Atypical Appearance on Radioiodine Scintigraphy Due to Achalasia Cardia - A Potential Diagnostic Pitfall

We present the case of a 36-year-old woman with papillary thyroid cancer (PTC) who had undergone thyroidectomy and nodal dissection. In addition to thyroid remnant and nodal metastases, initial postoperative radioiodine (RAI) diagnostic whole-body scintigraphy showed abnormal diffusely increased linear band-like uptake in the thorax corresponding to the esophageal contour, raising suspicion of lower esophageal obstruction. Retrospective inquiry revealed a history of long-standing, progressive dysphagia. Findings of computed tomography, barium swallow study, and esophageal manometry were consistent with achalasia cardia. She underwent high-dose RAI therapy for PTC and laparoscopic cardio-myotomy for achalasia cardia. This case report aims to familiarize nuclear medicine physicians with the appearance of achalasia cardia on RAI scintigraphy, which may mask surrounding lymph nodal or vertebral metastases. Such a finding when encountered should also prompt further work-up and appropriate management.