Solitary pulmonary metastasis from a gingival cancer of 36 years ago: A case report

INTRODUCTION: Unlike a squamous cell carcinoma (SqCC), an adenoid cystic carcinoma (ACC) is an uncommon histology of all head and neck cancers. The clinical significance of a pulmonary metastasectomy differs greatly between these two types of cancers. A solitary pulmonary nodule in a patient with a history of both these different malignancies is a diagnostic and therapeutic challenge. PRESENTATION OF CASE: An 81-year-old woman presented with a right lung nodule detected by chest computed tomography (CT) one year after a tongue SqCC surgery. She had a remote history of gingival cancer 36 years prior, which was not assessed in detail during the initial work up. We suspected that the nodule was a primary lung cancer and she underwent a right basal segmentectomy. Histology revealed an ACC, which was proven to be a metastasis from the gingival cancer. DISCUSSION: An ACC is an uncommon type of cancer arises mainly in the salivary glands. It is characterized by a long-term behavior and the histology of ACC is a favorable prognostic factor. With its favorable histology and disease free interval of over 30 years, a better outcome would be expected than that of a primary lung tumor or a metastasis from the tongue SqCC. Furthermore, we could have made a differential diagnosis of a metastatic ACC before the surgery with more careful research for a previous history of a gingival cancer. CONCLUSION: Our case emphasized that a precise history taking of any malignancy, even if that of more than 30 years prior, is crucial.