Primary embryonal rhabdomyosarcoma of the anterior neck and thyroid: report of a new case with review of the literature.

Primary embryonal rhabdomyosarcoma of anterior neck involving the thyroid is extremely rare. This report is only the second of its kind that describes this form of nonorbital nonparameningeal rhabdomyosarcoma in a 7-year-old boy and adds to a new, seldom-reported variant of rhabdomyosarcoma in the head-neck region. The child presented with a huge anterior neck swelling that clinically resembled a thyroid mass. Computed tomography scan showed a heterogeneous mass in the anterior neck replacing the entire right lobe of thyroid. Fine-needle aspiration cytology was nondiagnostic. Right hemithyroidectomy with selective neck dissection suggested embryonal rhabdomyosarcoma by histopathology; the diagnosis was confirmed by positive reactions to desmin and myogenin. The child was subsequently treated with chemotherapy. Repeat chemotherapy with radiotherapy was required when recurrences were detected in the mediastinum and cervical lymph nodes at 13-month follow-up.