PMC7575649_01
(A, B, C) Chest computed tomography. Left lower lung shows a 6-cm-diameter pure ground-glass opacity. (D) Positron emission tomography/computed tomography. The left lower lung mass shows an unremarkable uptake of 18F-fluorodeoxyglucose; the early maximum standardised uptake value of the mass was 1.9.
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Chest thin-slice computed tomography (TSCT) showed a 6-cm-diameter pure ground-glass nodule (GGN) in the left lower lung (Fig. 1A-C). Positron emission tomography/computed tomography showed that the mass had an unremarkable uptake of 18F-fluorodeoxyglucose, with an early maximum standardised uptake value of 1.9 (Fig. 1D). Mitotic figures were rare, and the MIB-1 index was 2%.
Histological findings. (A, B) Grossly, the tumour is widely distributed to the dorsal region of the inferior lobe and measures 6 cm in diameter without central scarring or pleural indentation. The delicate lace-like cut-surface suggests well-preserved alveolar structures. (C) Microscopically, the neoplastic cells proliferate in a single layer along pre-existing alveolar structures (lepidic growth), lacking stromal invasion or papillary growth in the low-power view. Tumour cells are columnar with uniform-sized round to ovoid nuclei. Nuclear atypia is inconspicuous. (Haematoxylin and eosin: x10).
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Tumour sections had a delicate lace-like appearance with no central scar or pleural depression (Fig. 2). Mitotic figures were rare, and the MIB-1 index was 2%. The final pathological diagnosis was LPA lacking an invasive component (Fig. 2).