Presentation
45 pack-year smoking history with 3 years of progressive dyspnea. Pulmonary function tests demonstrated a restrictive pattern.
Patient Data
Chest radiographs show only mild upper lobe fibrosis, most evident on the right. Mild left lower lobe atelectasis is also seen.
Chest CT shows mild interlobular septal thickening and paraseptal emphysema, which is most severe in the peripheral portions of the upper lobes and in the superior segments of the lower lobes. A few irregular cysts and ground glass nodules are also seen, mostly in the right upper lobe.
H&E stains show regions of nodular fibrosis with surrounding cystic change. Other regions show homogeneous interlobular septal fibrosis. CD1a and CD207 (Langerin) stains both show scattered intra-alveolar staining.
Case Discussion
In a patient with chronically progressive dyspnea and pulmonary function tests showing restrictive physiology, suspicion for interstitial lung disease is raised. CT of the chest showing fibrotic and cystic changes corroborates this suspicion. The subpleural and symmetrical distributions are suggestive of non-specific interstitial pneumonia (NSIP), but the upper lobe predominance is not. Although the patient is older than would be expected, upper lobe predominant fibrosis with cyst formation suggests the possibility of pulmonary Langerhans cell histiocytosis (LCH). Multiple wedge biopsies of the right lung were performed to ascertain the diagnosis.
As with the imaging, architectural changes in portions of the right upper and right lower lobes are suggestive of fibrotic NSIP. However, other regions show sclerotic foci surrounded by cystic change. CD1a and CD207, two immunohistochemical stains with high specificity for Langerhans cells, did stain focally in the alveoli, making this histology more consistent with the fibrotic phase of LCH.
Case courtesy of Dr Cristina Fuss and Dr David Sauer for their contributions to this case.