A myeloid sarcoma (MS) is an extramedullary tumor consisting of primitive granulocytic precursor cells. Although most such tumors have been reported in patients with acute myelogenous leukemia, MS is rarely recognized as an isolated tumor without any evidence of leukemia. However, in such cases, the initial diagnosis of MS can be difficult, so initial misdiagnosis rates of up to 75% have been reported. This report describes an unusual case of MS in a 3-year 5-month-old girl presenting as bilateral renal enlargements, and brain masses, with multiple bone involvements, but no hematological abnormalities.
Bone Neoplasms/pathology/*radiography ; Brain Neoplasms/pathology/*radiography ; Child, Preschool ; Female ; Human ; Kidney Neoplasms/pathology/*radiography ; Sarcoma, Granulocytic/pathology/*radiography ; Tomography, X-Ray Computed

Granulocytic sarcoma (GS) is an extramedullary tumor composed of immature myeloid cells, typically occurring during the course of acute myelogenous leukemia. Non-leukemic GS, that is, GS with no evidence of overt leukemia and no previous history of leukemia, is very rare, and even more unusual is nonleukemic GS of the bile duct. We report a case of nonleukemic GS of the bile duct. The patient was initially misdiagnosed as a bile duct carcinoma arising in the hilum of the liver (so-called Klatskin tumor), and received a right lobectomy of the liver. Histological examination of the tumor yielded the diagnosis of GS, and the bone marrow biopsy did not show any evidence of leukemia. Considering the risk of subsequent development of overt leukemia, the patient was treated with two cycles of combination chemotherapy as used in the cases of acute myelogenous leukemia. To date, he has remained free of disease 15 months after treatment.
Tomography, X-Ray Computed/methods ; Sarcoma, Granulocytic/*diagnosis/metabolism/radiography ; Radiography, Abdominal ; Peroxidase/analysis ; Male ; Immunohistochemistry ; Humans ; Diagnosis, Differential ; Bile Ducts/chemistry/pathology ; Bile Duct Neoplasms/*chemically induced/metabolism/radiography ; Antigens, CD45/analysis ; Adult