Metastasis of cutaneous squamous cell carcinoma to the duodenum: a case report

The gastrointestinal (GI) tract is an uncommon site for metastasis in cutaneous squamous cell carcinoma (cSCC). When it is involved, it typically manifests with GI bleeding, anemia, malabsorption, and abdominal pain. Endoscopic evaluation and histopathological confirmation are essential for definitive diagnosis. Currently, there is limited literature on this phenomenon, with all reported cases indicating a poor prognosis.

We present a case of duodenal metastasis from an untreated cSCC patient with a 3-year history. This woman initially presented with abdominal pain and GI bleeding. Despite prompt diagnostic workup and active treatment, the outcome was unfavorable. Noncontrast CT and contrast-enhanced CT strongly suggested a malignant duodenal mass. To obtain a definitive diagnosis, oral small bowel endoscopy was performed, which directly visualized a carcinoma within the duodenum. Histopathological examination of the endoscopic biopsy specimen confirmed the presence of invasive carcinoma. Immunohistochemical analysis and exclusion of other primary sites by clinical and radiological examinations suggested that the duodenal tumor was likely a metastasis from cutaneous squamous cell carcinoma involving retroperitoneal lymph nodes. The patient ultimately died from massive gastrointestinal hemorrhage.

The gastrointestinal tract is a rare site of metastasis for cutaneous squamous cell carcinoma, often presenting with nonspecific clinical symptoms. This case highlights the critical importance of early and aggressive management of the primary tumor.