Contribution of Cytology to the Diagnosis of Chediak-Higashi Syndrome.

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by partial oculocutaneous albinism, recurrent infections, and giant intracytoplasmic granules in leukocytes. Early diagnosis is critical to prevent the onset of severe complications, particularly the accelerated phase. We conducted a descriptive case series in the Hematology Laboratory of Ibn Rochd University Hospital Center, Casablanca. All patients diagnosed with CHS based on cytological analysis were included. Complete blood counts were performed using the SYSMEX® XN-1500 analyzer (Sysmex Corporation, Kobe, Japan), and peripheral blood and bone marrow smears were stained with May-Grünwald Giemsa. Five patients (three girls and two boys) were identified, with a mean age of four years and 11 months. Parental consanguinity was present in all cases. Clinical findings included oculocutaneous albinism (n=4), splenomegaly (n=4), lymphadenopathy (n=3), and recurrent bacterial infections (n=4). Cytological analysis revealed pathognomonic giant granules within granulocytes in all patients. All patients developed hemophagocytic lymphohistiocytosis and succumbed to disease-related complications. In resource-limited settings, cytological evaluation remains a crucial tool for diagnosing CHS when genetic testing is unavailable. Early identification of suggestive clinical features, combined with cytological findings, can facilitate prompt diagnosis and timely initiation of appropriate management, including hematopoietic stem cell transplantation, the only curative treatment available.