicular lesion from a malignant appearance to a burned-out lesion, where subsequent resection and histology demonstrated features of a completely regressed seminomatous germ cell tumour with no residual viable tumour cells.

To the best of our knowledge, there are no previously documented cases where a tumour has been longitudinally followed from sonographic features of concern for malignancy to 'burned-out' appearances. Spontaneous testicular tumour regression has instead been inferred based on the presence of a 'burned-out' testicular lesion in patients presenting with distant metastatic disease.

This case provides further evidence supporting the concept of spontaneous testicular germ cell tumour regression. Ultrasound practitioners should be aware of this rare phenomenon in men presenting with metastatic germ cell tumour and, additionally, that this condition may present with acute scrotal pain.