|Year : 2022 | Volume
| Issue : 1 | Page : 120-124
Presacral epidermoid: A rare case and meningocele mimick
Department of Neurosurgery, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India
|Date of Submission||23-Sep-2020|
|Date of Decision||12-May-2021|
|Date of Acceptance||09-Jun-2021|
|Date of Web Publication||02-Feb-2022|
Department of Neurosurgery, Indraprastha Apollo Hospital, Sarita Vihar, Mathura Road, New Delhi 110076.
Source of Support: None, Conflict of Interest: None
Epidermoid cysts of the presacral space are a rare congenital entity. They have mostly been reported among women. We report a case of a 28-year-old male presenting with chronic constipation wherein magnetic resonance imaging (MRI) was suggestive of an anterior sacral meningocele associated with an epidermoid. This patient underwent a laparotomy and total excision of the mass. The lesion turned out to be an epidermoid cyst without any intradural communication or associated meningocele. This report highlights the limitations of imaging while it accentuates the need to perform diffusion-weighted MRI sequences for all cystic tumors in this region and to choose the correct operative approach based on its exact location in the presacral space.
Keywords: Diffusion-weighted sequence, epidermoid, meningocele, presacral
|How to cite this article:|
Mediratta S. Presacral epidermoid: A rare case and meningocele mimick. Indian Spine J 2022;5:120-4
| Introduction|| |
Presacral tumors or retrorectal masses are not frequently encountered entities. Epidermoid cysts are congenital tumors of ectodermal origin and rarely seen in the presacral space, with most cases reported among women of child-bearing age., There have only been three case reports of presacral epidermoid tumors involving males., This case report is of a young male with a rare presacral epidermoid tumor who presented with non-specific perianal discomfort associated with constipation. Preoperatively, he was suspected to have a large anterior sacral meningocele associated with an epidermoid.
| Case Report|| |
A 28-year-old male presented with complaints of vague discomfort around the perineal region and straining to pass stools of six months duration and had been on laxatives for over one month. There was no history of pain, fever, trauma, bleeding per rectum, loss of weight, difficulty in passing urine, or loss of perianal sensation. On examination, his motor power was 5/5 in bilateral upper and lower limbs along with normal deep tendon reflexes. Anal tone was normal with bilateral decreased perianal sensation. A plain lumbar spine magnetic resonance imaging (MRI) revealed a large tumor in the presacral region which was hypointense on T1-weighted (wt) image and homogeneously hyperintense on T2-wt image and showed communication with the dural sac [Figure 1] and [Figure 2]. On diffusion-weighted image (DWI), the lesion showed restricted diffusion and appeared hyperintense [Figure 3]. A differential diagnosis of meningocele or an epidermoid within a meningocele was considered.
|Figure 1: MRI lumbar spine. T1-wt sagittal image showing a large homogeneously hypointense lesion in the presacral region with a low-lying cord at L3. There is partial agenesis of S2 with complete agenesis of the sacrococcygeal segments below it|
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|Figure 2: MRI lumbar spine. T2-wt sagittal image showing a well-defined hyperintense presacral lesion in communication with the dural sac (arrow)|
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|Figure 3: MRI pelvis. DWI (left) and ADC sequence (right). Lesion shows diffusion restriction and appears hyperintense on DWI|
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Also seen was a low-lying spinal cord at L3 and partial sacral agenesis of S2 with complete agenesis of the sacrococcygeal segments below it [Figure 1].
A pelvic MRI with contrast study was performed for detailed anatomic outline of the lesion prior to planning the surgery. The tumor was visualized as hypointense on T1-wt image [Figure 4] and hyperintense on T2-wt images and showed poor contrast enhancement [Figure 5]. The rectum was seen compressed by the mass. Based on the pelvic MRI, an anterior surgical approach was decided for complete excision of the lesion. The patient underwent a midline laparotomy and total excision of the lesion en mass. The lesion was a well-defined, reddish, encapsulated, fibrous mass containing white flaky material of toothpaste-like consistency [Figure 6]A and B.
|Figure 4: MRI pelvis. T1-wt axial view shows the hypointense tumor (arrow)|
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|Figure 5: MRI pelvis. Post-contrast T1-wt sagittal images show mild enhancement of the tumor wall and communication with the thecal sac (arrow)|
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|Figure 6: (A) Gross appearance of the encapsulated specimen (red) with some keratinous contents (white) lying on its wall. (B) Encapsulated tumor with its keratinous and toothpaste-like contents brought out|
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There was a well-defined plane between the mass and the rectal wall, iliac vessels, and the ureter; however, there was significant blood loss while dissecting the posterior wall of the tumor from the presacral fascia. The bleeding from the presacral venous plexus was controlled by packing the posterior wall with abdominal mops. The total blood loss was about 800 mL. No communication with the dural sac was encountered, nor was any cerebrospinal fluid (CSF) leak seen intraoperatively after completion of the resection. For up to 2 weeks after the surgery, the patient had paraesthesias around the left perianal and gluteal region, which gradually subsided spontaneously. He had recovered well and was able to pass urine and stools comfortably before discharge from the hospital. He has been doing well for the past 6 months and has been off laxatives.
