1. Case 5 M, 78 ys Violaceous plaque on the penis History of nodal Mantle Cell Lymphoma (courtesy Prof. A. Maiorana)

6. CD20

7. CD3

8. CD5

9. Bcl-6

10. Cyclin-D1

11. Mib-1

12. DIAGNOSIS  Cutaneous localization of Mantle Cell Lymphoma Mantle Cell Lymphoma  FISH: presence of t(11;14)(q13;q32)

13. t(11;14)(q13;q32)  Translocation between IGH and cyclin D1 (CCND1) genes  It causes overexpression of CCND1 mRNA and protein cyclin D1  Cyclin D1 overcomes the cell cycle suppressors RB1 and p27/kip1  MCL: other secondary chromosomal aberrations

14. Mantle Cell Lymphoma  Main differential diagnoses: - B-CLL: cyclin-D1 -; no t(11;14)(q13;q32) - B-lymphoblastic lymphoma: TdT +; CD5 - cyclin-D1 - - Blastic plasmocytoid dendritic cell neoplasm: CD4 +; CD56 +; CD123 + - Merkel cell carcinoma: CK20 +; NF +; chromogranin +