Since Laennec's description of the "prosector's wart" in 1826, science has made great strides forward. The cutaneous forms of the infection with Mycobacterium tuberculosis are various. The most common clinical forms of cutaneous tuberculosis are lupus vulgaris and scrofuloderma. The clinical forms of cutaneous tuberculosis are usually classified according to the patient's immune status, and the way through which the skin has been infected. Nonetheless, as in leprosy, a classification based on the importance of the bacterial inoculum in situ is possible. Subsequently the diagnosis should be considered as easy in the multibacillary forms and much more difficult in the paucibacillary forms. In the former, the diagnosis should rely on bacteriological data. In the latter, the diagnosis will rely on the association of epidemiological, clinical and histological data whereas genomic amplification with PCR may be of potential interest.