Primary Cutaneous B-Cell Lymphoma: An Update on Pathologic and Molecular Features

Abstract

Primary cutaneous B-cell lymphomas (PCBCLs) account for 25% of all primary cutaneous lymphomas. Three major types are currently recognized by the WHO classification: primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle centre lymphoma (PCFCL) (both considered indolent lymphomas) and primary cutaneous diffuse large B-cell lymphoma, leg-type (PCDLBCL-LT), which is, instead, a very aggressive disease. Nowadays, the PCBCL’s category also includes some rare entities such as intravascular B-cell lymphoma (IVBL) and the EBV+ mucocutaneous ulcer (EBVMCU). Furthermore, controversies still exist concerning the category of primary cutaneous diffuse large B-cell lymphoma (PCDLBCL), because some cases may present with clinical and histological features between PCFCL and PCDLBCL-LT. Therefore, some authors proposed introducing another category called PCDLBCL, not otherwise specified (NOS). Regardless, PCBCLs exhibit distinct features and differ in prognosis and treatment from their nodal/systemic counterparts. Therefore, clinicopathologic analysis is a key diagnostic element in the work-up of these lymphomas.

Primary Cutaneous Follicle Center Lymphoma Presenting as a Solitary Nodule on the Forearm of an Adolescent Girl: A Case Report and Literature Review

“…7,10,[15][16][17] Lucioni et al experienced a BCL2 positive expression in at least 25-27% of PCFCL cases. 18 BCL2 is considered helpful in the differentiation between PCFCL and systemic follicular lymphoma with secondary cutaneous involvement, which is usually positive in nodal follicular lymphoma and less often found in PCFCL. 17,19 The proliferation index (Ki67 staining) is usually lower than those seen in reactive follicles but some cases have shown high proliferation indices.…”

An Update on Recent Advances of Photodynamic Therapy for Primary Cutaneous Lymphomas

“…PLCs with B-cell origin are referred to as cutaneous B-cell lymphomas (CBCLs). Different types of CBCLs are primary cutaneous marginal zone B-cell lymphoma, primary cutaneous follicle center lymphoma, and primary cutaneous diffuse large B-cell lymphoma, leg type [ 31 , 32 ].…”

Evolution in the Definition of Follicular Lymphoma and Diffuse Large B-Cell Lymphoma: A Model for the Future of Personalized Medicine

“…This is an indolent disease that should be managed conservatively. However, if there is evidence of BCL2-R or BCL2 protein expressed, clinical evaluation is suggested to rule out secondary cutaneous involvement from a systemic FL [24][25][26].…”