[Granulocytic sarcoma with mediastinal involvement].

Background: Granulocytic sarcoma is more frequent in adults; it can be a tumoral localization of acute non-lymphoblastic leukemia. This report describes an infantile case revealing an acute myeloid leukemia.

Case report: A 14 month-old girl was admitted because of enlarged bilateral cervical lymph nodes. They had increased in volume over the past month and were accompanied by fever and anorexia. The liver and spleen were moderately enlarged. Hematologic data were: Hb = 7.5 g%; leucocytes = 14,900/mm3; platelets = 614,000/mm3. There were no abnormal cells. X-rays and MRI showed a mediastinal mass. Bone scintigraphy was normal but the myelogram showed a few atypical cells that were also seen in a biopsy of the cervical lymph node. Electron microscopic examination of these cells showed that they were myeloid in origin. This was confirmed by immunohistochemistry. The cytogenetic examination showed many chromosomal abnormalities in the lymph node and myelogram. The child is now recovered after nine months of chemotherapy.

Conclusion: Diagnosis of acute myeloblastic leukemia in children is difficult when it is revealed by granulocytic sarcoma without major infiltration of bone marrow. The clinical presentation as a mediastinal mass is rare. The cytogenetic study was determinant for diagnosis.