Lung

Adenocarcinoma

Minimally invasive


Editor-in-Chief: Debra L. Zynger, M.D.
Jonathan Keow, M.D., Ph.D.
Matthew J. Cecchini, M.D., Ph.D.

Topic Completed: 22 February 2021

Minor changes: 22 February 2021

Copyright: 2019-2021, PathologyOutlines.com, Inc.

PubMed Search: Adenocarcinoma minimally invasive [TI] lung

Jonathan Keow, M.D., Ph.D.
Matthew J. Cecchini, M.D., Ph.D.
Page views in 2020: 493
Page views in 2021 to date: 2,076
Cite this page: Keow J, Cecchini MJ. Minimally invasive. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungtumoradenominimallyinvasive.html. Accessed October 24th, 2021.
Definition / general
Essential features
  • Tumor with noninvasive (lepidic) and invasive components
  • Total tumor size must be less than 3 cm
  • Invasive or nonlepidic components must be less than 0.5 cm
  • Invasive component can be of any subtype other than lepidic
  • No lymphovascular invasion, tumor necrosis or pleural invasion is present
  • Usually nonmucinous but can rarely occur in mucinous tumors
Terminology
  • Minimally invasive adenocarcinoma (MIA)
  • Microinvasive adenocarcinoma
  • Older terminology used: bronchoalveolar carcinoma; however, this is obsolete and should no longer be utilized
ICD coding
  • ICD-O: 8250/2 - minimally invasive adenocarcinoma, nonmucinous (international code)
  • ICD-O: 8257/3 - minimally invasive adenocarcinoma, mucinous (international code)
  • ICD-10: C34.9 - malignant neoplasm of unspecified part of unspecified bronchus or lung
  • ICD-11: XH3QM0 - minimally invasive adenocarcinoma, nonmucinous
  • ICD-11: XH2098 - minimally invasive adenocarcinoma, mucinous
Epidemiology
Sites
Pathophysiology
Etiology
Clinical features
Diagnosis
Radiology description
Radiology images

Images hosted on other servers:
Ground glass lesion on CT scan

Ground glass lesion on CT scan

Prognostic factors
Case reports
Treatment
Gross description
  • Peripheral, ill defined, firm, white tumor with solid areas; ill defined areas correspond to lepidic growth pattern and solid areas correspond to invasive component (Hum Pathol 2016;51:41)
  • Necrosis and frank pleural invasion should be absent
Gross images

Contributed by Sarah Aziz, M.D.
Lobectomy specimen

Lobectomy specimen

Microscopic (histologic) description
  • Primary lung adenocarcinoma measuring ≤ 3 cm in greatest dimension, with ≤ 0.5 cm area of either stromal invasion or nonlepidic growth pattern (acinar, micropapillary, papillary, solid, colloid, fetal or invasive mucinous patterns)
  • Foci of stromal invasion characterized by angulated glands, desmoplastic stroma and increased cytologic atypia (Cancer 1995;75:2844)
  • Size of invasion should be measured as the largest focus of invasion (Am J Surg Pathol 2014;38:448, Arch Pathol Lab Med 2013;137:685)
  • If there are multiple foci of invasion, the invasive size can be measured as a sum of the percentage of the invasive components in each section multiplied against the greatest tumor dimension (the aggregate invasive size should be ≤ 0.5 cm to render the diagnosis of a minimally invasive adenocarcinoma) (Am J Surg Pathol 2014;38:448, Surg Today 2019;49:828)
  • Necrosis, lymphovascular invasion, pleural invasion and spread through air spaces must be absent
Microscopic (histologic) images

Contributed by Jonathan Keow, M.D., Ph.D.
Noninvasive and invasive components

Noninvasive and invasive components

Noninvasive lepidic adenocarcinoma

Noninvasive lepidic adenocarcinoma

Focus of invasive adenocarcinoma

Focus of invasive adenocarcinoma

Negative stains
Sample pathology report
  • Lung, right lower lobe, lobectomy:
    • Minimally invasive adenocarcinoma, pT1mi NX MX (see synoptic report)
Differential diagnosis
Additional references
Board review style question #1
Which of the following tumors would be classified as a minimally invasive adenocarcinoma?

  1. 2 cm lepidic predominant tumor with a 0.8 cm invasive component
  2. 2 cm lepidic predominant tumor with a 0.4 cm invasive component
  3. 2 cm lepidic predominant tumor with a 0.4 cm invasive component with pleural and lymphovascular invasion
  4. 5 cm lepidic predominant tumor with a 0.4 cm invasive component
Board review style answer #1
B. 2 cm lepidic predominant tumor with a 0.4 cm invasive component

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Reference: Adenocarcinoma - minimally invasive
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