Finding Pink Discoloration (“Pink Panther”) Among “Panther Patches” On Esophageal Iodine Stain Leads to Detection of Early Esophageal Cancer

Abstract

Aim: Esophageal cancer is common in patients with a history of head and neck cancer and/or patients with a habit of drinking and smoking. Early detection of esophageal cancer enables endoscopic therapy of the cancer. However, it is often difficult to detect early esophageal cancer on conventional endoscopic observation. Iodine stain of the esophageal mucosa has been developed to detect cancer based on the difference of stainability with iodine between normal esophageal mucosa and cancer. Normal esophageal mucosa contains abundant glycogen, which is stained dark-brown with iodine. Thus areas unstained with iodine have a good chance to be a cancer. But some patients present with multiple and diffuse unstained areas on iodine stain (Panther patches). It is not practical in these patients to perform histological evaluation on every unstained area. We noticed that some unstained areas on iodine stain appeared pink during the period when the dark brown color gradually faded. An aim of this study is to evaluate the predictability of this area to be a cancer. Patients & Methods: We reviewed retrospectively upper GI endoscopy records of the Cancer Institute Hospital for the recent 21 months. Out of 15,000 patients who underwent upper GI endoscopy, 1,975 were examined for esophagus in detail using 1.5% iodine solution to detect esophageal cancer. Results: Esophageal mucosa stained with iodine showed “Panther patches” in 125 patients. Among them, pink discoloration (Pink panther) was visible in 20 patients during the period when dark-brown stain gradually fading. Histological evaluation of those 20 patients revealed that 12 (60%) had squamous cell carcinoma, 7 (35%) had dysplasia, and 1 (5%) had inflammation. Discussion: Iodine stain is a good method to detect early esophageal cancer. However, a number of patients present with multiple unstained areas on iodine stain. Pink discoloration may reflect the increased blood flow of the cancer. Conclusion: Finding a pink panther among panther patches on esophageal iodine stain leads to detection of early esophageal cancer.