Multiple ectopic goiter in the retroperitoneum, abdominal wall, liver, and diaphragm: A case report and review of literature

BACKGROUND Ectopic thyroid is a rare developmental disorder, typically found in lingual areas, and most distantly in the abdomen. Thyroid ectopia in multiple regions is extremely rare. To date, there are no reports of ectopic goiter in four regions of the abdominal cavity in a single patient. CASE SUMMARY We present a case of thyroid ectopia in four areas of the abdomen, comprising normal orthotopic thyroid tissue. A 36-year-old woman, who underwent ovarian teratoma resection 10 years previously due to symptomatic ovarian teratoma, was referred to our hospital for treatment of an incidental hepatic mass. Magnetic resonance imaging and computed tomography (CT) of the abdomen showed a heterogeneously enhanced lobulated lesion in the sixth and seventh hepatic segment adjacent to the diaphragm. The mass was surgically excised, and histologic examination determined an ectopic nodular goiter. At the one-year follow-up, the abdominal CT scan, whole-body radionuclide I131 examination, and abdominal wall biopsy showed similar lesions in the left renal fascia and anterior abdominal wall. CONCLUSION Multiple para-ectopic thyroid is often misdiagnosed, owing to its extremely rare incidence and non-specific clinical manifestations and imaging features. A combination of multiple examinations is necessary for diagnostic accuracy.