Recurring headaches that persist over time. This is one of the most insidious symptoms of a brain tumor, as even an experienced physician may have considerable difficulty in differentiating between a headache that is a symptom of a tumor, and one that has a more mundane source.
It has been observed that headaches that are caused by tumors are exceedingly persistent on a daily basis, and will be all but impossible to be rid of. They will also become more intense as time passes, often manifesting in the early morning when the supine posture of sleep increases pressure in the cranium. Note that the intensity of the pain is no indication of the respective size or malignancy of the tumor.
Incremental damage to the eyesight. The damage to the vision (at first) might be so minimal that it may not even come to the conscious notice of the patient. Even if it does, the patient is unlikely to link it to a brain tumor. Often, the damage occurs incrementally over time, eluding the patient’s notice until it is so pronounced that the patient has difficulty in navigating around obstacles as they walk, or suffers successive accidents while driving. Such vision loss generally tends to be pronounced in one eye. The medical term for such visual impairment, especially peripheral, is bi-temporal hemianopsia.