Multifocal Langerhans cell histiocytosis involving the thyroid and several organs: a diagnostic dilemma

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder of antigen-presenting cells (dendritic cells) with variable clinical presentation. Involvement of the thyroid gland, parotid gland, lungs, and salivary glands is exceedingly rare and often mimics malignancy, such as lymphoma or metastatic disease. It can closely mimic other thyroid malignancies. Immunohistochemistry remains crucial for diagnosis. Early recognition prevents unnecessary radical surgery and allows tailored multidisciplinary management. We report a 42-year-old woman with long-standing hypothyroidism presenting with bilateral thyroid swelling and submandibular and parotid enlargement. Imaging suggested chronic thyroiditis. High-resolution computed tomography of the chest revealed bronchiectasis. Total thyroidectomy was performed for diagnostic clarification. Immunohistochemistry revealed a diffuse population of CD1a- and CD68-positive cells, confirming LCH. This represents a rare case of multifocal head and neck LCH involving both thyroid lobes, the submandibular and parotid glands, and the lungs.