Intradural-Intramedullary Spinal Teratoma with Syrinx Formation: A Case Report

Abstract

Spinal teratomas, though rare among spinal tumors, should be considered in the differential diagnosis of intradural-intramedullary lesions, especially in children presenting with urinary and fecal symptoms. Comprehensive imaging evaluation, including CT and MRI with characteristic findings such as cystic and solid components, the presence of fatty tissue, and associated spinal cord abnormalities like syrinx formation, can aid in early diagnosis. Surgical resection remains the mainstay of treatment, and prompt intervention is crucial to prevent progression and alleviate symptoms in affected patients. Here, we discuss a case of an intradural-intramedullary teratoma in a 6-year-old child who was timely diagnosed using CT and MRI and treated with total surgical resection.

Introduction

Spinal cord tumors constitute 1% to 10% of all central nervous tumors in the pediatric population. ¹ About one-third of these tumors are intramedullary, of which the majority (80%-90%) are gliomas.^2,3 Teratoma, a type of germ cell tumor containing tissues derived from ectoderm, mesoderm, and endoderm, are extremely rare among spinal tumors. Excluding the sacrococcygeal region, they only account for 0.2% to 0.5% of all spinal tumors and predominately affect males. ⁴

Spinal teratoma may be associated with cord abnormalities like spina bifida, tethered cord syndrome, diastematomyelia, syringomyelia, and hydromyelia. Association with cord abnormalities is more common in children than in adults. ⁵ Here we present a case of a child with intradural-intramedullary teratoma with associated syrinx formation.

Case Presentation

This is the case of a 6-year-old boy who was brought to the outpatient department (OPD) of our hospital by his parents for the evaluation of his underlying medical condition. The parents mentioned that the child had 2 episodes of lower abdominal/suprapubic pain and distention and urinary and fecal retention in the past 8 months. There was no associated fever or vomiting with these episodes. Each episode was managed with urinary catheterization, analgesics, and laxatives at a local hospital. The child was born at term and had achieved age-appropriate developmental milestones. He had no other pathological history.

On examination in the OPD, the child appeared normal, appearing to have no abdominal or back pain. The abdomen was soft, non-tender, and non-distended. Neurological examination revealed normal motor and sensory functions in all limbs. Deep tendon reflexes were normal as well. Anal reflex was present and resting sphincter tone was 4 according to digital rectal exam scoring system (DRESS). Examination of rest of the systems was normal.

A review of his past medical record revealed that he was diagnosed with diastematomyelia in the cord on a CT abdomen. Assuming this to be the likely cause of the past episodes of urinary and fecal retention in the child, a CT scan and an MRI of the spine were ordered. A CT scan showed a heterogenous lesion in the central canal with internal calcifications and a fatty component extending from D12 to L2 vertebral levels (Figure 1). MRI demonstrated an intradural intramedullary heterogenous signal intensity area in the right posterolateral aspect of the distal spinal cord and conus medullaris opposite the D12 to L2 vertebrae, measuring 3.7 × 1.3 × 1.3 cm (CC × AP × TR). There was retrograde dilation of the central canal of the spinal cord from D2 till D11, appearing as a syrinx, due to compressive effect of the above mentioned mass lesion. These findings were suggestive of an intradural intramedullary teratoma associated with syrinx formation in the spinal cord (Figures 2 and 3). Diastematomyelia was not visible in the current scans, showing a misinterpretation of syringomyelia as diastematomyelia on the previous CT abdomen. Additionally, there was significant fecal loading noticed in the CT and MR studies, which was consistent with the history of fecal retention (Figures 1 and 3).

Figure 1.

Plain CT lumbosacral spine (sagittal sections) show a mixed density intradural intramedullary lesion (black circle) with internal calcifications and fatty attenuation areas extending from D12 to L2 vertebral level in soft tissue window (A) and bone window (B).

Figure 2.

Axial sections of MRI lumbosacral spine T1 (A), T1 post-contrast (B) and T2 (C) sequences show an altered signal intensity area (white arrows) having internal fatty, cystic and solid components with mild heterogenous and peripheral post-contrast enhancement.

Figure 3.

Sagittal sections of MRI spine show an altered signal intensity area (white arrows) in T1 (A), T2 (B), FLAIR (C), and STIR (D) sequences opposite the D12 to L2 vertebrae having internal fatty, cystic and solid components. The central canal of spinal cord is dilated from D2 to D11 resulting in syrinx formation.

