Successful treatment of extranodal Hodgkin's lymphoma in a patient with longstanding hairy cell leukemia

Purine analogs, particularly pentostatin and cladribine, are highly effective in hairy cell leukemia (HCL). Both of these drugs induce responses in approximately 80 - 95% of patients. However, it is not yet determined if treatment with these drugs can induce second malignancies. Hodgkin's lymphoma is very rare as a second malignancy and there are only 3 reported cases concerning the association of this lymphoma with HCL. We describe a patient with longstanding HCL in complete remission after cladribine, in whom extranodal Hodgkin's lymphoma appeared 8 years after the diagnosis of HCL. Magnetic resonance imaging revealed diffuse intra-osseal neoplastic infiltration of the corpora of the whole spinal column and extra-osseal propagation from the fifth thoracic vertebra into the spinal canal with spinal cord compression. Histological and immunohistochemical analysis of the extradural tumor, which was completely excised, disclosed nodular sclerosis Hodgkin's lymphoma with typical Reed - Sternberg cells that were positive for CD30, CD15, bcl-6, Ki67, p53, EBV LPM-1 and IgG, and negative for CD45, CD20, DBA44, kappa, lambda light chains and IgM. In addition, immunohistochemical analysis of the bone marrow in 1999 showed infiltration with positivity for IgM and negative for kappa light chains and IgG. These findings (expression of different immunoglobulins and light chains on the cells) suggest an independent origin of these 2 B-cell neoplasms. After neurosurgery the patient received 6 courses of the MP-ABVD protocol and achieved a complete remission, which has lasted 16 months thus far.