The differential diagnosis of the mass in the neck. A fresh look.

A diagnosis of undifferentiated carcinoma by light microscopy in a neck node biopsy is insufficient to come to a conclusive answer as to the type of tumor with which one is dealing. The fact that undifferentiated carcinoma by light microscopy may very well be a histiocytic lymphoma with a different mode of treatment and an increasingly improved cure rate has changed the mode of evaluation in arriving at a diagnosis of the node in the neck with no visible primary in the upper aerodigestive tract.