Clinicopathological characteristics of carcinoma from unknown primary in cervical lymph nodes.

Carcinoma in cervical lymph nodes of unknown origin represents a rare clinical entity where optimal diagnostic and therapeutic management is still a widely debated issue. Molecular classification of these metastases is thus of utmost importance. We analyzed the expression of eight basic molecular markers in 26 metastases from unknown primaries, 31 metastases from overt primaries and their associated primaries. Medical records of the respective patients were reviewed for main clinicopathological parameters. The expression rates showed no significant differences between the two tumor entities, neither in absolute terms nor in comparison among the parameters. Surprisingly, patients with metastases from unknown primary demonstrated improved progression-free survival (p = 0.046) despite advanced age (p = 0.029), advanced nodal stage (p = 0.006) and higher incidence of extracapsular spread (p = 0.045) compared to patients with metastases from overt primaries. Presence of extracapsular spread was associated with increased expression of epidermal growth factor receptor in metastases from overt primaries (p = 0.035) and reduced expression of matrix metalloproteinase-2 in metastases from unknown primary (p = 0.031). We thus conclude that cervical metastases from unknown and overt primaries show similarities in their molecular profile, but fundamental differences in clinical parameter.