Pediatric Leukemia

  • Etiology: hematological neoplasm caused by overproduction of immature (blasts) or abnormally differentiated cells of hematopoietic system in bone marrow that often extends into peripheral blood
  • Imaging chest:
    — Mediastinal mass
  • Imaging gastrointestinal:
    — Hepatosplenomegaly due to diffuse infiltration of liver and spleen by leukemic cells
  • Imaging musculoskeletal:
    — Radiograph: 25% of bone lesions visible via radiograph, normal, osteoporosis, metaphyseal lucencies +/- fractures, permeative lesions, aggressive cortical loss, aggressive periosteal reaction, extensive marrow replacement
  • Imaging spine:
    — Radiograph: diffuse osteopenia, loss of vertebral body height (vertebra plana)
    — MRI: diffuse T1 hypointense / T2 hyperintense signal with contrast enhancement (vertebral body marrow should be brighter than the disc on T1), adjacent soft tissue / leptomeningeal disease
  • DDX: metastatic neuroblastoma, Langerhans cell histiocytosis, osteomyelitis, Ewing sarcoma, lymphoma
  • Clinical: abnormal complete blood count, hepatosplenomegaly common at presentation of acute lymphocytic leukemia, most common pediatric malignancy

Radiology Cases of Leukemia

CXR of acute lymphocytic leukemia with infiltration of the thymus
CXR AP+lateral shows a large anterior mediastinal mass centered in the region of the thymus.
CXR and CT of acute lymphocytic leukemia / ALL
CXR AP and lateral (above) shows left hilar and superior mediastinal lymphadenopathy which is better demonstrated on the axial CT with contrast of the chest (below).

Radiology Cases of Splenic Involvement in Leukemia

AXR of acute lymphocytic leukemia
AXR shows diffuse enlargement of the liver and spleen.

Radiology Cases of Chloroma in Leukemia

Radiograph and CT of chloroma in acute myelocytic leukemia
Lateral radiograph of the airway (above) shows a large amount of retropharyngeal soft tissue swelling. Axial CT with contrast of the neck (below) shows a large round low density lesion in the left parapharyngeal space.

Radiology Cases of Bone Involvement in Leukemia

Radiograph of leukemia of the spine
Lateral radiograph of the thoracic spine shows diffuse osteopenia in the vertebral bodies with loss of height (vertebra plana) in all of the vertebral bodies.
Radiograph of acute lymphoblastic leukemia in the spine
Lateral radiographs at presentation of the thoracic (left) and lumbar (middle) spine show diffuse osteopenia and loss of vertebral body height throughout the spine while lateral radiograph obtained a decade later of the lumbar spine (right) shows a faint bone within bone appearance of the vertebral bodies.

Radiology Cases of Typhlitis in Leukemia

CT and US of typhlitis
AXR AP (above left) is unremarkable. Axial CT with contrast of the abdomen (above right) shows moderate thickening of the cecum. Transverse and sagittal US of the cecum (below) shows a moderately thickened cecum lying above the right psoas muscle.