Elementary Lesions
Patchwork pattern
Characteristics
Disseminated, non uniform patchwork pattern of interstitial fibrosis
Non-uniform, heterogeneous appearance with alternation between abnormal fibrotic areas and apparently normal lung parenchyma at low-magnification.
The juxtaposition of abnormal areas and normal areas resembles a patchwork, hence the term “patchy”.
Diagnostic Orientation
Topographic diagnosis at low-magnification
Fibrosis
easily identifiable by the saffron in HES (Hemalum-EosinSaffron)
on special staining like trichrome
1. Patchwork pattern
2. Characteristic patchwork pattern
3. Characteristic patchwork pattern
4. Less typical distribution of fibrosis: absence of normal nonfibrotic parenchyma
5. Less typical distribution of fibrosis: absence of normal nonfibrotic parenchyma
