1A mass or other lesion that gives rise to signs or symptoms suggestive of a neoplasm but is non-neoplastic (usually inflammatory or hyperplastic) in origin.
2More fully pseudotumour cerebri. A syndrome characterized by increased intracranial pressure occurring in the absence of an intracranial mass or abnormality of the cerebral ventricles.
Origin
Mid 19th century; earliest use found in Todd's Cyclopaedia of Anatomy and Physiology. From pseudo- + tumour.