Ambiguities in leprosy histopathology

Area of Science:

• Dermatology
• Pathology
• Infectious Diseases

Background:

• Leprosy diagnosis relies on histopathological examination of skin biopsies.
• Histological criteria for leprosy include the presence of acid-fast bacilli (AFB) and nerve involvement, alongside suggestive signs like granulomatous inflammation.

Purpose of the Study:

• To evaluate the diagnostic yield of histopathological criteria in leprosy biopsies.
• To assess the prevalence of definite and suggestive leprosy signs in a large cohort.
• To propose standardized terminology for leprosy histopathological reporting.

Main Methods:

• Retrospective analysis of 482 leprosy biopsies.
• Classification of cases into definite, suggestive, or no leprosy based on predefined histopathological features.
• Evaluation of AFB presence, nerve involvement, and inflammatory cell infiltration.

Main Results:

• Definite signs of leprosy were identified in 72.2% of biopsies.
• Suggestive signs were present in 14.1% of biopsies.
• 13.7% of cases showed no definitive or suggestive signs, often representing healed lesions.

Conclusions:

• Histopathology is crucial for leprosy diagnosis, with a high percentage of cases showing diagnostic features.
• Healed lesions and granulomas lacking nerve elements pose diagnostic challenges.
• Standardizing terminology to "definite," "suggestive," or "no diagnosis" is essential for consistent reporting.