1. Case 6 F, 75 ys Erythematous nodule of the lower left leg

6. CD20

7. Bcl-6

8. Bcl-2

9. CD10

10. CD3

11. Mib-1

12. DIAGNOSIS  Diffuse large B cell lymphoma  Work-up: peripheral blood, bone marrow, CT scan: peripheral blood, bone marrow, CT scan: all negative all negative

13. Follow-up (after 17 months)  Local recurrence of the lesion  New biopsy  Same morphology  Subcutaneous tissue involvement  But...

15. CD5

16. Cyclin-D1

17. FINAL DIAGNOSIS  Primary cutaneous MCL, blastoid variant, with aberrant bcl-6/CD10 expression Cesinaro AM, Bettelli S, Maccio L, Milani M. Cesinaro AM, Bettelli S, Maccio L, Milani M. Cesinaro AMBettelli SMaccio LMilani M Cesinaro AMBettelli SMaccio LMilani M Primary Cutaneous Mantle Cell Lymphoma of the Leg With Blastoid Morphology and Aberrant Immunophenotype: A Diagnostic Challenge. Am J Dermatopathol. 2013 Apr 22. [Epub ahead of print]. Primary Cutaneous Mantle Cell Lymphoma of the Leg With Blastoid Morphology and Aberrant Immunophenotype: A Diagnostic Challenge. Am J Dermatopathol. 2013 Apr 22. [Epub ahead of print]. Am J Dermatopathol. Am J Dermatopathol.

18. FISH break apart (t11;14) Cyclin-D1+ ↑ Mib-1 CD5 -

19.  Work-up: peripheral blood, bone marrow and CT scan negative  Therapy: local radiotherapy  14 months later: ulcer of the tongue: MCL  Further work-up: peripheral blood, bone marrow and CT scan negative  Therapy: 3 cycles of chemotherapy  Recurrence and pulmonary complications  Death 40 months after first skin biopsy

20. PITFALLS in MCL diagnosis  Aberrant expression of B cell markers (CD10, bcl-6)  Sometimes negativity for CD5  Blastoid morphology: DD with diffuse large B cell lymphoma  Involvement of the skin, usually secondary  Very rare cases of bona fide primary cutaneous MCL Note: diagnostic value of IIC and FISH Note: diagnostic value of IIC and FISH