Immunoperoxidase stain for CD1a (OKT6): The antibody reacts with the cell membrane. Note the two giant cells. Giant cells are infrequent but account for the terms, eosinophilic granuloma and Langerhans' cell granulomatosis, formerly used for this disease.

A

This section (B), which is also stained for CD1a, shows the edge of a cavitated nodule with positively staining Langerhans' cells in alveolar walls and spaces. Lysis of alveolar walls (arrow) often occurs around lesions and produces the pericicatricial* emphysema typical of the late, scarred lesion [1].

*A cicatrix is a scar.

B

Reference

1. Hayashi T, Rush W, Travis W, Liotta L, Stetler-Stevenson W, Ferrans V. Immunohistochemical study of matrix metalloproteinases and their tissue inhibitors in pulmonary Langerhans' cell granulomatosis. Arch Pathol Lab Med 1997; 121:930-937.

Clinical summaryImage 3

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