The prevalence and significance of clinically unsuspected neoplasms in cervical lymph nodes

Histopathologic scrutiny of surgical pathology specimens can uncover unexpected but important pathologic processes that might not (yet) be clinically apparent. We suspect that cervical lymph nodes removed from patients with known cancers of the head and neck might occasionally harbor clinically unsuspected neoplasms.

We reviewed the pathology reports of all patients who had undergone cervical lymph node dissections at our institution between 1984 and 2001 to determine the prevalence of occult metastatic thyroid cancer and other clinically unsuspected tumors. The medical records were reviewed to obtain follow-up information when histologic examination disclosed some significant finding that was unsuspected on clinical grounds.

Of the 1337 patients who underwent cervical lymphadenectomy during the 17-year period, 27 (2.0%) had at least one lymph node harboring an unanticipated finding that raised the concern of a clinically unsuspected neoplasm. Sixteen (1.2%) of these patients had conclusive histologic evidence of an unexpected neoplasm, including 6 patients (0.4%) with malignant lymphomas (low-grade B cell, n = 5; high-grade B cell, n = 1) and 10 patients (0.7%) with metastatic papillary thyroid carcinomas. An additional 11 patients (0.8%) had lymph nodes harboring "benign" thyroid inclusions or psammoma bodies. Four of these 11 patients underwent thyroidectomy, but thyroid cancer was not detected in the ipsilateral thyroid. Only one patient died as a consequence of the incidentally discovered neoplasm.

To the degree that our study population is reflective of the adult population at large, at least 1% of adults harbor malignant neoplasms in their cervical lymph nodes. Although this statistic seems alarmingly high, most of these neoplasms are indolent and do not undergo unrelenting progression to clinically overt malignancies.