Metastatic squamous cell carcinoma (SCC) from an unknown primary site to the colon
has not been reported previously. A 75-year-old woman presented with a mass in the
left submandibular region. Biopsy revealed a Class V lesion, but the histologic type
was undetermined. Surgical resection of the left submandibular gland with cervical
lymph node dissection was performed. However, SCC was seen in the lymph nodes only,
with no tumor in the submandibular gland. Three months after surgery, computed
tomography revealed that the preoperatively diagnosed lesion in the transverse colon
had grown considerably. A laparoscopic right hemicolectomy was performed.
Histological examination showed features of SCC, similar to the findings in the
cervical lymph nodes. We report a rare case of synchronous metastatic SCC to the
colon and cervical lymph nodes from a carcinoma of unknown primary site.