CT classification of acute myeloid leukemia with pulmonary infiltration

Purpose: To characterize and categorize the CT findings of pulmonary leukemic infiltration (PLI) in patients with acute myeloid leukemia (AML).

Materials and methods: Among 435 patients with AML, 20 patients with PLI were retrospectively selected, and clinical characteristics and CT findings were analyzed. PLI was categorized into four patterns according to CT findings: type A, multiple nodules and/or masses; type B, bilateral perihilar airspace opacities (GGA or consolidation) without any nodules or masses; type C, mixture of type A and B; and type D, PLI without visible abnormal lung opacity. The difference in overall survival among four CT patterns was also examined.

Results: The frequency of complex karyotypes was higher in AML patients with PLI than in whole AML patients. Percentages of patients with CT findings of type A, B, C, and D were 35%, 20%, 35%, and 10%, respectively. There was a clear difference in the localization of opacities according to the type of infiltrates, i.e., nodules/masses were mainly detected in the lower/peripheral portion. Conversely, GGA was mainly located in the upper/central portion. The median overall survival from diagnosis of PLI was 262 days (range 12-1148). The CT pattern was not significantly associated with survival (p = 0.3), with the exception of patients with type C tending to have significantly better outcomes compared to patients with type B (p = 0.05).

Conclusion: This classification can contribute in accurate non-invasive diagnosis and possibly in the estimation of prognosis.