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Lung tumor

Other carcinoma

Bronchioloalveolar carcinoma

Reviewer: Deepali Jain, M.D. (see Reviewers page)
Revised: 8 April 2014, last major update September 2012
Copyright: (c) 2003-2013, PathologyOutlines.com, Inc.


● Refers to growth pattern called lepidic, which arises from and spreads along alveolar walls without invasion
● Similar to jagziekte, a disease of South African sheep, but jagziekte DNA not identified in human tumors
● IASLC/ATS/ERS classification (Mod Pathol 2011;24:653): BAC no longer a valid diagnosis
● WHO definition: adenocarcinoma with bronchioloalveolar pattern and no evidence of stromal, vascular, or pleural invasion, based on complete resection specimen

Bronchioloalveolar carcinoma: how to classify tumors now

1. <=3cm, NO stromal, lymphatic, vascular or pleural invasion, no necrosis, no growth patterns other than lepidic:
● Adenocarcinoma in situ, either serous or mucinous

2. <=3cm, with <=5mm area of stromal invasion or growth pattern(s) other than lepidic:
● Minimally Invasive Adenocarcinoma (MIA)

3. >3cm OR lymphatic, vascular or pleural invasion OR necrosis OR >5mm area of stromal invasion OR growth pattern(s) other than lepidic:
● Serous: invasive adenocarcinoma, lepidic predominant or
● Mucinous: invasive mucinous adenocarcinoma

● Invasion defined as histological subtypes other than lepidic or presence of a myofibroblastic stroma associated invasive tumor
● For tumors with multiple foci, measure largest dimension on a single slide; do NOT sum invasive foci on all slides

Micro images


Mucinous: H&E, TTF1, CK7, CK20

Nonmucinous (H&E, TTF1, CK7, CK20)

Bronchioloalveolar cell adenocarcinoma of the lung

Carcinoma in situ arising in bronchiolar metaplasia co-existing with invasive adenocarcinoma

End of Lung tumor > Other carcinoma > Bronchioloalveolar carcinoma

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