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Age / Sex : 9 / M
Age/Sex: 9/M
C.C.: Left knee pain (onset: 1 month),
Mild fever (37.5`)
Lab: leucytosis (12,700), Anemia, ESR, CRP elevation
Past History: negative
1) What is your impression?
Courtesy : Cheol Mog Hwang, MD., Konyang University Hospital
Diagnosis: leukemia (chloroma)
Discussion
Findings:
1. Simple radiography : - Subtle geographic osteolytic lesion without peripheral sclerotic lesion at distal metaphysis of left distal femur
2. MR : - On T1-weighted axial and sagittal images, the lesion is non visualized. - On T2 and proton-densited image, the lesion is ill-defined heterogeneous high signal intensity lesion. - On T1-weighted contrast enhanced images, the lesion is irregular heterogeneous enhanced.
Differential Diagnosis:
1) Osteomyelitis 2) Ewing’s sarcoma 3) Leukemia or lymphoma Diagnosis: Leukemia (chloroma)
Discussion:
1. Introduction ① Most common malignancy of childhood: ALL(75%), AML(15-20%), CML(5%) ② Etiology External factors: Alkylating drugs, ionizing radiation, chemicals(benzene) Internal factors: Chromosomal abnormalities Predisposing hematologic disorders: Aplastic anemia, chronic myeloproliferative disorders ③ Neoplastic disorder of white blood cells than can be myeloid or lymphoid in origin and acute or chronic ④ Granulocytic sarcoma(chloroma) represents extramedullary tumor of immature granulocytic cells in association with leukemia 2. Location ① Children: Femur (24%), Humerus(11%), Ilium(17%), Spine(14%), Tibia(9%), Scapula(4%) ② Adults: Axial skeleton
3. Image findings ① Simple radiography: Moth eaten bone destruction +/- radiolucent transverse metaphyseal bands(leukemic lines) Diffuse osteopenia of spine and long bones Focal destruction of flat/tubular bones Periostitis of long bones:12-25% Pathologic fracture ② CT: Permeative bone destruction Helpful in demonstrating localized mass in case of granulocytic sarcoma ③ MR: T1WI: Leukemic infiltrate of low signal, replacing high signal marrow fat T2WI: Increased signal intensity of leukemic marrow STIR: Increased signal intensity of leukemic marrow Most sensitive imaging modality, often positive when radiographs show no abnormalities
4. Differential diagnosis ① Metastases ② Langerhans Cell Histiocytosis(LCH) ③ Osteomyelitis ④ Ewing’s Sarcoma ⑤ Lymphoma
5. Treatment ① Chemotherapy Induction phase, consolidation phase, maintenance therapy phase Intrathecal chemotherapy in case of CNS involvement ② Combinesd chemo- and radiation therapy ③ Bone marrow transplant
References:
1. Gallagher DJ et al, Orthopedic manifestation of acute pediatric leukemia. Orthop Clin North Am 1996:27;635-44
2. Stoller DW et al, Diagnostic Imaging, orthopaedics. Utah, Amirsys Inc, 2004:7;10-13
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