ESRA19-0485 Underdiagnosed bone metastatic cancer in a patient with coccygodynia

Background and aims Coccygodynia is a painful condition affecting the coccyx region. The most common cause is traumatic origin that might result from falls in the sitting position, repeated microtrauma attributable to inadequate body positioning while seated,1 but it should be differentiated from neuropathic and visceral origin. We report a case of coccygeal metastatic cancer that occurred in an 87-year-old female patient who had been healthy for 10 years after complete remission from rectal cancer. Her chief complaint was simple pain in coccygeal area, but there were no any other associated symptoms. Sonogram for nerve block showed irregularity of the bone cortex, and she was diagnosed with coccygeal metastasis. Even though osseous metastasis from colorectal cancer is a rare condition, with reported incidence of 5–10%,2 physicians should consider cancer metastasis as one of the possible causes of the pain. Conclusions When some causes other than trauma are suspected for coccygodynia, more detailed diagnostic procedure and referral must be done to rule out metastatic malignancies.