Unusual clivus lesion demonstrating extramedullary haematopoiesis: case report

INTRODUCTION: An unusual clivus mass is reported, following investigation of memory disturbance and headaches in a patient with beta thalassaemia and sickle cell disease. This lesion proved to be a site of extramedullary haematopoiesis. RADIOLOGICAL FINDINGS: Computed tomography demonstrated a 2 cm mass at the base of the sphenoid. However, magnetic resonance imaging showed little bony expansion, and the differential diagnosis included chordoma, dermoid cyst and fibrodysplasia. HISTOLOGICAL FINDINGS: Examination of the biopsy showed the presence of bone marrow demonstrating erythroid hyperplasia and small aggregates of B-cell lymphocytes. The features were considered compatible with erythroid hyperplasia associated with haemolytic anaemia. MANAGEMENT: The patient was reassured that she did not have a neoplastic lesion, and was referred back to the haematologists for further management of her sickling beta thalassaemia. CONCLUSIONS: Extramedullary haematopoiesis occurs outside the reticuloendothelial system in response to haemolytic anaemia. Extramedullary haematopoiesis causing a clivus mass is an unusual ENT presentation. Such haematopoiesis is occasionally seen in the calvarial skull, but this is the first report of this process occurring in the anterior skull base, to our knowledge.