Paravertebral extramedullary haematopoiesis mimicking myeloid sarcoma

Abstract

Abstract Extramedullary haematopoiesis (EMH) is the formation and development of blood cells outside the bone marrow. They are benign process associated with myeloproliferative disorders, haemolytic anaemia, hereditary spherocytosis and Gaucher’s disease. The common locations for EMH are reticuloendothelial system, namely liver, spleen and lymph node. However, other locations such as lung, urogenital system, retroperitoneum and mediastinum are rare sites of occurrence. A 50-year-old male, with sickle cell disease, presented with a history of dyspnoea and backache showing a bilateral mass in the paravertebral (thoracic) region, pleural thickening and small mass in the lung. The clinical diagnosis was lung neoplasm. The needle core biopsy was obtained from the paravertebral mass. Microscopy showed trilineage haemopoietic proliferation along with few fat cells. Thus, the diagnosis of EMH was made. Being a rare benign entity, EMH often mimics malignancy as well as granulocytic sarcoma which show the presence of acute or chronic leukaemia, presence of increased eosinophilic precursor and increased number of myeloblasts. Thus, the awareness of the entity as well as early diagnosis helps the patient in appropriate management of this benign yet rare entity.