Primary signet-ring cell carcinoma of the lung with histochemical characterization

Signet-ring cell carcinoma (SRCC) is a unique sub-type of mucin-producing adenocarcinoma characterized by abundant intracellular mucin accumulation. Although SRCC has been found in various organs, to the best of our knowledge there have only been a few reports of primary SRCC of the lung. Furthermore, most of the reports describe the coexistence of SRCC with differentiated components, while only one case has been reported as pure SRCC. We report here on a patient with primary SRCC of the lung with histochemical characterization. In our case, the tumor cells were mostly composed of signet-ring cells. Although the patient achieved only a minor response after systemic chemotherapy, he has been doing well, without any further treatment, for 33 months after diagnosis.