A case series of dermatofibromas originating in leprosy lesions: a potentially misdiagnosed condition

DFs originating in leprosy lesions were considered when the histological sections clearly showed the DF inserted in the context of a leprosy lesion in regression in the adjacent tissues. Clinical data (sex, age, location of DF, classification of leprosy and leprosy reactions, time between the leprosy and DF diagnoses, and treatment of leprosy reactions) were retrieved through the review of medical records. Fig. 1 Representative panel of dermatofibroma originating in a leprosy lesion: a, c, e, and g Hematoxylin-eosin-stained histological section showing the dermatofibroma in the center (light arrows) and the leprosy lesion in regression at the periphery (dark arrows); b, d, f, and h histological section for bacilloscopy (Fite-Faraco) showing absence of bacilli in the dermatofibroma (clear arrows) and presence of fragmented bacilli in the leprosy lesion in peripheral regression (dark arrows); i, j, k, l basic immunohistochemical panel – expression of anti-CD68 (i) in leprosy lesion macrophages and the absence of anti-factor XIIIa expression in the same macrophages (j); the absence of anti-CD68 expression (k) and the expression of anti-factor XIIIa in dermatofibroma cells Numeric variables are described as the mean (SD) or median (interquartile range) according to the normality of their distribution, and categorical data are described as the frequency/percentage. Body location of DF Leprosy patients with DF, count (%) Non-leprosy patients with DF, count (%) Total Cervical 0 (0%) 1 (0.5%) 1 Face 0 (0%) 2 (1.0%) 2 Thorax 0 (0%) 9 (4.7%) 9 Abdomen 0 (0%) 1 (0.5%) 1 Dorsum 4 (13.3%) 27 (14.1%) 31 Thigh 10 (33.3%) 35 (18.2%) 45 Arm 7 (23.3%) 31 (16.1%) 38 Hand 1 (3.3%) 5 (2.6%) 6 Buttock 1 (3.3%) 1 (0.5%) 2 Knee 2 (6.7%) 2 (1.0%) 4 Forearm 1 (3.3%) 21 (10.9%) 22 Leg 9 (30.0%) 54 (28.1%) 63 Elbow 1 (3.3%) 9 (4.7%) 10 Shoulder 0 (0%) 5 (2.6%) 5 Foot 1 (3.3%) 4 (2.1%) 5 Perineum 0 (0%) 1 (0.5%) 1 Total 30 192 222 All DFs in RLLs were common DFs, and three of them had the histologic patterns characteristic of the atrophic variant.