Details
A 79-year-old female with history of chronic NK-Cell proliferative disorder presents with skin lesion on her thigh.
Diffuse large B-cell lymphoma, leg type (DLBCL-LT) is a cutaneous diffuse large B-ceil lymphoma which typically arises from the skin of the leg, although it can involve other parts of the body.
Clinically, it mostly affects elderly women who present with rapid growing single or multiple erythematous nodules, plaques or non-healing ulcers in one or both legs. Microscopically, skin tissue reveals marked histopathologic changes in the dermis. There is a narrow zone (Grenz zone) separating the epidermis from a dense, diffuse (not follicular) sheet-like infiltration of highly atypical, large round cells mainly with the appearance of immunoblasts (large cells with vesicular nucleus as well as central prominent nucleolus).
Diagnostic immunophenotype for DLBCL-LT:
- The neoplastic B-cells usually express CD20
- Most cases of DLBCL-LT are positive (nuclear staining) for IRF4/ MUM1
- Strong cytoplasmic staining of BCL2
- BCL6 can be found in a number of cases
- CD10 is usually negative.
In this case, CDl0 and BCL6 are negative, whereas MUM-l/IRF4, CD20 and BCL2 show moderate to strong positive staining.