Repeated occurrence of second primary lung cancer at different sites in trachea: a case report

Multiple or second primary lung cancers can develop at any sites in the lung with same or different histologic types, synchronously and/or metachronously. In case of metachronous occurrence of the second primary lung cancer, it is easy to confuse with the primary lung cancer as a recurrence of precedent lung malignancy treated successfully or metastasis. Previous reports have demonstrated that majority of the second primary lung malignancies have same histologic types regardless of their developing time and location. However, the repeated occurrence of the second primary lung malignancy, in particular with the different histologic features, is a very rare condition.A 62-year-old male who had past history of squamous cell carcinoma treated with surgery and adjuvant chemotherapy and the recurrence of lung malignancy on the trachea, which was also resected successfully visited our hospital due to blood tinged sputum. Evaluation using bronchoscopy and chest computed tomography revealed the tracheal mass looked similar grossly to the previous recurred tracheal mass that was resected surgically. Unexpectedly, the newly developed tracheal mass was confirmed as small cell lung cancer, the different histologic type from previous ones.In this report, we describe an interesting case of subsequent occurrence of second primary lung cancers showing histologic shifting at different sites in trachea, suggesting that it is important for physician to make an effort to identify the histologic characteristics of second primary lung cancers for the correct and adequate treatment no matter what they exhibit similar gross morphology.