Leprosy is a spectral disease. Its two polar forms, tuberculoid (TT) and
lepromatous (LL), are distinct presentations of the disease, both from a clinical and
histopathological/bacilloscopic point of view. In this chapter, the histopathological
characteristics that define the two polar forms (TT and LL) are presented, and their
main differential diagnoses are discussed. These two forms also have significant
differences in their treatment protocol. Histopathological recognition of both forms of
the disease is important for choosing the correct treatment. Also, there are a large
number of diseases that can have a clinical presentation similar to the TT and LL forms
of leprosy. In this context, histopathological examination is essential for defining the
diagnosis of leprosy.
Keywords: Hansen's disease, Lepromatous leprosy (LL), Leprosy, Mycobacterium leprae, Tuberculoid leprosy (TT).
