The differential diagnosis of the B-cell lymphoproliferative disorders can sometimes by tricky. When the morphology and flow cytometric studies are classic, the case should not present a diagnostic challenge. However, when the lesion does not read the book, one must take into consideration the morphology/cytology, flow cytometry, and clinical history. Integrating all three of these will often lead to the correct diagnosis; however, there will be occasional cases where the best that a pathologist can say is "B-cell lymphoproliferative disorder". In those instances, one should not overcall something, but rather should state what the problems are, and what are most likely to be the diagnostic possibilities.