Primary diffuse leptomeningeal gliomatosis with parenhycmal infiltration: A clinico- radio-pathological correlation

Abstract

Primary Diffuse Leptomeningeal Gliomatosis (PDLG), as first described by Moore (1954), is a very rare form of cancer resulting from the meningeal heterotopic astrocytes that convert into malignancies and possibly causing obstruction on the Virchow spaces leading to cystic parenchymal infiltration. This case, 4th documented case of atypical parenchymal infiltration, is a 45 -year old male with gradually progressive headache, difficulty sleeping and profound anxiety, left-sided numbness and seizures. Cranial CT- Scan showed right thalamic lesion without hydrocephalus. A possible thalamic infarct or cavernoma was considered. Subsequent MRI showed the same thalamic lesion but now with focal leptomeningeal enhancement probably secondary to glioma versus tuberculosis. He was given anti-Koch’s medications and steroids. Leptomeningeal biopsy confirmed this malignancy. Post- mortem autopsy revealed thickened leptomeninges, right thalamic mass involving the centromedial and posterolateral portion and small cystic lesions all over the surface. Histopathology showed Virchow -robin space infiltration proving the parenchymal involvement through the pial vessels. This case highlighted the possibility of parenchymal involvement which challenged the traditional diagnostic criteria and may now serve as a basis for a revised diagnostic criteria . In this case, imaging also showed an underestimation of the extent of atypical brain parenchymal infiltration. Hence, headache coupled by leptomeningeal enhancement should always warrant close imaging surveillance and possibly repeated biopsies to rule out this exceptional condition.