E2854. Imaging of Early Lung Cancer and Its Precursor Lesions
  1. Eric Hexem; University of Missouri
  2. Cody Thornburgh; University of Missouri
  3. Jeffrey Kunin; University of Missouri
  4. Mohamed Ebada; University of Missouri
  5. Lucia Flors; University of Missouri
  6. Christopher Walker; University of Kansas
Lung cancer is the most common cancer worldwide. Furthermore, adenocarcinoma is the most common subtype of lung cancer and accounts for 40% of all lung cancers diagnosed annually in the United States. Early detection and treatment of adenocarcinoma is therefore a high priority from a public health standpoint. It has been postulated that precursors to invasive adenocarcinoma may exist in discrete and characteristic forms. We present the spectrum of lung adenocarcinoma with its earliest precursor lesion atypical adenomatous hyperplasia (AAH). We then demonstrate how a portion of these lesions progress to adenocarcinoma-in-situ (AIS), minimally invasive adenocarcinoma (MIA), and, finally, invasive adenocarcinoma (IAC).

Educational Goals / Teaching Points
Define AAH as a possible premalignant early precursor to adenocarcinoma and demonstrate its imaging findings. Define AIS as a preinvasive form of adenocarcinoma and demonstrate its imaging findings. Define MIA as an early invasive form of adenocarcinoma and demonstrate its imaging findings. Correlate histopathology with imaging findings of AAH, AIS, and MIA. Describe imaging pitfalls and challenges of AAH, AIS, and MIA. Review management of lesions suspected to be a precursor or early form of lung adenocarcinoma.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Early invasive lung cancer and its precursors have a characteristic but varied imaging appearance on CT and may be confused with other benign and malignant entities. We discuss how ground-glass nodules and part-solid nodules correlate with early lung cancer. We also address the role, if any, imaging-guided biopsies and PET imaging play in the management of these patients.

Invasive lung adenocarcinoma constitutes the end point of a continuum of neoplastic parenchymal proliferation, beginning as precancerous foci of AAH and progress through AIS, MIA, and IAC. The reliable detection of early lesions may assist in the management of adenocarcinoma precursors prior to the invasive stage.