Intrathyroidal neurofibroma, a case report.

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disease. It is characterized by café-au-lait spots, melanocytic hamartomas of the iris, pseudo-freckles, neurofibromas, and tumor predisposition. The presence of neurofibromas in the thyroid gland is extremely rare. Here we present the case of a 6-year-old male patient with NF1 who consulted at the Department of Endocrinology due to a thyroid tumor and whose ultrasound confirmed a heterogeneous mass at the posterior level of the right lobe. A cervical surgery found the tumor was adhered to the larynx and trachea, with the recurrent laryngeal nerve entering the tumor. Due to the impossibility of dissection, a right hemithyroidectomy was performed and the pathological examination confirmed the presence of plexiform neurofibroma and intrathyroidal neurofibroma. This is the second case reported in childhood and the youngest case to date. Neurofibroma with thyroid involvement should be suspected in patients with cervical mass and NF1, since diagnostic guidance allows avoiding unnecessary studies and guide treatment.