Hepatitis Inflammation of the liver. Herpes Simplex Virus A virus that causes a disease marked by vesicles of the skin, usually on the lips, nares, or genitals. Hyperplasia An increase in the number of cells in a tissue.  This generally results in an enlargement of tissue mass and organ size. Hypertrophy An increase in size of individual cells.  This frequently results in an increase in the size of a tissue or organ.