Isolated Langerhans Cell Histiocytosis of Thyroid-Masquerading as a Thyroid Neoplasm - A Rare Case Report

Abstract

Langerhans Cell Histiocytosis (LCH) is a rare neoplastic disease of unknown etiology characterized by oligoclonal proliferation of langerhans cells with a varying incidence rate of 4-5.4 per 1 million individuals. LCH occurs in localised and multifocal forms. LCH lesions were first described in the year 1893, they are composed of large histiocytes with abundant cytoplasm intermixed with lymphocytes and eosinophils. Diabetes insipidus is the most common endocrinological abnormality of LCH. Other manifestations such as hypothalamic/pituitary axis disturbance and anterior pituitary deficiency can occur resulting in secondary or tertiary hypothyroidism. Cases of LCH with isolated thyroid involvement are very rare. We present a case of LCH, in a 42-year-old female who had a nodular thyroid swelling since one and a half year with euthyroid status. Total thyroidectomy specimen was received with a clinical diagnosis of thyroid neoplasm. Histopathology revealed langerhans histiocytes both mononucleated and multinucleated with prominent nuclear grooves, accompanied by good number of eosinophils and lymphocytes. Histopathology diagnosis of LCH was given supported by IHC S-100 and CD 1a positivity. Since, it’s a rare entity it needs to be distinguished from its closer mimics non Hodgkin’s lymphoma and Rosai Dorfman’s disease. Treatment of choice is surgical resection, but there is no evidence of improved outcome on usage of adjuvant chemoradiotherapy for primary thyroid LCH post resection. So, more case reports and articles are recommended to acess treatment regimen for better outcome.