Incidental metastases of well-differentiated thyroid carcinoma in lymph nodes of patients with squamous cell head and neck cancer: eight cases with a review of the literature.

The examination of a large series of cervical lymph nodes in patients with head and neck cancer revealed the presence of incidental metastases of occult thyroid carcinoma in eight patients, of which six cases were squamous cell carcinoma of glottic and supraglottic sites of the larynx and two cases were pyriform sinus and tongue carcinomas. Three patients had two lymph nodes and the remaining patients had one lymph node each involved. The nodal chains affected were the jugular (n=5; level IV), Kuttner (level II), supraomohyoid (level III) and supraclavicular (level VI). In four cases, a subtotal thyroidectomy or unilateral lobectomy was performed during laryngectomy (for surgical reasons) or after histologic nodal examination; a minimal focus of thyroid papillary carcinoma was detected in one patient. Three of eight patients died from recurrence of the squamous cell carcinoma; no case presented clinical evidence of thyroid malignancy. The differential diagnosis from benign thyroid heterotopia was based on the presence of minimal nuclear atypia. The choice of treatment of patients with a coexisting neoplasm characterized by poor prognosis is difficult, and contrasting opinions exist regarding the use of radical thyroidectomy and the subsequent management. As reported in the literature (66 cases), the more aggressive squamous cell carcinoma will determine the prognosis of these patients; in fact, only one of the referred cases died of cerebellar metastases of the thyroid cancer. Our results emphasize the importance of an accurate re-evaluation and follow-up of patients with incidental occult metastases for detection of a primary thyroid tumor. In the general population, this incidental nodal involvement may be related to a minimal occult thyroid carcinoma.