A Unique Presentation of Concurrent Duodenal and Peritoneal Metastasis From Head and Neck Cancer.

Metastatic disease to the duodenum or peritoneum from a primary head and neck carcinoma is an extremely rare presentation. We report the case of a 68-year-old male with a history of head and neck squamous cell carcinoma (HNSCC) who presented with worsening nausea, abdominal pain, postprandial vomiting, and early satiety for over two months. Prior to this presentation, he was evaluated for several postauricular lumps, with computerized tomography (CT) scan showing a supraglottic mass and an excisional biopsy of a postauricular nodule confirming metastatic HNSCC. A CT scan of the chest, abdomen, and pelvis during the admission showed worsening lymphadenopathy in the mediastinum and hilar regions, as well as new ascites and peritoneal lesions. Esophagogastroduodenoscopy showed a large erythematous nodular lesion in the second portion of the duodenum occupying approximately one-third of the lumen circumference. Similar to the previously worked up nodule, histology from the duodenal mass biopsies showed metastatic poorly differentiated squamous cell carcinoma that was strongly positive for p63 and p16. Thus, we report the first case of concurrent duodenal and peritoneal metastasis from an HNSCC.