A B-cell "chameleon": striking clinical, morphological, and immunophenotypic diversity of a single low-grade B cell clone.

A patient with an 18-year history of low-grade B-cell lymphoproliferative disorders is presented. Although the precise classification of these B-cell disorders was problematic, the blood, bone marrow, spleen, lymph node, and gastrointestinal lesions evaluated were compatible morphologically with such apparently disparate diagnoses as hairy cell leukemia, marginal zone lymphoma, mantle cell lymphoma, and gastrointestinal multiple lymphomatous polyposis. Although each low-grade disease that developed over an 18-year interval was clinically, morphologically, and immunophenotypically distinct, genotyping showed their derivation from a single B cell clone. This case emphasizes that a single B-cell clone may give rise to several distinct low-grade B-cell lymphoproliferative disorders with diverse clinical and pathological features.