Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
Esophageal tumors are considered a rarity in present day diagnostic interpretations, however, a report from Alabama indicates that such tumors are by no means so rare as have been the indications. In a series of esophageal neoplasms found in dogs over a period of 3 years the esophageal worm, Spirocerca lupi, was found in each tumor. This may possibly indicate the etiological importance of the parasite.
Kenagy, C. Oliver
"Esophageal Tumor in a Dog,"
Iowa State University Veterinarian: Vol. 20
, Article 9.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol20/iss3/9