PMC5482912_01
Coronal pelvic magnetic resonance image before antibiotic therapy, depicting a short, trans-sphincteric component of the complex perianal fistula dividing in the ischioanal space (arrow), with significant densification of surrounding fat (arrowhead).
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F1
Pelvic magnetic resonance imaging 1 month after hospital discharge revealed multiple fistulous tracts, including trans-sphincteric and suprasphincteric tracts and a rectovaginal fistula (Figure 1).
Photograph showing several setons in situ, the most anterior corresponding to the rectovaginal tract (arrowhead). The most posterior external orifice shows significant granulation tissue (white arrow). A scar from abscess drainage is visible close to the left labium majus (black arrow).
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F2
In the following 3 years, the patient underwent multiple abscess drainages, fistulae treatment by seton placement, and empiric antibiotic courses, with no overall improvement (Figure 2).
Anal cytology (papanicolau stain, 40x) identified filamentous bacteria compatible with Actinomyces species (arrow).
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F3
In 2016, repeated anal cytology revealed the presence of bacterial colonies compatible with Actinomyces spp. (Figure 3).
Perianal examination showing significant improvement of the perianal fistulae after removal of setons, with most orifices being closed, no signs of new fistulous tracts, and no exudation. The fistulous tract involving the vagina is still visible, but with no exudation (arrowhead). The anal sphincter complex has preserved morphology and tonus (arrow).
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F4
This resulted in a remarkable clinical improvement, allowing for the removal of setons (Figure 4).
Coronal pelvic magnetic resonance image after 5 weeks of penicillin, showing almost complete resolution of the fistulous tracts (arrows).
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F5
The reevaluation magnetic resonance imaging, performed after only 5 weeks of antibiotic therapy, showed almost complete resolution of the fistulous tracts (Figure 5).