This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
The malignancy which is a close mimicker of achalasia is: 
Select and explain. 
A. Carcinoma of the gastric fundus, B. Middle esophagus carcinoma, C. Carcinoma larynx, D. Thyroid malignancy
A: Carcinoma of the gastric fundus
Answer: A: Carcinoma of the gastric fundus 
Explanation: The differential diagnosis of achalasia are DES Chagas' disease Pseudoachalasia Chagas' disease is spread by the bite of the reduvid (kissing) bug that transmits the protozoan, Trypanosoma cruzi. Tumor infiltration, most commonly seen with carcinoma in the gastric fundus or distal esophagus can mimic idiopathic achalasia and known as"pseudoachalasia". Nearly 5 % cases of suspected achalasia are pseudoachalasia. Ref: Harrison, Edition-18, Page-2431