Primary mucinous adenocarcinoma of the lung with signet-ring cells: A histochemical comparison with signet-ring cell carcinomas of other sites

Five cases of primary mucinous adenocarcinomas of the lung with signet-ring cells were studied with regard to clinical, pathologic, and prognostic implications and compared with the signet-ring cell adenocarcinomas of extrapulmonary sites. The patients ranged in age from 55 to 74 years, with a mean age of 67.8 years. There were three men and two women. Histologically, three cases were usual adenocarcinomas and two were bronchioloalveolar carcinomas. The percentage of signet-ring cells ranged from 10% to 50%, with a mean of 22% and a median of 20%. Therapy included lobectomy, radiation, and chemotherapy. Three of five patients died of their disease within 9 months and two patients showed no evidence of disease 5 months after presentation. Routine histology showed no significant differences between the signet-ring cells of any of the tumors; however, by special histochemistry, tumors originating from lung, stomach, and colon showed a more intense reaction with alcian blue stain than tumors from nose, breast, or bladder. Contrary to a previous report, we found no increase in sulfated acid mucins in these five cases of lung tumor. We also were unable to demonstrate a qualitative or quantitative difference between mucopolysaccharides produced by lung, stomach, or colon tumors. Although rare, mucinous adenocarcinoma of the lung with signet-ring cells can exist as a primary tumor.