Recurrent intramedullary endometriosis of the conus medullaris: A case report of diagnostic pitfalls and a review of literature

INTRODUCTION: Endometriosis is a common gynaecologcial disorder and is characterized by the presence and implantation of endometrial epithelium and glandular stroma in an extrauterine location Intraspinal endometriosis can involve the intramedullary, subarachnoid, intradural-extramedullary, and extradural compartments, including the vertebral bodies. Symptoms due to intraspinal endometriosis will vary depending on the location and degree of compression of neural structures and will fluctuate with the menstrual cycle. PRESENTATION OF CASE: A 20-year-old Sri Lankan female with recurrent catamenial backpain, presented to the neurosurgical clinic with acute cauda equina syndrome. She had a history of cyclical lower back pain and lower limb radiculopathy and had undergone spinal decompression and excision of a haemorrhagic cyst in the conus medullaris on three occasions over the past three years. Clinical, radiological and histological discordance meant that the diagnosis of intraspinal endometriosis was missed previously. She underwent repeat spinal decompression on this occasion with histology confirming an endometrial cyst. DISCUSSION: Intramedullary spinal cord haematomas are rarely encountered in neurosurgery. Vascular or neoplastic causes are common with endometriosis being extremely rare. The lack of clinical suspicion, radiological imaging supporting an alternate diagnosis, along with lack of histological confirmation led to the initial diagnostic dilemma and delays in starting long term endometrial suppression therapy. CONCLUSION: Intraspinal endometriosis is a rare but important differential diagnosis in the evaluation of a female in the reproductive age group with cyclical lower back pain and neurological symptoms. One must have a high degree of suspicion regarding it, in order to prevent protracted morbidity.