his·to·pa·thol·o·gy 
(hĭs′tō-pə-thŏlə-jē, -pă-)
(hĭs′tō-pə-thŏlə-jē, -pă-)n.
The study of the microscopic anatomical changes in diseased tissue.
his′to·path′o·logic (-păth′ə-lŏjĭk), his′to·path′o·logi·cal adj.
his′to·path′o·logi·cal·ly adv.
his′to·pa·tholo·gist n.