Coccyx pain and MRI: precoccygeal epidermal inclusion cyst.

I commend Jaiswal et al on the highly illustrative case report entitled ‘Precoccygeal epidermal inclusion cyst presenting as coccygodynia’, published in your journal.(1) As the Director of the Coccyx Pain Service at a medical university, I wholeheartedly applaud the stepwise and thorough evaluation that these authors have provided for their patient, including obtaining a detailed history, performing a careful physical examination of the coccygeal region, obtaining seated radiographs in the lateral view to assess for dynamic instability and eventually proceeding to magnetic resonance (MR) imaging. I have encountered countless cases where patients present after having suffered with coccydynia (coccygodynia, or tailbone pain) for years, while most (and sometimes all) of the above investigative steps have been missed, often by multiple doctors. The case presented by Jaiswal et al demonstrates the importance of MR imaging in detecting pathology such as precoccygeal (retrorectal) masses that are missed on radiographs. I am frequently puzzled that physicians who routinely order lumbar MR imaging studies for patients with lumbar pain seem to forget to order pelvic/coccygeal MR imaging studies for patients with unexplained coccyx pain. Perhaps some physicians fail to fully investigate coccyx pain because they believe that no treatment is available, which is incorrect. Or perhaps some physicians mislabel their patients as having a neurotic, rather than physical, cause for their symptoms. More puzzling, I have seen many coccydynia cases where only “lumbar” or “lumbosacral” MR imaging studies had been ordered, neglecting to include the coccyx, and thus failing to visualise the patient’s symptomatic site. The precoccygeal mass in this case would not have been seen on a lumbar MR image. Again, I commend the authors and the journal for providing such a clear example of a thorough assessment, including the correct use of MR imaging studies, in the evaluation of coccyx pain.