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OpenAthens Shibboleth
Special Feature
October 20, 2008

Image of the Month—Quiz Case

Author Affiliations

Author Affiliations:Departments of Pathology (Dr Huang) and Radiology (Dr Dobos) and Division of Surgical Oncology (Dr Billingsley), Oregon Health and Science University (Dr Mayo), Portland. Dr Mayo is currently a resident in general surgery at The Johns Hopkins Hospital, Baltimore, Maryland.




Copyright 2008 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2008

Arch Surg. 2008;143(10):1017. doi:10.1001/archsurg.143.10.1017

A 43-year-old man was referred to our institution with lower abdominal pain and perineal swelling and fullness of more than a year. At the referring hospital, he underwent a nondiagnostic computed tomography–guided biopsy of what was presumed to be a large pilonidal cyst. His medical history was unremarkable for hematochezia or alteration in bowel function. Magnetic resonance imaging at our institution revealed a 14 × 10.5 × 25-cm bilobed, cystic mass situated in his pelvic outlet in the retrorectal space, markedly compressing his rectum (Figure 1and Figure 2). There was a suggestion of internal hemorrhagic vs proteinaceous debris with degenerative changes within the mass and enhancing mural nodules. The mass extended through the floor of the pelvis and into the perineal area. It did not appear to invade his rectum or involve the regional vasculature.

Figure 1.
Image not available

A sagittal T2-weighted magnetic resonance image demonstrates the bilobed retrorectal mass compressing the adjacent structures. The arrow indicates the compressed rectum, and the asterisk indicates the bladder.

Figure 2.
Image not available

A coronal digital subtraction magnetic resonance image demonstrates multiple enhancing mural nodules on the mass indicated by the arrow.

What Is the Diagnosis?

A. Enteric duplication cyst

B. Complex pilonidal cyst

C. Retrorectal cystic hamartoma (tailgut cyst)

D. Perirectal abscess