Objective: To study the clinicopathologic features, immunophenotype and gene rearrangement of primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL).
Methods: Seven cases of PCLBCL were enrolled into the study. Clinicopathologic analysis, immunohistochemical staining and gene rearrangement for IgH and Igκ were undertaken in the study.
Results: All the seven cases were male, and the median age was 72 years. Patients usually presented with multiple purple tumors, nodules, papules and infiltrative plaques. Two patients had a history of leg injury before onset, and one had mosquito bites. Histologically, the tumor involved the dermis and subcutis with dense and diffuse infiltrative pattern composing of centroblasts and/or immunoblasts. Immunohistochemical staining showed that seven cases (7/7) expressed CD20, six (6/6) expressed bcl-2, four (4/4) expressed MUM-1, four (4/5) expressed CD79a, four (4/5) expressed PAX-5 and four (4/6) expressed bcl-6, respectively. All cases did not express CD3ε, CD45RO, CD10 and CD30. IgH gene rearranged bands were detected in three (3/6) cases and Igκ was detected in one (1/5) case. Six of the seven cases died and the remaining patient, who was 44-year-old, was alive after 22 months of follow-up.
Conclusions: PCLBCL is rare, predominantly affects elderly male patients. PCLBCL has poor prognosis and high mortality, but younger patients seem to have better prognosis. Some cases had a history of trauma or mosquito bites. The relationship between the history and the onset of PCLBCL needs further evaluation.