Path. Res. Pract. 177, 1-7 (1983) Dep artment of Path ology, General Hospital of Athens, Greece Mucous Metaplasia of Epithelial Cells in Fibrocystic Disease of the Breast A Histochemical Study G. KONTOGEORGOS, V. BOUROPOULOU, and O. Th. ANASTASSIADES Summary Mucous metaplasia of breast epithehum was studied by histochemical procedures In cases of fibrocysnc disease. Epitheli al mUCInS consist almost entirely of non-sultated sralornucins. A slight amount of sulfated sialomucins was idennned occasionaly while neutral mUCInSseems to be absent. Abun- dant glycogen granules are contained In the cytoplasm of metaplas tic cells. The secretion ot sialomucms may he associated with a loss of cell antigenicity. In this case, the survival of metaplasnc epirhehu rn supports the hypothesis of the possible Immunological nature of the disease. In prev ious studies (Anasrassiades 1979, Anastassiades et aI., 1981) on histology and pathogenesis of fibrocystic disease of the breast, various types of metaplasia of the mammary epithelial cells were described. The commonest, although less recognized, type of epithelial metaplasia is mucous metaplasia. The present study is a further investigation of mucous metaplastic changes of breast epithelium for the determination of their histochemical characteris- tics. Material, Methods and Interpretation s The study was performe d m torrnalm-nxed, paratfm-ernbedded biopsy material from cases of fibro cystic disease of the breast. Sectio ns were stained With haemaroxylm and eosin and a battery of simple and combined histochermcal procedures, for the detection of the whole spectrum of eprrhelial rnucms (glycoprotein" according to Culling (1974). Frozen sections and sections from tissue specimens fixed in calcrurn torrnol were also used. I Path Ro, Pract \01 1--