Astrocytoma Mimicking a Collision Tumour of Astrocytoma-Meningioma - A Rare Interesting Morphological Phenomenon

Background: Astrocytoma and meningioma, being two of the most common tumours of glial cells and cells of leptomeninges respectively, are known to occur together in a pattern referred to as collision tumour. Being presented here is a case report of a unique tumour of astrocytes which presented with morphological features of both astrocytoma and meningioma mimicking a collision tumour of astrocytoma-meningioma, a rare interesting morphological phenomenon. Case report: The case being reported here is of a middle-aged male presenting with right-sided muscular weakness and frequent episodes of headache which on diagnostic image screening studies was diagnosed as a left parieto-occipital brain tumour. Microscopic examination of the resected lesion revealed an interesting and enigmatic morphological phenomenon which mimicked a collision tumour of astrocytoma and meningioma, though the conclusive diagnosis of the lesion was Astrocytoma, high grade (Glioblastomamultiforme) as revealed by ancillary studies such as immunohistochemistry. Conclusion: The current case report being presented here is of an astrocytoma which exhibited an enigmatic morphological phenomenon of having conventional microscopic features mimicking collision tumour of astrocytoma and meningioma which turned out, on immunohistochemical studies, to be a single high grade astrocytoma, a fact which has dire prognostic implications in terms of clinical management modalities of unwarranted additional two of the most common primary brain tumours. They are usually present as a solitary mass.It is rare to see the two conditions together. The usual way to confirm the presence of these two conditions is by histopathological examination and immunohistochemistry. Histopathological exam may usually be sufficient and may not warrant the requirement of an immunohistochemistry test. In cases where there is relevant doubt due to insufficient positive features on histopathological examination, the immunohistochemistry findings help in conclusive diagnosis of astrocytomas.