Peripheral lobular accentuation
Peripheral lobular accentuation

UIP is a pattern of lung fibrosis that typically shows peripheral lobular accentuation, as demonstrated in this image. Fibrosis tends to outline lobules, producing a "donut-like" ring around more normal lung centrally in the lobule (C = lobule center). Note the presence of normal lung, a hallmark of this form of pulmonary fibrosis. As the disease progresses microscopically, normal lung is lost and the result is advanced honeycomb remodeling. When honeycombing is the only feature present, the biopsy cannot accurately predict the presence of UIP.