On cross sections, a small yellow-tan stone is present. The scarring is characterized by an increased amount of collagenous tissue around the ducts and acini. There is extensive atrophy of acini. The chronic inflammatory infiltrate consists of lymphocytes, with fewer plasma cells and macrophages. Obstruction is often a contributing factor to the development of inflammation, as normal flow of lumenal contents is blocked.
Infection is also more likely to occur in such a setting.
In this case, obstruction with chronic inflammation led to the scarring and atrophy.