Thyroid Langerhans cell histiocytosis concurrent with papillary thyroid carcinoma: A case report and literature review

Langerhans cell histiocytosis of the thyroid mimicking thyroiditis in a boy: a case report and literature review

BACKGROUND

Langerhans cell histiocytosis affecting the thyroid commonly presents with nonspecific clinical and radiological manifestations. Thyroid Langerhans cell histiocytosis is typically characterized by non-enhancing hypodense lesions with an enlarged thyroid on computed tomography medical images. Thyroid involvement in LCH is uncommon and typically encountered in adults, as is salivary gland involvement. Therefore, we present a unique pediatric case featuring simultaneous salivary and thyroid involvement in LCH.

CASE PRESENTATION

A 3-year-old boy with complaints of an anterior neck mass persisting for 1 to 2 months, accompanied by mild pain, dysphagia, and hoarseness. A physical examination revealed a 2.5 cm firm and tender mass in the left anterior neck. Laboratory examinations revealed normal thyroid function test levels. Ultrasonography revealed multiple heterogeneous hypoechoic nodules with unclear and irregular margins in both lobes of the thyroid. Contrast-enhanced neck computed tomography revealed an enlarged thyroid gland and bilateral submandibular glands with non-enhancing hypointense nodular lesions, and multiple confluent thin-walled small (< 1.5 cm) cysts scattered bilaterally in the lungs. Subsequently, a left thyroid excisional biopsy was performed, leading to a histopathological diagnosis of LCH. Immunohistochemical analysis of the specimen demonstrated diffuse positivity for S-100, CD1a, and Langerin and focal positivity for CD68. The patient received standard therapy with vinblastine and steroid, and showed disease regression during regular follow-up of neck ultrasonography.

CONCLUSIONS

Involvement of the thyroid and submandibular gland as initial diagnosis of Langerhans cell histiocytosis is extremely rare. It is important to investigate the involvement of affected systems. A comprehensive survey and biopsy are required to establish a definitive diagnosis.

Early chemotherapeutic intervention to avoid thyroidectomy in pediatric Langerhans cell histiocytosis with thyroid involvement accompanying tracheal stenosis: a report of two cases

Thyroid involvement is rare in pediatric Langerhans cell histiocytosis (LCH). It may cause airway narrowing, leading to acute-onset respiratory distress. Severe cases may require emergent surgical interventions such as thyroidectomy, which should be avoided in children due to higher rates of complication, particularly in infancy. There is currently no consensus on the indications for surgical treatment in LCH with thyroid involvement. In this report, we describe the cases of two children who presented with tracheal stenosis caused by thyroid LCH, both of which were successfully treated by early induction of chemotherapy, and one of which was also treated for a shorter duration. Mutation analysis detected in-frame deletions of BRAF exon 12 in both cases. These cases suggest that timely diagnosis and administration of chemotherapy may alleviate severe airway obstruction and reduce the need for thyroidectomy in pediatric patients with thyroid LCH.