Diffuse Leptomeningeal Glioneuronal Tumor

A 7-year-old patient with history of neuroblastoma 5 years prior, who remained disease free for 3 years, presented with headache and seizures. Head CT (Computed Tomography) and MRI (Magnetic Resonance Imaging) were performed due to suspicion of recurrence with CNS (Central Nervous System) affection.

Initial brain MRI showed multiple cyst-like spaces within the white matter of both brain and cerebellum. There was also leptomeningeal enhancement both at the basal cisterns and subarachnoid space. Antituberculosis therapy was started as CSF (Cerebro Spinal Fluid) protein count was high while glucose was normal. Specific tests for TB (Tuberculosis) were negative.

The seizures persisted and the patient was sent for a follow-up CT 3 months later that showed enlargement of the previously identified lesions as well as hydrocephalus. A VP-shunt (Ventriculoperitoneal shunt) was placed.

A follow-up brain MRI 6 months later demonstrated worsening of the imaging features, adding to them brain atrophy. A brain biopsy was obtained. The patient died 1 month later.

Diffuse leptomeningeal glioneuronal tumour is a relatively new entity described in the 2016 World Health Organization classification of brain tumours [1]. It affects almost exclusively children, although cases in adults have been described [2].

The course of the disease is indolent tumour due to a low proliferation rate; however, up to 63% of patients die within 9 months after diagnosis [3]. Diagnosis may be delayed, as symptoms are non-specific, particularly those derived from hydrocephalus, and CSF analysis shows high protein count with normal glucose, features compatible with meningeal tuberculosis [4].

Imaging features include diffuse intracranial nodular leptomeningeal thickening, diffuse intraspinal nodular leptomeningeal thickening, and intramedullary spinal cord mass, cystic enlargement of Virchow-Robin spaces, and hydrocephalus [5].

No treatment consensus has been established, although radiation therapy and multiple chemotherapeutic regimens can reach some stabilization of the disease when started early [6].

Our patient´s case was misdiagnosed as tuberculous meningitis because he had been in contact with relatives who had tuberculosis as well as the result of the spinal fluid analysis. This was also the reason why metastasic diseas was ruled out and led to the delay in the diagnosis for 6 months, until a biopsy was obtained. No spinal imaging was obtained because he was believed to have meningitis.

Conclusion

Radiologists must know this entity and its imaging features as the differential diagnosis may be challenging particularly in tuberculosis endemic areas. Its early identification and treatment are key for the patient´s survival.

Written informed patient consent for publication has been obtained.