Minimally invasive adenocarcinoma of the lung

Case contributed by Dr Bruno Di Muzio

Patient Data

Age: 50 years
Gender: Female
CT

CT Chest (3 years ago)

There is an ill-defined focal ground-glass opacity in the superior segment of the right lower lobe measuring approximately 5 mm in diameter. A few scattered pulmonary nodules measuring up to 6 mm in diameter. Lungs are otherwise unremarkable. No mediastinal lymphadenopathy. 

CT

CT Chest (1 year ago)

The focal ground-glass opacity in the superior segment of the right lower lobe has increased, measuring 9 mm in diameter. The remaining pulmonary nodules are unchanged. Lungs are otherwise unremarkable. No mediastinal lymphadenopathy. 

CT

CT Chest (current)

The focal ground-glass opacity in the superior segment of the right lower lobe has increased, measuring 12 mm in diameter. The remaining pulmonary nodules are unchanged. Lungs are otherwise unremarkable. No mediastinal lymphadenopathy. 

Annotated image

Diagram showing the slow growth of the ground glass opacity over a three-year period.

Nuclear medicine

PET-CT (18F-FDG)

No FDG uptake within the focal ground-glass opacity in the superior segment of the right lower lobe.

Macroscopy: Labelled "Right lower lobe". Right lower lobe weighing 121 g measuring 158 x 125 x 90 mm. Pleura appears pale tan/brown and grey with a smooth texture. Stapled margin inked green and hilum black and sectioned from superior to inferior into 13 slices. Within slices 3 and 4 there is a subpleural firm cream lesion measuring 12 x 8 x 5 mm. Lesion is 15 mm clear of the stapled margin and greater than 20 mm from the hilar margin. There is no invasion into large airways or vessels. There is no extension through the pleural surface. Pleura is inked blue at area of lesion. 3 potential lymph nodes ranging from 3–5 mm appear carbon pigmented. The remainder of parenchyma appears brown/tan. No thrombi are identified. 

Microscopy:  Sections through the pulmonary parenchyma show an 8 mm lesion within which a population of atypical non-mucinous epithelial cells show a predominantly lepidic pattern of growth. The cells have enlarged, hyperchromatic, ovoid nuclei with moderate amounts of eosinophilic cytoplasm showing a hobnail appearance. The cells are arranged in pseudostratified files over alveolar septa. Centrally, over less than 5 mm in linear extent, the tumour shows papillary and acinar growth patterns. The lesion is confined to the pulmonary parenchyma, showing no extension through the pleura, and lies clear of parenchymal resection margins. Angiolymphatic invasion is not identified. Anthracotic hilar lymph nodes show no evidence of metastatic malignancy.

Diagnosis: Right lower lobectomy specimen: Minimally invasive adenocarcinoma, non-mucinous, of lung.

  • 8 mm in maximum dimension
  • lepidic pattern predominant
  • secondary papillary and acinar patterns, no more than 5 mm in maximum extent
  • no necrosis
  • no angiolymphatic invasion
  • no pleural invasion
  • clear of margins
  • no malignancy in four hilar lymph nodes

Case Discussion

This case illustrates a slowly growing focal lung lesion, confirmed to represent a minimally invasive lung adenocarcinoma (MIA), staged as T1aN0M0.  

MIA represents one of the categories of the previously known bronchioloalveolar carcinoma (BAC). It is a small lepidic tumor with an invasive component of 5 mm or smaller.

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Case information

rID: 59351
Published: 7th Apr 2018
Last edited: 7th Apr 2018
System: Chest
Inclusion in quiz mode: Included

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