Loss of hearing is a rare complication of chronic myeloid leukaemia.' 2 We describe the occurrence of varying degrees of impairment of hearing in nine out of 44 Nigerian patients with the disease. Patients, methods, and resultsChronic myeloid leukaemia was diagnosed in the usual way based on clinical and laboratory findings including total and differential white cell counts. Cytogenetic analysis was not routinely available. The diagnosis of hearing disorders was based on the history given by the patient as well as on findings of routine physical examination. In addition, audiometric studies were performed when indicated, and these were repeated at intervals when possible. In order to evaluate the influence of anaemia and severity of hyperleucocytosis at the time of occurrence of hearing impairment, each patient with an auditory complication of chronic myeloid leukaemia was matched according to age, sex, and state of the disease-that is, whether in a "steady" or accelerated phase-with control patients suffering from the disease but who did not have clinical evidence of a hearing problem. Relevant laboratory data were compared by the usual statistical methods.Eight of the nine patients with auditory problems were clinically and haematologically in the chronic phase of their disease at the time that the problem occurred. Comparison of the packed cell volumes and white cell counits of these patients (table) with those of the controls showed no significant difference in median packed cell volumes (0-24 v 0 33; p >0 05) but a significantly higher median white cell count in the group with impaired hearing (434 Ox 109/1 v 257-Ox 10' 1; p<0 05). Three of the five patients with moderate hearing impairment who were followed up long enough during chemotherapy showed a remarkable subjective improvement in hearing associated with a reduction in the peripheral white cell count to the range 10 0-20 0x 1091; in the remaining four patients, however (cases 2, 5, 6, 7), profound deafness persisted despite similar satisfactory haematological control. CommentWe have described auditory disturbances ranging in severity from mild to profound loss of hearing occurring in nine of 44 Nigerian patients with chronic myeloid leukaemia who presented either at an advanced stage or after prolonged lack of control of the disease.It appears most likely that the uniformly associated high degree of leucocytosis (table) is a major predisposing factor in the pathogenesis of this complication. The role of severe anaemia, which was present in six of our patients (table), is less clear. Hyperleucocytosis may lead to the formation of leucocyte thrombi and failure of the microvasculature,3 which for unknown reasons manifested in our patients as auditory impairment and also as cerebellar ataxia (case 2), priapism (case 4), and "organic brain syndrome" (case 7). The central role of the physical characteristics of the leucocytes4 concerned in the leucostasis is underscored by the fact that none of 34 patients with chronic lymphocytic leukaemia who had white...

SummaryThe case is described of an eight-year-old Nigerian boy who died from olfactory neuroblastoma which presented with nasal obstruction and epistaxis. Autopsy showed intracranial extension of the tumour into the frontal lobe, and histology revealed undifferentiated neuroblasts, forming rosette in some areas and producing tangled neurofibrils in others. The histogenesis of the tumour and its diagnosis are briefly discussed.