Transbronchial biopsy in usual interstitial pneumonia

Abstract

Background: Usual interstitial pneumonia (UIP) is a slowly progressive, usually fatal form of idiopathic interstitial pneumonia for which there is no effective treatment. Transbronchial biopsy (TBB) has been utilized only to exclude other diseases such as sarcoidosis, lymphangitic carcinoma, and infection, for example, but TBB is generally considered to have little role in confirming UIP.

Objective: To determine whether diagnostic changes of UIP can be appreciated on TBB specimens.

Design: Retrospective analysis of TBB specimens from patients with proven UIP.

Setting: Two study sites in the United States.

Participants: Twenty-one patients with UIP confirmed by surgical lung biopsy and/or lung explant, and 1 patient with UIP confirmed by clinical and radiographic findings along with follow-up information.

Measurements and results: Adequate tissue for diagnosis was available in 18 cases; in 7 cases (32% overall), there were varying combinations of interstitial fibrosis in a patchwork pattern along with fibroblast foci and/or honeycomb change. These features were considered diagnostic of UIP. Interstitial fibrosis along with fibroblast foci or honeycomb change were seen in two other cases, but the fibrosis lacked a patchwork pattern, and these features were considered consistent with UIP. Nonspecific interstitial fibrosis alone was found in nine cases.

Conclusions: In summary, characteristic histologic features of UIP can be identified on TBB specimens more often than previously appreciated. TBB may be more useful in confirming UIP than previously recognized.

FIGURE 1

Case 2. Left, A: Low-magnification photomicrograph showing the characteristic patchwork pattern of fibrosis in UIP. Note the relatively normal lung in the center adjacent to marked interstitial fibrosis in surrounding parenchyma (hematoxylin-eosin, original × 10). Center, B: Low-magnification view showing honeycomb change in another fragment characterized by enlarged, irregular air spaces filled with mucin (hematoxylin-eosin, original × 10). Right, C: Higher-magnification view showing a fibroblast focus. Note the interstitial location of spindle-shaped cells embedded in a myxoid background. The surrounding lung parenchyma shows collagen-type fibrosis and mild chronic inflammation (hematoxylin-eosin, original × 20).

FIGURE 2

Case 22. Left, A: Low-magnification photomicrograph showing variegated fibrosis (hematoxylin-eosin, original × 10). Note the patchwork pattern of involvement with areas of interstitial fibrosis alternating with normal lung. Right, B. Higher-magnification view of a fibroblast focus present in the central upper portion on left, A, showing interstitial location and characteristic lightly stained myxoid stroma containing spindle-shaped cells (hematoxylin-eosin, original × 20).

FIGURE 3

Case 14. Low-magnification photomicrograph of honeycomb change. The airspaces are enlarged, deformed, irregularly shaped, and lined by bronchial type epithelium (hematoxylin-eosin, original × 10).

FIGURE 4

Case 16. Prominent fibroblast foci in a background of interstitial collagen-type fibrosis. Fibroblast foci are recognized by their myxoid appearance, with spindle-shaped cells arranged parallel to the alveolar lining (hematoxylin-eosin, original × 10).