An unexpected diagnosis of paediatric subcutaneous sacrococcygeal extraspinal ependymoma: lessons learnt and review of the literature

This case describes a 9-year-old male who presented to general surgical clinic with a 3-year history of persistent natal cleft swelling, previously unsuccessfully treated as a pilonidal abscess in the community with multiple courses of antibiotics. In clinic, a 50 × 30-mm soft tissue swelling was found in the natal cleft and a clinical diagnosis of a pilonidal cyst was made. A cream-coloured solid mass measuring 50 × 35 × 30 mm was subsequently excised under general anaesthetic, with specialist histology and immunostaining confirming an unexpected diagnosis of a subcutaneous extraspinal myxopapillary ependymoma, a tumour usually found in the neuraxis. Given the atypical anatomical site of the tumour, the case presented a unique management challenge. Ultimately, the patient underwent a re-operation after specialist multi-disciplinary discussion and is currently disease free at 18 months post-surgery. The authors wish to contribute their experiences of managing this rare extraspinal ependymoma to the few existing reports in the literature.