| Discussion|| |
Tumors are rarely found to develop in the presacral or the retrorectal space.,, This is a potential space in front of the presacral fascia and behind the mesorectal fascia, bounded laterally by the iliac vessels and ureter. The superior and inferior limits of this space are defined by the peritoneal folds and the levator ani muscle, respectively.,, Most often reported tumors in this region are usually benign and congenital in origin.,
An epidermoid cyst developing in this area is rare and has been more often reported in women of reproductive age group,, with only three cases reported in men.,
Owing to their location and slow growth, these tumors can remain asymptomatic, or discovered as incidental findings., Pain and constipation are the commonest presenting features as was seen in this case as well. MRI along with its DWIs is considered to be the preferred imaging of choice for presacral tumors as it allows for a better soft tissue delineation.,,, The cyst appears as hypointense on T1-wt images and hyperintense on T2-wt images; on DWIs, the lesion shows diffusion restriction.,,
Differential diagnosis would include dermoid, meningocele, neurenteric cyst, abscess, rectal duplication cyst, or a tail gut cyst. Dermoid, tailgut cyst, and neurenteric cyst usually have associated bony defects. Additionally, the tailgut cyst and dermoids would appear hyperintense on T1-wt images owing to the presence of mucoid material and fat, respectively. Meningocele shows dural sac communication whereas rectal duplication cysts are anterior to the rectum and show communication with the rectum.,
Although an abscess and epidermoid both show similar features on the MRI along with diffusion restriction, the differentiating features seen in an abcess would include a thick enhancing wall, intracavitary air and fluid debris, and thickened rectal wall with surrounding fat infiltration; clinically, it would be associated with history of fever, systemic illness, or recent surgery.
Errors in a preoperative diagnosis have been reported even with MRI and DW studies, wherein a presacral epidermoid was preoperatively assumed to be a meningocele.,
In this case, the lesion appeared to be in continuity with the thecal sac at the level of S2 [Figure 2] and [Figure 5], and the contents mimicked CSF intensities on MRI. Thus an anterior sacral meningocele was strongly suspected. However, as the contents also showed diffusion restriction, a diagnosis of an epidermoid within an anterior sacral meningocele was assumed. Such coexistence of an epidermoid with a sacral meningocele in this location is well documented.,,
Although this did not affect the final outcome of surgery, an associated large meningocele deserves urgent attention to prevent a potential life-threatening meningitis.
The approach to surgery for a presacral tumor can be varied and depends on the anatomic extent of the disease., Anterior approach is recommended when the tumor mass extends above the level of S3,,, whereas a posterior approach is used when the mass is located below the midbody of S3 without involvement of adjacent organs.,, A combined approach may be used for adhesions or invasion into adjacent structures.,
Clinically, if the superior pole of the lesion can be reached on digital rectal examination, they can be removed via a posterior approach.,,
Intraoperatively, the tumor cavity contained keratinous material; there was no communication of the tumor with the thecal sac highlighting the fallacy of the MRI. This is attributed to the CSF and epidermoid showing similar signal intensities and sacral agenesis below S2. The thin anterior dura in the sacral area makes it difficult to visualize the tumor as being separate from the thecal sac.
During surgery, it is imperative to identify the ureters and iliac vessels and to prevent injury to the autonomic nerves in the pelvic floor. Athough a plane of cleavage does exist between the tumor and the surrounding organs, it may be difficult to dissect the tumor off the posterior part owing to large size, poor visibility, and profuse bleeding from the presacral plexus., We found that it is easier to puncture the tumor capsule anteriorly and decompress the contents to easily manage the posterior dissection. A laparoscopic or robotic method may yield better visualization and ease of dissection.,
To prevent recurrence and complications, total excision of the cyst wall is recommended.
| Conclusion|| |
Exclusive presacral epidermoids may create a preoperative diagnostic misperception as they are known to coexist with anterior sacral meningocele. Owing to its common association with sacral agenesis, MRI may be misleading in cases in which these large presacral tumors are in direct contact with the thecal sac and may give a false impression of the meningocele. MRI with diffusion-weighted sequences should be part of the imaging protocol for all cystic lesions in the sacral region as it helps in better differentiation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/havegiven his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials willnot be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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