Plasma cell gingivitis is a rare, benign inflammatory condition of unknown aetiology. It is said to be a type 4 hypersensitivity reaction to the irritant. It is also known as atypical gingivitis, plasmacytoma of gingiva, and plasma cell gingivostomatits. It requires histological and haematological investigations to confirm the diagnosis. Parole chiave: Plasma cell gingivitis, atypical gingivitis