An inverted papilloma, also known as Ringertz tumour,[1] is a type of tumor in which surface epithelial cells grow downward into the underlying supportive tissue.

It may occur in the nose and/or sinuses or in the urinary tract (bladder, renal pelvis, ureter, urethra).

However, magnetic resonance imaging (MRI) may show a characteristic feature described as a convoluted cerebriform pattern (CCP).

A retrospective study published in the American Journal of Neuroradiology concluded that identification of CCP by MRI in a patient with a nasal tumor made the diagnosis of Inverted papilloma quite likely.

[citation needed] This article incorporates public domain material from Dictionary of Cancer Terms.