Edit page | Page history | Printable version

null-cell adenoma

(Science: tumour) An adenoma of the hypophysis composed of cells for which there is no overt evidence or hormone production, but which usually produces hypopituitarism and visual disturbances by compression of adjacent structures; approximately one third of these tumours have cells with abundant mitochondria (oncocytes) that are somewhat larger than the monocytic null cells.

Synonym: undifferentiated cell adenoma.