Langerhans cell histiocytosis of the frontal bone with unexpected manifestations: Rare case report

INTRODUCTION: Langerhans cell histiocytosis (LCH) is a disease caused by clonal expansion of myeloid precursors that differentiate into specialized dendritic cells. PRESENTATION OF CASE: A 21-year-old female came to our hospital complaining of tachycardia, high temperature, and tumor formation in the frontal region with a fistula. The examination of the thyroid gland and other systems was normal. The radiological investigations showed a severe lytic osseous lesion with aggressive destruction of the bone. The ultrasound imaging of the thyroid gland revealed that the thyroid was generally hypoechoic and heterogeneous because of many small hypoechoic focuses. In addition, the blood perfusion increased in the gland. The laboratory investigations were within normal expect C-reactive protein, free T4, and TSH. The surgery was indicated. The patient underwent an excision of the mass by a specialist in neurosurgery. The histopathological examination of the excised mass revealed LCH (eosinophilic granuloma). After 6 months, the patient underwent cranioplasty. The follow-up was uneventful for 3 months until the patient suffered from hyperthyroidism. DISCUSSION: LCH can form in any part of the body, and cause many symptoms depending on its location. Even though hyperthyroidism is a rare and unexpected symptom of LCH. CONCLUSION: LCH is a disease with broad-spectrum manifestations, so it should be a differential diagnosis in bone, thyroid, skin, and other organ lesions. In addition, thyroid ultrasonography and laboratory investigations are important methods to estimate thyroid functions and determine the clinical classification of the disease.