For five years he continued work in its surgical department with Professor Hauari Miyake and in 1912 wrote his M.D. thesis on his discovery "Struma lymphomatosa," a goiter or enlargement of the thyroid associated with hypothyroidism. This case report described the four histological characteristics of the disease; diffuse lympohcytic infiltration, formation of lymphoid follicles, destruction of epithelial cells and proliferation of fibrous tissue. Because his paper was published in a German surgical journal, his countrymen were unaware of this work. Hashimoto spent the next 3 years in Berlin, Gottingen and London concentrating on renal tuberculosis.
The outbreak of World War I and the coincidental death of his father
brought him back to Japan and into the family practice. Dr. Hashimoto
was a fervent Buddhist and was fond of Japanese theater. He became
a prosperous surgeon earning the high regard of his colleagues, especially
in major abdominal surgery. Two other papers completed his published
work, one on the skin infection erysipelas or St. Anthony's Fire, and one
on penetrating wounds of the chest. Hakaru Hashimoto died of typhoid
in 1934 at the age of 53.