Isolated myeloid sarcoma: A unique porta hepatis location in a 2-year-old child

Abstract

Myeloid sarcoma (MS) or chloroma represents extramedullary accumulation of immature myeloid cells. In the World Health Organization classifications, these tumors are called granulocytic sarcomas. MS may occur concomitantly or precede the development of myeloid tumors such as acute myeloblastic leukemia (AML) by several weeks to months. Occasionally, MS represents extramedullary blast transformation of chronic myeloid leukemia and other chronic myeloproliferative neoplasms and myelodysplastic syndromes or indicates relapse in previously treated patients. Immunohistochemistry represents the gold standard of histopathological diagnosis, given the similarity of the MS medium to large-size tumor cells to many other malignant cell infiltrates making them hard to identify. Diagnosis is often difficult to reach and is missed in up to 50% of the isolated MS lesions, especially when immunohistochemistry is not properly used. MS can affect variety of body tissue organs such as the skin, bone, gastrointestinal tract, mucosal tissue, and the central nervous system. Isolated MS of the biliary system is rare. We report a 2-year-old boy with isolated MS affecting the porta hepatis (PH) who responded well to AML-type chemotherapy. Few cases of MS were reported in pediatric patients affecting the liver and biliary system. The development of isolated MS in the PH is extremely rare and has not been previously reported in the literature. To our knowledge, this is the first child to be reported with sole involvement of such location.

Keywords

• granulocytic sarcoma
• isolated myeloid sarcoma
• myeloid sarcoma
• porta hepatis