Involvement of the thyroid gland in histiocytosis X

A 27 month old white male infant clinically suspected of having histiocytosis X had an enlarged hard hypofunctioning thyroid. A needle biopsy of the thyroid showed disruption of the thyroid architecture by an infiltrate consisting of large histiocytes admixed with eosinophils, neutrophils, and lymphocytes, confirming the clinical diagnosis of histiocytosis X.