Diastematomyelia

The patient presented with abdominal pain, changed stool colour, vomiting and tiredness. At clinical examination a mass was found in the upper abdomen. The patient had no neurological symptoms.

Contrast-enhanced CT of the chest and abdomen was performed as a malignant disease was suspected. The scanning showed enlarged liver with diffuse parenchymal changes in keeping with possible acute hepatitis. As an incidental finding a sagittal osseous septum through the spinal canal at the L1-level was detected (Fig. 1-3). Additionally the L1 vertebra was found to have an enlarged spinosus processes with a central cleft (Fig. 3). No other abnormalities were seen in the spine and the diagnosis of diastematomyelia was made. Subsequent MRI performed to assess the liver changes confirmed the diagnosis of diastematomyelia (Fig. 4). No malignant disease was detected at CT or MRI. Acute viral hepatitis (CMV) was made by serology.

Diastematomyelia is a rare congenital abnormality in which the spinal cord is split in two parts (often by a rigid osseous septum). Diastematomyelia accounts for approximately 4% of all congenital spinal abnormalities. It is the result of the fetus having an accessory neuroenteric canal which causes the spinal elements to form as two sets of structures [1]. The lumbar and thoracolumbar region is the most common site for diastematomyelia with 50% occurring between L1 and L3, and 25% occurring between T7 and T12 [2]. Two types of diastematomyelia have been described: Type 1 (classic diastematomyelia) with duplicated dural sac with a midline spur, and type 2 with a single dural sac. The deformity is often accompanied by segmental anomalies of the vertebrae [3].
Patients with diastematomyelia may present with neurological signs and symptoms, but some patients are asymptomatic. The symptoms have shown to be significantly higher in type 1 than in type 2 diastematomyelia [1]. Patients with type 2 may be minimally affected or entirely asymptomatic.
Symptomatic patients can present with neurologic deficits in the lower limbs and perineum; causing leg weakness, low back pain, muscular atrophy, reflex changes and incontinence. Associated abnormalities may be present including congenital scoliosis, foot deformities and characteristic changes of the dorsal skin.
Surgical treatment with extirpation of the osseous septum (and duralplasty) is recommended for type 1 diastematomyelia, whereas conservative treatment is recommended for asymptomatic type 1 and all cases of type 2 diastematomyelia [4, 5]. For symptomatic patients correct diagnosis is important for optimal management and treatment before progression of neurological deficit. The present case is a case of type 1 diastematomyelia. The patient was asymptomatic and conservative treatment was chosen. Cross-sectional imaging with CT and MRI are the best imaging modalities to diagnose diastematomyelia. The bony structures are best evaluated with CT whereas the spinal cord should be evaluated with MRI.
In conclusion, diastematomyelia is a rare abnormality of the spinal cord with typical imaging findings at CT and MRI.

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