Activation-induced cytidine deaminase expression in diffuse large B-cell lymphoma with a paracortical growth pattern: a lymphoma of possible interfollicular large B-cell origin.

Context: Activation-induced cytidine deaminase, necessary for immunoglobulin somatic hypermutation and class switch recombination, is usually expressed within the follicular dendritic network but is also expressed in a population of interfollicular large B cells outside the germinal center.

Objective: To report 7 cases of diffuse large B-cell lymphoma with a distinct paracortical distribution. Expression of activation-induced cytidine deaminase, previously described in interfollicular large B cells, was evaluated.

Gene rearrangement and comparative genomic hybridization studies of classic Hodgkin lymphoma expressing T-cell antigens.

Context: Reed-Sternberg cells in classic Hodgkin lymphoma are enigmatic and difficult to study because they are so sparse. Tissue microdissection allows for the isolation of single Reed-Sternberg cells. Isolated Reed-Sternberg cells show clonal immunoglobulin gene rearrangement indicating a B-cell origin.

Histiocytic sarcoma: a study of five cases including the histiocyte marker CD163.

Histiocytic sarcoma (HS) is a rare but controversial hematopoietic neoplasm. In the past, malignancies have been misclassified as histiocytic tumors due to overlapping histologic features and inadequate phenotypic data. CD163, a recently characterized hemoglobin scavenger receptor, appears to be a 'specific' marker of histiocytic lineage and a promising diagnostic tool for evaluating histiocytic neoplasms.