Atypical prolymphocytic variant of hairy-cell leukemia: case report and review of the literature.

The prolymphocytic variant of hairy-cell leukemia (HCL-V) is relatively rare and differs from typical hairy-cell leukemia (HCL) both clinically and morphologically. Recognition of HCL-V is important due to therapeutic impact. We report on a case of HCL-V, atypical in its degree of marrow fibrosis, IgM/lambda monoclonality, expression of CD24, and the ultrastructural presence of ribosomal lamellar complexes. The patient was treated with splenectomy followed by pentostatin, and he achieved a partial response.