Splenic epidermoid cyst (SEC) is a rare condition. We aimed to evaluate the immunohistochemical profiles of the epithelial lining of SECs. A total of 7 SEC cases were analyzed: 2… Click to show full abstract
Splenic epidermoid cyst (SEC) is a rare condition. We aimed to evaluate the immunohistochemical profiles of the epithelial lining of SECs. A total of 7 SEC cases were analyzed: 2 cases involved a monolayered epithelial lining and 5 cases involved a multilayered epithelial lining. Among the multilayered SECs, the superficial/luminal layer showed mucin 4 (MUC4), cytokeratin 5/6 (CK5/6), and CK7 expression in 5 cases (100%); MUC1, carcinoembryonic antigen (CEA), CA19-9, and thrombomodulin expression in 4 cases (80%); Wilms' tumor-1 (WT-1) and Hector Battifora mesothelial-1 (HBME-1) expression in 2 cases (40%), but it did not express p63 or D2-40. The basal layer expressed MUC1, CK5/6, p63, and thrombomodulin in 5 cases (100%); CK7 and WT-1 in 4 cases (80%); D2-40 in 3 cases (60%); CA19-9 and HBME-1 in 2 cases (40%) and MUC4 in 1 case (20%) but it did not express CEA. The analysis showed that all cases of multilayered SECs were negative for MUC2, MUC5AC, MUC6, CK20, calretinin, uroplakin-II, and uroplakin-III. Both cases of monolayered SECs expressed CK5/6, CK7, HBME-1, WT-1, and thrombomodulin but not MUC2, MUC4, MUC5AC, MUC6, p63, CEA, CK20, CA19-9, D2-40, uroplakin-II, or uroplakin-III. One case of monolayered SEC expressed MUC1 and calretinin. Our findings indicate that monolayered SECs have mesothelial-like characteristics, whereas multilayered SECs have glandular and squamous-like characteristics besides mesothelial-like characteristics. Furthermore, monolayered SECs may develop from mesothelial inclusion and monolayered SECs develop squamous and glandular metaplasia, which results in multilayered SECs.
               
Click one of the above tabs to view related content.