Histological grading patterns in patients of cutaneous leishmaniasis.

OBJECTIVE: To determine the histological grading patterns in a cohort of hospitalized patients of cutaneous leishmaniasis. DESIGN: Case series. PLACE AND DURATION OF STUDY: The study was conducted at PNS Shifa Hospital, Karachi, from May 2004 to June 2006. PATIENTS AND METHODS: One hundred patients of Cutaneous Leishmaniasis (CL), admitted in dermatology wards at PNS Shifa Hospital, Karachi, were examined. Only admitted patients of all ages and both sexes were included in the study. Patients of CL, who had received or were receiving systemic treatment were excluded. The lesions having marked secondary bacterial infection were also excluded. Initial diagnosis was clinical. History of being to an endemic area supported the diagnosis. The lesions were divided in two groups. Early, with duration less than 03 months and late, with duration between 3 and 12 months. The clinical lesions were noted as nodules, plaques, ulcers, crusted ulcers, lupoid lesions and plaques with scarring. Three types of skin smears (slit skin smear, saline aspirate smear and dab smear) were taken and examined with Giemsa stain. Cultures were performed on Nicolle-Novy-MacNeal (NNN) culture medium from Defense Scientific and Technology Organization (DESTO) Lab., Pakistan. Incisional skin biopsies were done. The biopsy specimens were examined by hemotoxylin and eosin stain (H & E stain). The number of Leishmania Tropica (LT) bodies was graded according to modified Ridley's parasitic index 1983. Clinical features were correlated with the histological patterns. RESULTS: Five histological patterns were identified in current study: 1) diffuse dermal infiltration without necrosis, 2) patchy dermal infiltration, 3) diffuse dermal infiltration with necrosis, 4) early reactive granuloma formation and 5) established epithelioid granuloma formation. LT bodies were identified in 75% of cases. Epidermal features were non-specific. The early lesions presented with diffuse infiltrate and late lesions showed granuloma formation. CONCLUSION: Five distinct types of histological patterns of CL have been recognized in this study. The early lesions presented with diffuse infiltrate and late lesions showed granuloma formation but the mixed patterns were also seen. The yield of LT bodies is much higher with histopathology as compared to skin smears and hence is most diagnostic.