Research papersTypical MR imaging findings of perianal infections in patients with hematologic malignancies

- Perianal infections can be the cause of sepsis in patients with neutropenia. Clinical manifestation may be modified by immunocompromise.
- As rectal examination is usually avoided in these patients MRI gains importance and can demonstrate almost all forms of anorectal infections.
- Patients with hematological malignancies may have significant perianal edema but may rarely have defined fistula tracts on MR images.
- Rather than an ordinary fistula formation the infected tissue may have no clear boundaries or a distinct course.
- Radiologists must pay attention to the whole field of view in order not to overlook perineal and labial abscesses

ObjectiveWe aimed to investigate the MR imaging findings of patients with hematologic malignancies who have symptoms suggesting perianal infection and to demonstrate the importance of imaging.Subjects and methodsThe study included 36 patients with hematologic malignancies who underwent anorectal MR imaging in our department between September 2011-May 2016. Two radiologists experienced in abdominal radiology viewed the MR images in consensus. Abscesses, fistulous or sinus tracts, signal alterations and contrast enhancement in keeping with an inflammation and edema in the perianal region were recorded.ResultsPerianal abscess was found in 16 of the 36 patients. In 10 of these 16 patients there was also extensive inflammatory signal alterations in perianal and/or perineal soft tissues.In six of the 36 patients perianal fistula was detected. A sinus tract was seen at the level of subcutaneous external anal sphincter in one patient. Inflammatory signal alterations in the surrounding soft tissues were present in three of these seven patients.There were abscesses in labium majus in two patients and in one patient there were perineal abscesses with accompanying inflammatory signal alterations.In six of the 36 patients no abscess or fistula/sinus tract was seen. There were only inflammatory signal alterations with contrast enhancement in perianal or subcutaneous tissues.In two patients presenting with perianal pain and hemorrhoids, minimal inflammatory changes were detected on MR images.There were two patients with normal MR imaging findings.ConclusionAs digital examination of the anorectum and rectoscopy are avoided in neutropenic patients, MR imaging, which clearly demonstrates the perianal pathology should be preferential.