The value of bone marrow biopsy in the prognosis of hairy cell leukemia (HCL).

Histological findings in the bone marrow and their changes in the course of the disease and therapy were evaluated with respect to the prognosis in a group of 32 patients with hairy cell leukemia (HCL). Two types of bone marrow infiltration by hairy cells (HCs), the diffuse type and the interstitial type, respectively were found. The diffuse type of infiltration and the minimal or absent residual hematopoiesis (RH) at presentation were found with statistical significance to be unfavorable prognostic findings when compared with interstitial infiltration and persisting RH (p < 0.01). Reticulin fibrosis is a characteristic finding in HCL and was found in all but 2 patients.