Pulmonary leukemic infiltrations correspond to extravascular collections of leukemic cells in the lung parenchyma. On imaging, although having a broad and nonspecific pattern of presentation, is commonly seen as thickening of the bronchovascular bundles and interlobular septa.
They can be found in the lungs in around 24-64% of patients with leukemia on autopsy. Multiple studies have shown no significant difference in the incidence of the leukemic infiltrates among the four major types of leukemia 6.
The leukemic infiltration is only called by its own, as a direct manifestation of leukemia, in the absence of leukamia-related complications that could be attributed as a cause (eg.: superimposed infection, alveolar hemorrhage, or pulmonary venous congestion) 6.
Histologically, there is atypical lymphocyte infiltration along the interstitium and alveolar spaces.
It can have a variety of nonspecific radiographic appearances.
Most infiltrates do not appear on chest radiographs 1.
Pulmonary consolidations in a variety of patterns have been described, including alveolar, interstitial, mixed, and peribronchial/perivascular patterns 3. There is a general tendency for abnormalities to involve the perilymphatic interstitium 1,6.
Other reported findings include 1,4:
Due to the variable appearance on CT, the differential diagnosis based on imaging may be broad 1:
- 1. Kovalski R, Hansen-Flaschen J, Lodato RF et-al. Localized leukemic pulmonary infiltrates. Diagnosis by bronchoscopy and resolution with therapy. Chest. 1990;97 (3): 674-8. Pubmed citation
- 2. Potenza L, Luppi M, Morselli M et-al. Leukaemic pulmonary infiltrates in adult acute myeloid leukaemia: a high-resolution computerized tomography study. Br. J. Haematol. 2003;120 (6): 1058-61. Pubmed citation
- 3. Heyneman LE, Johkoh T, Ward S et-al. Pulmonary leukemic infiltrates: high-resolution CT findings in 10 patients. AJR Am J Roentgenol. 2000;174 (2): 517-21. doi:10.2214/ajr.174.2.1740517 - Pubmed citation
- 4. Tanaka N, Matsumoto T, Miura G et-al. CT findings of leukemic pulmonary infiltration with pathologic correlation. Eur Radiol. 2002;12 (1): 166-74. doi:10.1007/s003300101013 - Pubmed citation
- 5. Okada F, Ando Y, Kondo Y et-al. Thoracic CT findings of adult T-cell leukemia or lymphoma. AJR Am J Roentgenol. 2004;182 (3): 761-7. doi:10.2214/ajr.182.3.1820761 - Pubmed citation
- 6. Girish S. Shroff, Mylene T. Truong, Brett W. Carter, Marcelo F. Benveniste, Rashmi Kanagal-Shamanna, Greg Rauch, Chitra Viswanathan, Prajwal C. Boddu, Naval Daver, Carol C. Wu. Leukemic Involvement in the Thorax. (2019) RadioGraphics. 39 (1): 44-61. doi:10.1148/rg.2019180069 - Pubmed