Quintuple Primary Cancers Including Intraductal Papillary Mucinous Carcinoma: A Case Report.

[INTRODUCTION] The incidence of multiple primary malignancies has increased owing to advances in cancer screening and treatment. However, cases involving five distinct primary cancers remain extremely rare. Intraductal papillary mucinous neoplasms (IPMNs) are known to be associated with extrapancreatic malignancies. We report a very uncommon case of quintuple primary cancers, including noninvasive intraductal papillary mucinous carcinoma (IPMC), and discuss its clinical implications.

[CASE PRESENTATION] A 77-year-old man was referred for evaluation of pancreatic duct dilatation incidentally detected during staging for hypopharyngeal cancer. He had been diagnosed with hypopharyngeal squamous cell carcinoma and underwent radiotherapy. During this evaluation, a colonoscopy revealed sigmoid colon cancer, which was treated with a laparoscopic sigmoidectomy (pT2N0M0). Imaging revealed main pancreatic duct dilatation with a 15-mm enhancing mural nodule in the pancreatic head, meeting the criteria for high-risk stigmata of IPMN and prompting further pancreatic evaluation. Endoscopic ultrasonography demonstrated a 19 × 4 mm intraductal papillary lesion in the pancreatic head duct, consistent with an IPMN with high-risk stigmata. A pancreaticoduodenectomy was performed, and the pathology report confirmed noninvasive IPMC with negative margins and nodes (pTisN0M0). One year later, routine surveillance detected a solitary right middle-lobe lung nodule; thoracoscopic lobectomy confirmed squamous cell carcinoma (pT1aN0M0). At age 81, the patient was diagnosed with prostate cancer and began hormonal therapy. Histopathological diagnoses revealed five distinct malignancies without evidence of metastasis. The patient is currently alive and under surveillance without evidence of recurrence.

[CONCLUSIONS] Quintuple primary cancers including noninvasive IPMC are very uncommon. Patients with IPMN/IPMC may require risk-adapted and long-term follow-up for synchronous or metachronous malignancies.