Conditions Suggesting Lymphoma

ders. These entities constitute a spectrum of related cutaneous conditions originating from a transformed or activating CD30-positive T-lymphocyte. LP is a chronic recurrent skin disease characterized by appearance of papules and/or nodules, which regress spontaneously, typically within 3 to 6 weeks. Lesions greater than 2.5 cm may not regress completely and may leave residual scars with hypoor hyperpigmented skin. Histologically, there is an atypical T-cell infiltrate, which mimics a T-cell lymphoma. The putative cell of origin is an activated skin homing T-lymphocyte. Fully developed papules show wedge-shaped dermal infiltrates of atypical T-cells admixed with varying proportions of inflammatory cells such as neutrophils, eosinophils, macrophages, and small lymphocytes. The atypical T-cells may either simulate RS features akin to Hodgkin’s lymphoma or their nucleus may resemble the cerebriform appearance of mycosis fungoides. The presence of RS-like cells along with numerous inflammatory cells constitutes type A lesions, whereas accumulation of cells with cerebriform nuclei in the absence of inflammatory cells exemplifies type B lesions. Both lesions may exist in the same patient. Immunophenotypic features include CD3positive, CD4-positive, and CD8-negative T-lymphocytes. CD30 is present in type A lesions but may be absent in type B lesions. Anaplastic lymphoma kinase protein is consistently absent. Although clonally arranged TCR genes have been noted in the majority of type B lesions and occasionally in type A lesions, the t(2;5) translocation, which is a characteristic feature of ALCL, is universally absent. Due to the overlapping clinical (waxing and waning in borderline lesions), histologic (RS-like cells in Hodgkin’s lymphoma and cerebriform cells in mycosis fungoides), and immunohistochemical (CD30positive in ALCL and Hodgkin’s lymphoma) features, the diagnosis of LP requires vigilance by the hematopathologist and the oncologist to avoid unnecessary cytotoxic therapy, as highlighted in this case.