Background <p>The etiology of pediatric coccydynia is complex. While it is most frequently caused by trauma, a significant proportion of cases are idiopathic, primarily attributed to poor intercoccygeal joint stability and hypermobility of the coccyx. Herein, we report the first case of pediatric coccydynia resulting from a localized developmental anomaly of the coccyx.</p> Case presentation <p>A 13-year-old Asian girl was admitted to the hospital owing to 1 year of coccygeal pain during defecation. A computed tomography scan of the sacrococcygeal region revealed a slender protrusion anterior and slightly to the right of the first coccygeal vertebra, extending obliquely in an anteroinferior direction. Pathological findings confirmed it as a normal bony structure. Due to poor response to conservative treatment, the surgeon performed a partial coccygectomy under general anesthesia on the pediatric patient. The procedure involved resection of all bony structures distal to the midportion of the first coccygeal vertebra, including the abnormal protrusion. Intravenous cefuroxime sodium (1&#xa0;g) was administered within 24&#xa0;h postoperatively to prevent surgical site infection. The procedure was performed successfully without complications, and the pediatric patient was discharged on the fourth postoperative day. At the 1-month postoperative follow-up, the child reported no significant discomfort.</p> Conclusion <p>This case provides new insights into the etiology and pathogenesis of coccydynia.</p>