Nonneoplastic Cystic Lesions of the Central Nervous System-Histomorphological Spectrum: A Study of 538 Cases.

A wide spectrum of non-neoplastic cystic lesions can occur in the central nervous system (CNS). These are uncommon, benign and of diverse aetiology, pathogenesis and clinical presentation.The spectrum of these lesion varies based on the location and in turn histogenesis. To evaluate the pathologic spectrum of non-neoplastic cystic lesions in the CNS (both developmental and acquired) and highlight the role of histopathology in the diagnosis of these cystic lesions. This was a retrospective study done at Department of Neuropathology,NIMHANS. All the histologically diagnosed non-neoplastic cystic lesions of CNS submitted to the Department of Neuropathology between 2014 and 2017 were reviewed in this study. The data was analysed in relation to the type of cysts, location(intracranial and spinal), and clinical profile using SPSS software version 17.0. The study included 538 cases with patient age ranging from 5 months to 90 years [M:F:1:1.05]. Non-infective cysts (489/538, 90.8%) predominated over the infective cysts (49/539, 9.2%) with epidermoid cysts (132/538, 24.5%) being the most frequent one followed by colloid cysts (126/538, 23.4%) and arachnoid cysts (111/538,20.6%). The most common infective cyst was neurocysticercosis (42/538, 7.8%) followed by hydatid cyst (7/538, 1.3%). Intracranial cysts (415/538, 77.1%) were more common than spinal ones (123/538, 22.9%). Conclusions: A variety of cystic lesions occur in the CNS with overlapping clinical features, image findings and lining. Hence, histological analysis plays a crucial role in the evaluation of these lesions.