The child was referred to a pediatric neurosurgeon, where he underwent a total resection of the teratoma. Histopathological examination of the mass revealed mature components comprising neural tissues, adipose tissues, bony tissues, and keratinized squamous epithelium, with no evidence of malignant components. The post-operative course was uneventful and the child was discharged home on the fifth post-operative day. On follow-up at the first month, the child had no episodes of urinary or fecal retention, and a repeat MRI scan showed no evidence of recurrence. The child continued to be monitored over the course of 1 year with follow-up visits every 3 months, during which no bladder or bowel complaints were reported. An MRI scan done 1 year after surgery showed no recurrence.

Discussion

Teratomas are commonly seen in the ovaries and testes. Extragonadal teratomas arise in midline locations. The anterior mediastinum, retroperitoneum, and pineal regions are common locations in adults, while the sacrococcygeal region is common in infants and children. Teratomas are a rare entity in the spinal cord and constitute less than 0.5% of all spinal tumors. ⁴ They can be extradural, intradural-extramedullary, or intradural-intramedullary. In children, they are commonly intramedullary and mostly involve the thoracolumbar region, as observed in our case, where intradural-intramedullary teratoma was present at the D12 to L2 level. ⁶

The clinical presentation of spinal teratoma depends on the region of the spinal cord involved. The most common symptoms are back pain, limb weakness, gait disturbance, and bladder or bowel dysfunction. In our case, the child had complaints of urinary retention and constipation with no back pain or limb weakness. Teratomas are slow-growing tumors. So the symptoms are progressive rather than sudden or acute. Any sudden onset or alteration of symptoms should promptly be investigated for an immature or malignant teratoma. ⁷

A definitive diagnosis of spinal teratoma is difficult to make preoperatively. The definitive diagnosis often requires histopathology following surgical resection of the teratoma. CT scans and MRIs cannot differentiate between teratomas and other intramedullary tumors. However, with the advancement in MRI techniques, early and definitive diagnosis of spinal teratoma has been possible, especially when an MRI signal characteristic compatible with cystic and solid components along with the presence of fatty tissue is associated with spinal cord abnormalities like spina bifida, tethered cord syndrome, diastematomyelia, and syringomyelia. ⁸ In our case, teratoma was associated with syrinx formation from D2 to D11. Table 1 summarizes the other reported cases of spinal teratoma associated with syringomyelia in the pediatric population. With an MRI, the child was diagnosed earlier, when he had no other complaints except for 2 episodes of urinary retention and constipation. Histopathology following tumor resection confirmed the diagnosis of spinal teratoma in the child.

Table 1.

Summary of other reported cases of spinal teratoma with associated syringomyelia in pediatric population.

Authors	Age/sex	Signs and symptoms	Site of teratoma	Location	Treatment	Histology	Outcome
Sharma et al 5	1. 1/M	1. Swelling lower back	1. L3	1. Intradural-extramedullary	1. Total resection	1. Mature	Not mentioned individually
	2. 3/F	2. Swelling lower back	2. L3	2. Intradural-extramedullary	2. Total resection	2. Mature
Kumar and Singh 9	8/M	_	D7-D10	_	Near total resection	Mature	No change
Işik et al 10	5/F	Paraparesis, neck stiffness	T12-L2	Intramedullary	Total resection	Mature	improved
Our case	6/M	Intermittent urinary retention, constipation	D12-L2	Intradural-Intramedullary	Total resection	Mature	improved

As observed in our case, teratoma on MRI characteristically appears as a lobulated, encapsulated cystic mass that contains fatty tissue and displays a hyperintense signal on T1 and T2WI, a hypointense signal on fat suppression sequences, and a mild post-contrast enhancement. They have areas of calcification that mostly display a hypointense signal on all sequences. CT can be useful to identify the area of calcification with certainty, especially in cases where bones are involved. ¹¹ X-rays show nonspecific findings like elongation of intervertebral space and vertebral body erosion.

Total surgical resection is the mainstay of treatment in symptomatic patients. Laminectomy and laminotomy can be used to expose tumors, with laminotomy preferred in young children under 3 years of age or for those requiring greater surgical exposure. Partial resection is preferred to prevent any risk of neurological deficit when the tumor’s capsule is attached densely to nearby neuronal structures.^3,12,13 Following tumor resection, histopathology of the mass is important to confirm the diagnosis and classify the teratoma as mature, immature, or malignant. Immature and malignant teratomas may require adjuvant chemotherapy and radiotherapy. ¹⁴ In our case, total surgical excision of the teratoma was achieved, which on histopathology was confirmed as a mature teratoma. Post-surgery clinical and radiological follow-up for a long duration is crucial to rule out any recurrence.

Conclusion

Prompt imaging, particularly of the conus medullaris, should be considered in pediatric patients presenting with fecal and urinary dysfunction, even in the absence of neurological signs or visible spinal abnormalities. Early identification can guide timely surgical or therapeutic intervention, improving outcomes.