Table 1.
Features of skin lesions that emerged after completion of antibiotic treatment.
Figure 1.
Clinical presentation of lesions (Patient 1).
A: Initial ulcerated lesion at the right arm, reaching from the elbow to the forearm. B: Nodule1 appearing on the back, 275 days after end of antibiotic treatment. Both, nodule 2 on the thorax (C) and an ulcerated plaque on the right shoulder (D) had appeared 409 days after completion of antibiotic treatment.
Figure 2.
Histopathological presentation of secondary lesions.
Histological sections (nodule 2 of patient 2) were stained either with Ziehl-Neelsen (counterstain methylenblue; A, F, G) or with antibodies against cell surface or cytoplasmic markers (counterstain haematoxylin; B–E). A: Overview over excised tissue specimen revealing typical BU pathology features like fat cell ghosts, necrosis, epidermal hyperplasia and AFB (region 2) as well as a strong mixed infiltration typically observed in successfully treated BU lesions (region 1). B: CD14 staining of macrophages/monocytes; C: CD3 staining of T-cells; D: Elastase staining of neutrophils. In the necrotic region 2 large numbers of elastase-positive neutrophilic debris (E) and small clumps of AFB (F) with a beaded appearance (G) were observed.
Figure 3.
Presence of B-cell clusters in the secondary lesions.
A: Band of CD20 positive B-cells in sections of ulcer 2 of patient 1. B–E: serial sections of nodule 3 of patient 2 with a small dense cluster of CD20 positive B-cells (B) surrounded by CD14 positive macrophages/monocytes (C) and few interspersed CD3 positive T-cells (D) from which the majority was CD8 negative (E). Higher magnification (F–I) revealed a very dense package of the B-cells.
Figure 4.
Bands of leucocytes surrounding an uninfiltrated necrotic area.
Serial sections of nodule 2 of patient 1 with a necrotic area surrounded by a belt of CD14 positive monocytes/macrophages (A) and a more external second belt of CD3 positive T-cells (B). The necrotic core contained N-elastase positive neutrophilic debris (C), but no intact neutrophils (D insert). Clusters of CD20 positive B-cells were found away from the necrotic core (D).