Giant cavernous malformations (GCMs) constitute an uncommon entity in the diagnostic armamentarium of the neurosurgeon. We report a 3-year-old boy with a GCM in the peri-trigonal region and review 13 other paediatric cases previously reported in literature. A 3-year-old boy presented with right-sided hemiparesis and features of raised intracranial pressure of short duration. Computed tomography showed a large left peri-trigonal mass with a bleed. Magnetic resonance imaging showed associated perilesional edema and mass effect, rendering the lesion a tumefactive appearance. He underwent total excision of the lesion, with subsequent recovery of hemiparesis. Histopathology was reported as a cavernoma. The clinico-radiological presentation of GCM is discussed based on a case report and relevant cases in literature. Good surgical outcome can be expected with total microsurgical excision. A giant cavernous malformation should be one of the differentials of a lesion with a tumefactive clinico-radiological presentation in children. There should be a high index of suspicion for such a diagnosis, especially when the lesion does not enhance with contrast. This is the third case report in paediatric literature describing a periventricular location of this unusual lesion.