It was described a case of chronic lymphocytic leukemia in a 75 year old man, with pseudoyelomatous osteolytic lesions in the skull, excluding other potential causes of osteolytic lesions in the clinical context of malignant lymphoproliferative neoplasms. The real frecuency of osseous compromise in chronic lymphocytic leukemia is 10%. Lesions are defined as generalized osteoporosis and osteolisis with lacunar aspect, similar to myeloma lesions. Because histopathology in lymphoproliferative neoplasms may be similar, it might be difficult to diagnose chronic lymphocytic leukemia certainly, if the clinical manifestations are not considered. Difterential diagnosis with other lymphoproliferative neoplasms is based basically in absolute lymphocytosis greater than 10 X 109/L, with lymphocytes with mature appearance.