Article : Primary Cutaneous Follicle Center Lymphoma and Its Molecular Landscape

Angelica Selim, MD reviewing Szablewski V et al. Am J Surg Pathol 2016 Jan.


New research alerts us to a PCFCL subset affecting mainly head and neck with genetic alteration [t(14;18)] and immunoprofile (CD10+, BCL-6+, BCL2+, STMN+) similar to the nodal type, but with a benign course.

Primary cutaneous B-cell lymphomas are non-Hodgkin lymphomas of skin without evidence of extracutaneous disease or within 6 months of diagnosis. Primary cutaneous follicle center lymphoma (PCFCL) — neoplastic proliferation of follicular centrocytes or centroblasts affecting the head or trunk of middle-aged adults — is one such lymphoma. Detection of BCL-2 protein, which correlates with BCL2 translocation, is commonly used to differentiate PCFCL from secondary cutaneous follicular lymphoma (SCFL).

In 25 follicular lymphomas without extracutaneous disease and reactive to BCL2 clones 124 and E17, subjected to interphase fluorescence in situ hybridization with BCL2, BCL6, IGH, IGK, IGL breakapart, IGH-BCL2 fusion, and 1p36/1q25 dual-color probes, there were 19 that were BCL2-positive cases and 6 negative ones. Among PCFCL cases, 15 were BCL2-positive and 5 were BCL2-negative. After a median 2-year follow-up, 4 cases developed systemic involvement or SCFL and were eliminated.

Mean age of PCFCL patients was 63.5 years with male predominance. Head and neck were the most frequently affected areas for BCL2+ PCFCLs. No significant differences in histologic features were noted between BCL2+ and BCL2– PCFCLs. Expression of CD10 and BCL6 was most frequent in BCL2+ PCFCLs; 60% of PCFCLs showed a BCL2 break, t(14;18)(IGH/BCL2), and expression of CD10, BCL6, BCL2, and STMN like nodal follicular lymphomas. Deletion of 1p36 was detected in one PCFCL.


Citation(s):

Szablewski V et al. Primary cutaneous follicle center lymphomas expressing BCL2 protein frequently harbor BCL2 gene break and may present 1p36 deletion: A study of 20 cases. Am J Surg Pathol 2016 Jan; 40:127.

 

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