Presentation
History includes smoking 1.5 packs per day, COPD, and papillary thyroid carcinoma. Imaging was performed for surveillance of her thyroid cancer. She reported progressive dyspnea over several months at the time of imaging. Pulmonary function tests performed at the time demonstrated a mixed restrictive/obstructive pattern.
Patient Data
There several ground glass nodules and mild centrilobular emphysema in both upper lobes. There is no evident fibrosis.
H&E stains show large groups of macrophages centered in the small airways, stellate nodules, and cystic change. CD1a immunohistochemistry, which is specific for Langerhans cells, is diffusely positive.
12.5x H&E stain
Sclerotic foci (blue arrow) are surrounded by emphysema (red arrow).
400x HE
Clusters of macrophages are centered in the small airways.
100x CD1a immunohistochemistry
Diffusely positive for Langerhans cells.
Case Discussion
In a patient with a history of papillary thyroid carcinoma, new pulmonary nodules are suspicious for metastatic disease. However, ground glass is uncharacteristic of metastatic PTC, and wedge biopsies were performed to establish the diagnosis.
Pathology shows large groups of macrophages centered in the small airways, fibrotic change forming stellate nodules, and early cyst formation. Confirmation was achieved with CD1a immunohistochemistry, a stain specific for Langerhans cells. CD1a immunohistochemistry was diffusely positive. Cultures were negative.
The rapid evaluation prompted by suspicion for metastatic thyroid cancer has yielded interesting radiologic and pathologic images of the early stage of Langerhans cell histiocytosis.
Thanks to Dr Cristina Fuss and Dr David Sauer for their contributions to this case.
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