Incidental Detection of Situs Inversus Totalis During Preoperative Evaluation for Thyroid Cancer: A Case Report.

Situs inversus totalis (SIT) is an uncommon congenital condition in which the thoracic and abdominal organs are arranged in a mirror-image orientation. While often asymptomatic, undiagnosed SIT can complicate clinical evaluation, imaging interpretation, and surgical planning. We present the case of a 60-year-old woman with a palpable neck mass diagnosed as papillary thyroid carcinoma. During the preoperative assessment, a physical examination revealed right-sided heart sounds, and an electrocardiogram showed a right axis deviation with inverted P waves. Chest radiography and abdominal imaging confirmed complete thoracoabdominal organ reversal consistent with SIT, without associated cardiac anomalies. The patient underwent a successful total thyroidectomy with no intraoperative complications. Histopathology revealed multifocal disease with capsular invasion. Postoperative recovery was uneventful, and follow-up care included thyroid hormone replacement and surveillance imaging. This case highlights the rare coexistence of SIT and papillary thyroid carcinoma, underscoring the importance of recognizing SIT in surgical and anesthetic planning. Routine preoperative imaging plays a critical role in identifying anatomic variants, preventing misinterpretation of clinical findings, and minimizing perioperative risk. While no causal link between SIT and thyroid carcinoma can be inferred from a single case, the report adds to the very limited literature and emphasizes the need for vigilance in both diagnostic evaluation and operative management of patients with SIT.