Ambiguities in leprosy histopathology.

This paper presents the percentage of definite or suggestive evidence present in 482 biopsies from different types of leprosy. The presence of acid-fast bacilli (AFB) and nerve involvement were taken as definite features for a diagnosis of leprosy, and infiltration of the dermal appendages, neurovascular bundles and dermis by granuloma cells and lymphocytes were regarded as suggestive signs of leprosy. Using these criteria, all cases were categorized into three groups having definite, suggestive, or no signs of leprosy. The results showed definite and suggestive features in 72.2% and 14.1% of the cases, respectively. The remaining 13.7% had none of these signs. These cases were mostly healed lesions. Large, epithelioid cell granulomas without any nerve element present and healed cases proved difficult for a definite diagnosis. Emphasis is placed on searching for residual nerve elements in AFB-negative sections because this increases the certainty level of the diagnosis. Also, it is suggested that for uniformity of understanding and reporting, terminologies need to be narrowed down and restricted to only definite, suggestive, or no diagnosis of leprosy.