The study of histologic changes in leprosy antedates by approximately a generation the discovery of Mycobacterium leprae by G. Armauer Hansen. The history of the histopathology of leprosy suggests two distinct periods. The first began in 1847 with Danielssen's and Boeck's illustration of a section of a nodule, and continued into the 1920's. It was a period of observation and record, and was followed by a later phase in which histologic studies entered into modern classification of types of leprosy. This has been an interpretive period, contributing importantly to modern concepts of the mechanisms of the disease.
Fite GL, Mansfield RE. The Role of Histology in the Study of Leprosy. Arch Dermatol. 1969;100(4):478-483. doi:10.1001/archderm.1969.01610280096019