LANGERHANS CELL HISTIOCYTOSIS OF THE THYROID - A SERIES OF 7 CASES AND A REVIEW OF THE LITERATURE

Langerhans cell histiocytosis is a rare disorder, with a few reports d escribing isolated thyroid gland involvement. We report seven cases, w hich included four females and three males ranging in age from 2 month s to 55 years, with a median age of 37 years. Histologically, the case s demonstrated either diffuse or focal involvement of the thyroid glan d by Langerhans cell histiocytes, characterized by bean-shaped, lobate d, folded nuclei. In association with the histiocytic infiltrate, ther e was a prominent eosinophilic cellular component, as well as destruct ion of the thyroid follicles. All cases occurred in a background of ly mphocytic thyroiditis. One case demonstrated adenomatoid nodules, wher eas another had a microscopic papillary carcinoma. Immunohistochemical staining demonstrated positive reactivity with S-100 protein, lysozym e, and KP-1. Four patients with isolated thyroid disease, treated by s urgical resection alone, are alive without systemic disease from 3 to 19 years after initial presentation. The three patients with systemic disease died within 1 year of the initial diagnosis with disease-relat ed complications. Localized disease portends a favorable prognosis as compared to the thyroid involvement as part of systemic disease.