Presacral tumours are rare and can be challenging to diagnose and treat. Because the retrorectal space contains multiple embryological remnants derived from various tissues, the tumours that develop in this space are heterogeneous. Lesions are classified as congenital, neurogenic, osseous, inflammatory or miscellaneous. Although treatment depends on diagnosis and anatomic location, most retrorectal lesions will require surgical resection.1
Symptoms on presentation can be back pain, constipation, neurological symptoms or defecatory dysfunction due to compression, and some cases are detected incidentally.2 3
Rectal examination is useful in detecting retrorectal masses.4
Misinterpretation of symptoms and diagnosis of irritable bowel syndrome has been reported in many pelvic pathologies,5 6
and even on strict adherence to Manning and Rome criteria I and II for case definition of irritable bowel syndrome the percentage of concordance is low.7
The diagnosis of irritable bowel syndrome is a diagnosis of exclusion, especially when red flag signs are present. In this case the delay of 4 years from presentation to diagnosis is unacceptable for a mass of such a size, especially when urinary symptoms were also present. Diagnostic difficulty arises in cases that are asymptomatic. Our patient was symptomatic, with urinary symptoms in addition to those of defecation, and even a properly performed digital rectal examination would have picked up the mass.
Retrorectal or presacral masses are classified as per the tissue of origin and pathology (). Neurogenic lesions typically arise from peripheral nerves and represent about 10% of retrorectal tumours. These tumours include neurofibromas and sarcomas, neurilemmomas, ependymomas, schwannomas and ganglioneuromas. Ependymomas are most common. Pain and neurological dysfunction are often presenting symptoms and are related to the route of the involved nerve. Tumours arising from the sheath of lumbar root four and descending into the pelvis as a pedunculated mass have not been reported in the literature to date. Our patient had no pain related to the nerve root of origin, probably because of support by pelvic structures and no stretching of the root. This was more evident postoperatively as the defecatory dysfunction, which was pressure related, improved, and there was no neurological deficit related to the root of origin. Radical resection is usually required, but overall survival seems to be good.8
Presacral schwannomas with degeneration and calcification have been reported, with favourable outcome after resection.9
Classification of retrorectal masses
Therefore, review of symptomatology and appearance of red flag signs in a case of irritable bowel syndrome must be considered with extreme caution and re-evaluation considered at any stage of illness to diagnose a coexisting grave pathology.
- Diagnosis of irritable bowel syndrome must be made with caution, especially when atypical symptoms or red flag signs are present, and re-evaluation must be made to rule out any coexisting grave pathology.
- Pedunculated neurogenic tumours arising from the lumbar root and occupying the presacral area are reported here for the first time.
- Proper examination, including digital rectal examination, must be performed to rule out underlying grave pathology.