Giant cells lepromatous leprosy. Diffuse dermatitis with exuberant foreign body giant cells in treated lepromatous leprosy

Abstract

Patients with lepromatous leprosy (LL) that have received treatment for many years, usually get follow up biopsies for persistent skin lesions or positive bacilloscopy, even with lower values than in the initial bacilloscopy. Here, we report a case of a 48-year old woman with long-standing LL of 15 years of evolution, with a bacterial index (BI) of 4 in the direct smear and in the initial skin biopsy. The patient was treated with multidrug therapy (MDT) for 32 months although the treatment recommended by de World Health Organization (WHO) is only for 12 months. A skin biopsy was taken to determine if there was active disease. A diffuse dermal inflammation with numerous foreign body giant cells and vacuolated macrophages (Virchow's cells) was observed. These cells contained granular acid-fast material that was also positive with immunohistochemistry (IHC) for BCG. There were fragmented bacilli and the BI was 2. These cells were also strongly positive for CD68. The biopsy was interpreted as a residual form of LL that did not require further MDT. We have observed similar histological profiles in several cases. Lack of clinical data makes it a histological challenge. Accumulation of lipids in these giant cells is due to bacillary destruction and fusion of vacuolated macrophages. The role of bacillary and host lipids in the pathogenesis of lepromatous leprosy is discussed. There is no need to extend the 12-month MDT recommended by the WHO. Clinical findings, bacilloscopy, annual skin biopsy, and anti-phenolic glycolipid-I IgM titles are recommended procedures for follow-up of these patients. © 2019 Instituto Nacional de Salud.