Multiple primary neoplasia of the head and neck and lung. The changing histopathology.

The authors reviewed 1373 consecutive cases of patients with oral head and neck cancer or lung cancer and identified 25 patients with multiple primary neoplasia (MPN). All 25 MPN cases had squamous carcinoma of the head and neck; however, only 40% (N = 10) had squamous carcinoma of the lung. The histologic types of non-squamous lung carcinoma were: adenocarcinoma 36% (N = 9), small cell carcinoma 20% (N = 5), and large cell undifferentiated carcinoma 4% (N = 1). Of 927 cases of MPN of the head and neck and lung reported in the English language literature, only 100 cases (10.78%) demonstrated a histologic discrepancy between the primary tumors. Recent reports demonstrate a histologic shift toward non-squamous lung carcinoma in MPN that is similar to our data, and that corresponds to the increase in non-squamous carcinomas recently seen in lung cancer in general. Possible implications of these findings are discussed.