<unk>  (PCDLBCL, LT) (also termed PCDLBCL,<unk> <unk>  or<unk><unk>  DLBCL,<unk> <unk>  is a<unk>  lymphoma skin disease that occurs mostly in elderly females. In this disease,<unk> -cells (a<unk>  of lymphocyte)<unk> ecome malignant, accumulate in the dermis (i.e. the layer under the epidermis) and subcutaneous tissue<unk> elow the dermis to form red and violaceous skin nodules and tumors. These lesions typically occur on the lower extremities<unk> ut in uncommon cases may develop on the skin at virtually any other site. In ~10% of cases, the disease presents with one or more skin lesions none of which are on the lower extremities; the disease in these cases is sometimes regarded as a variant of PCDLBL, LT termed<unk><unk><unk>  large<unk> -cell lymphoma, other (PCDLBC-O). PCDLBCL, LT is a subtype of the<unk>  large<unk> -cell lymphomas (DLBCL) and has<unk> een thought of as a<unk>  counterpart to them. Like most variants and subtypes of the DLBCL, PCDLBCL, LT is an aggressive malignancy. It has a 5-year overall survival rate of 40-55%, although the PCDLBCL-O variant has a<unk> etter prognosis than cases in which the<unk> s are involved. Most lymphomas<unk> egin in a lymph node, mucosa-associated lymphoid tissue, the spleen, or another lymphoid tissue within the lymphatic system and then may spread to the skin. In these cases the skin is a secondarily site of involvement. PCDLBC, LT is a<unk><unk>  lymphoma, i.e. it<unk> egins in the skin and then may spread to lymphoid and/or non-lymphoid tissues in virtually any other site. A suspect PCDLBCL, LT that is not limited to the skin at the time of diagnosis should<unk> e regarded as some other variant or subtype of the<unk>  large<unk> -cell lymphomas. PCDLBC, LT represents 5-10% of all<unk><unk>  lymphomas. It is to<unk> e distinguished from two other<unk><unk>  lymphomas that involve<unk> -cells,<unk><unk>  follicle center lymphoma (PCFCL) and<unk><unk>  marginal zone lymphoma (PCMZL), as well as from a<unk> -cell lymphoma that at diagnosis may appear to<unk> e limited to the skin<unk> ut often is a systemic disease affecting numerous organs and tissues viz., intravascular large<unk> -cell lymphoma (IVLBCL). These three<unk> -cell lymphomas differ from PCDLBCL, LT in numerous ways<unk> ut most importantly in their aggressiveness. IVLEBC is, like PCDLBCL, LT, an aggressive disease with a guarded prognosis,<unk> ut unlike the former disease, is often widely disseminated at presentation. PCFCL and PCMZL, in contrast, are indolent lymphomas with a relatively good prognosis. Distinguishing<unk> etween these four<unk> <unk> -cell lymphomas at the time of diagnosis is critical for their appropriate treatment.
Primary cutaneous diffuse large B-cell lymphoma, leg type
Secondary cutaneous CD30+ large-cell lymphoma
Primary cutaneous marginal zone lymphoma
Primary cutaneous follicle center lymphoma
Primary cutaneous immunocytoma
CD30+ cutaneous T-cell lymphoma
Non-mycosis fungoides CD30− cutaneous large T-cell lymphoma
Chronic multifocal Langerhans cell histiocytosis