Paediatric central nervous system (CNS) tumours are the second most common cancer in the 0 to 14 age group; additionally, they constitute the main cause of morbidity and death associated to cancer. Although intracranial hypertension-related and localization-related symptoms are the most frequent clinical features, onset symptoms may be nonspecific. Hence, a more accurate differential diagnosis is required. This paper presents nine cases of paediatric CNS tumour with atypical clinical onset. The first, a ganglioglioma, manifested as precocious puberty; the second, a pilocytic astrocytoma, presented with memory loss; the third, a medulloblastoma, initially manifested as dysphagia; the fourth, a pilocytic astrocytoma, presented with scoliosis; the fifth one, an ependymoma, manifested as a persistent back pain; the sixth, a low-grade glioma of the optic pathway, presented with an early pathological childhood nystagmus; the seventh showed symptoms of an urinary tract infection that hid the presence of an ependymoma; the eighth and the ninth presented with psychiatric symptoms in adolescence that concealed the presence of a pilocytic astrocytoma and a CNS germinoma. This research aims to emphasise the importance of recognising diverse onset symptoms to allow a prompt diagnosis and early treatment and ultimately to improve patient outcome.