PMC6768825_01
Physical and radiologic images.. (a) Physical examination shows a small, accessory opening (arrow head), located at midline, approximately 1 cm posterior to the true anus (arrow).. (b) Fistulography shows a 2-cm canal (arrow head) without connecting with the rectum (arrow).. (c) Endoanal ultrasonography shows a brightly hyperechoic blind-ending fistulous tract (arrow head) and a hypoechoic cystic mass (arrow) in the superior retrorectal area.. (d) Magnetic resonance imaging shows a multiloculated presacral cyst (arrow head) posterior to the rectum.
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The orifice was located at midline, approximately 1 cm posterior to the true anus (Figure 1a). Fistulography revealed a 2-cm-long narrow canal without connection with the rectum (Figure 1b). Endoanal ultrasonography (EAUS) with hydrogen peroxide injection revealed a brightly hyperechoic, blind-ending fistulous tract and a hypoechoic cystic mass in the superior retrorectal area (Figure 1c). Magnetic resonance imaging (MRI) revealed a multiloculated presacral cyst posterior to the rectum (Figure 1d).
Intraoperative images.. (a) The lesion circumscribing the second anal orifice (arrow head) was removed with incision, and the fistulous tract was carefully separated from the external anal sphincter.. (b) The fistulous tract was found to be tubular, 2-cm long (arrow head), and connected with the superior presacral cyst (arrow).. (c) The resected specimen shows the distal portion is a 2.0-cm-long duct (arrow head) and is superiorly connected, via the firm restiform tissue, with a 5.0x5.0x2.0-cm cyst (arrow), filled with sebaceous material.
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The lesion circumscribing the second anal orifice was removed with incision, and the fistulous tract was separated carefully from the external anal sphincter and part of the striated muscle complex (Figure 2a). The fistulous tract was tubular, 2-cm long, and connected to the superior presacral cyst (Figure 2b). The resected specimen showed a distal, 2.0-cm-long duct superiorly connected via firm restiform tissue with a 5.0 x 5.0 x 2.0-cm cyst filled with sebaceous material (Figure 2c).
(a) The duct is predominantly lined by squamous epithelium (arrow head) and the cyst is lined by squamous, columnar, and transitional epithelia (arrow). (hematoxylin-eosin stain, 40x).. (b) Smooth muscle bundles are present in the wall of the duct (arrow head). (hematoxylin-eosin stain, 40x).
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Histologic examination revealed that the duct was predominantly lined by squamous epithelium and that the cyst was lined by squamous, columnar, and transitional epithelia (Figure 3a). Smooth muscle bundles were present throughout the duct wall (Figure 3b).