Leprosy Neuropathy in a Non-Endemic Area: A Clinical and Pathological Study

The extent of nerve involvement in leprosy is highly variable in distribution and clinical presentation. Mononeuropathies, multiple mononeuropathies, and polyneuropathies can present both in the context of a cutaneous and/or systemic picture and in the form of pure neuritic leprosy (PNL). The differential diagnosis of leprosy neuropathy remains challenging because it is a very rare condition and, especially in Western countries, is often overlooked. We report one case of the polyneuropathic form of PNL (P-PNL) and one case of multiple mononeuropathy in paucibacillary leprosy. In both cases, the diagnosis was achieved by performing a sural nerve biopsy, which showed subverted structure, severe infiltration of inflammatory cells in nerve fascicles, granulomatous abnormalities, and the presence of alcohol-acid-resistant, Ziehl-Neelsen-positive bacilli inside the nerve bundles. Leprosy remains an endemic disease in many areas of the world, and globalization has led to the spread of cases in previously disease-free countries. In this perspective, our report emphasizes that the diagnostic possibility of leprosy neuropathy should always be taken into account, even in Western countries, in the differential diagnostic process of an acquired sensory polyneuropathy or multineuropathy and confirms that nerve biopsy remains a useful procedure in working up neuropathies with unknown etiology.