Serendipitous discovery in a fistula-in-ano

A woman in her early 30s presented with perianal purulent discharge. A rectal examination showed a high complex fistula-in-ano. A fistulotomy was performed wherein two fistulous tracts at the 4 o’clock and 8 o’clock position involving the external sphincter muscle were identified, and the granulation tissue was submitted for histopathological evaluation. 1. A dense infiltrate of macrophages with an artefact amidst the granulation tissue. 2. Macrophages exhibiting emperipolesis along with a cotton fibre adjacent to them. 3. Macrophages exhibiting emperipolesis along with a parasite in the adjacent tissues. 4. Macrophages exhibiting emperipolesis with a slender vegetable cell adjacent to them. Amidst abundant granulation tissue, without eosinophils, were numerous multinucleated macrophages showing emperipolesis (figure 1). The engulfed cells were lymphocytes, plasma cells and occasional …