Track

Clinical Studies

Abstract

In dermatopathology, special stains are often necessary to identify the culprit organism when infection is suspected. Historically, mycobacterium have been detected using acid fast techniques. While the Ziehl-Neelsen technique was first favored, the Fite-Faraco has now become the standard. Interestingly, one case reported that immunohistochemistry (IHC) for Treponema pallidum was positive in a later confirmed case of Mycobacterium leprae. This implies cross reactivity of the spirochete IHC for M. leprae. This study evaluates the staining pattern of mycobacterial infections with spirochete ICH.

A retrospective search of a dermatopathology database (2000–2025) identified cases of mycobacterial infection including: 10 cases of leprosy, 3 cases of tuberculosis, and 2 cases of other mycobacterial infections. Clinical impression, special stains used, and histopathologic diagnosis of each case were recorded. Each case will be tested with spirochete stain and pattern will be recorded.    

We expect to describe 10 cases of leprosy identified by spirochete IHC. We also expect to demonstrate that the spirochete IHC does not highlight other mycobacteria, suggesting that it is be specific for M. leprae. In this context, spirochete IHC could function as a surrogate marker, analogous to p16 immunostaining as an indicator of high-risk HPV–associated squamous cell carcinoma. This ICH would be useful in the confirmation of the diagnosis when leprosy is clinically suspected, especially due to the inability to culture M. leprae in vitro, limited availability of M. leprae culture in vivo, and slow growing nature of the organism.