Clinically unsuspected neuritic leprosy with caseation necrosis.

Leprosy is a devastating disease caused by Mycobacterium leprae. It includes a spectrum of clinicopathological lesions. Neuritic leprosy with caseation necrosis (abscess) manifesting as a soft tissue mass is a relatively rare presentation of leprosy. Here, the authors report their experience with three patients with neuritic leprosy. The patients presented with swellings in the right ulnar nerve, the right great auricular nerve, and the temporal branch of the right sixth cranial nerve. The clinical impression was that of tumorous masses. Gross examination of the biopsy specimens revealed caseous necrotic materials. Further histological evaluation disclosed tuberculoid granulomas with extensive caseation necrosis. Stains for acid-fast bacilli were positive in the third case. A comparison between the caseation encountered in the tuberculoid neurotic leprosy and the neurolysis of lepromatous neurotic leprosy has been also discussed. The findings here emphasize "mass lesion with necrosis" as a possible clinical presentation of the neuritic leprosies. The clinicopathologic features were addressed and the relevant literature was reviewed.