Heterotopic ossification of the esophagus identified during surgical management of esophageal carcinoma.

Heterotopic ossification (HO) is the formation of mature lamellar bone within soft tissues and is most commonly associated with trauma or neurologic injury. Gastrointestinal involvement is exceedingly rare, with only one prior reported case of esophageal HO in association with Barrett's esophagus. The pathogenesis remains poorly understood but is thought to involve chronic inflammation and dysregulated mesenchymal cell differentiation. We report a rare case of heterotopic ossification of the esophagus identified during the diagnostic evaluation and surgical management of esophageal squamous cell carcinoma following neoadjuvant chemoradiation. Intraoperatively, a firm, foreign body-like structure was encountered at the tumor site and was histologically confirmed as mature heterotopic bone without residual carcinoma. This represents the second reported case of esophageal HO and the first described in association with malignancy. Recognition of this entity is important, as heterotopic bone may complicate surgical dissection and mimic malignant invasion, with potential implications for staging and operative planning.