Coccygeal tumours unveiled: a retrospective cohort analysis from a tertiary referral centre.

Background: Isolated tumours affecting the coccyx are infrequent, with only a handful of documented cases in the literature. Herein, we highlight the most extensive consecutive case series involving various isolated coccyx tumours with varied clinical presentations and imaging features.

Methods: A retrospective search of our tertiary Orthopaedic oncology institute's oncology and Radiology database [Radiology Information System, Picture Archiving and Communication System, and Computerised Radiology Information System] for the keyword "Coccyx" and "Tumour" was performed over 15 years (between December 2007 and August 2022). Data collected was correlated with local histopathology and laboratory records. Patient demographics, clinical characteristics, and complementary imaging findings were recorded for analysis.

Results: One hundred and three lesions originating in the coccyx with a mean age of 62 years (range 25-90 years) were identified. There was a male preponderance with 59 male and 44 female patients (1.3:1.0). The most typical tumour noted was chordoma. Other lesions included a dermoid cyst, a myxopapillary ependymoma, a notochordal remnant, an osteochondroma, an Ewing sarcoma, and a teratoma.

Conclusion: Our analysis suggests that most of the tumours involving coccyx are chordomas with a few rarely encountered benign and malignant tumours. Radiological imaging plays a vital role in characterising isolated tumours affecting the coccyx and guiding appropriate patient management.

Advances in knowledge: This is the largest reported series of coccygeal tumours. Chordoma is the commonest coccygeal tumour. Patients with unexplained coccydynia should undergo detailed investigations, preferably with cross-sectional imaging.