Introduction: Chronic myeloid leukemia (CML) is a clonal malignancy arising from the hemopoeitic stem cell (HSC). The disease can be complicated by hyperleucocytosis which is a medical emergency associated with high mortality of about 20–40%, and can results in various complication including tumour lysis syndrome, disseminated intravascular coagulation and leucostasis. The common sites for leucostasis are the lungs and central nervous system.
Case Report: We report a 15-year-old girl presented with one month history of progressive headache, fever, night sweat and one week history of right facial deviation and drooping of the left eyelid. Examination revealed hepatosplenomegaly and right infra nuclear seventh palsy. Complete blood count revealed hyperleucocytosis, with total white cell count (WCC) of > 275 109/l. Peripheral blood film and bone marrow cytology were in keeping with CML in chronic phase. Real time polymerase chain reaction analysis of whole blood was positive for Philadelphia chromosome. Cytoreductive treatment with hydroxyurea was started immediately following initial supportive treatment to prevent tumor lysis syndrome. Progressive improvement in both clinical and laboratory parameters was achieved, however, the patient still had residual facial palsy at third month follow-up.
Conclusion: This is a rare case of hyperleucocytic chronic myeloid leukemia complicated by infra nuclear seventh palsy at the initial presentation. There was partial response to cytoreduction using hydroxyurea.

Keywords: Chronic myeloid leukemia, Hyperleukocytosis, Facial nerve palsy