Head and Neck Metastasis of Colorectal Adenocarcinoma: A Case Report and Literature Review

Background: Colorectal Adenocarcinoma (CRC) metastasis is found in approximately 1 in 5 patients diagnosed with CRC and frequently spreads to the liver, lungs, peritoneum, bone, and nervous system. There are several subtypes of adenocarcinoma but the single most associated with distant metastasis, multiple sites of metastasis, and poorer survival is the signet-ring cell carcinoma variant. We present an unusual case of a head and neck mass demonstrating immunohistochemical staining specific for colorectal origin in a patient with a history of mucinous adenocarcinoma of the colon. Case Presentation: A 53-year-old female was referred for a left cervical neck mass associated with newly developed left eye ptosis and dryness. Physical examination confirmed the presence of a palpable, non-fluctuant, left level IV neck mass with no cervical lymphadenopathy. Further evaluation of social and medical history concluded that patient was a non-smoker and never consumed alcohol but did have previous mucinous adenocarcinoma that was treated with a hemicolectomy and was currently in remission. Immunohistochemical stains of ultrasound fine needle aspiration biopsy revealed malignant cells to be partially reactive to CK20 and CDX2, while negative for CK7 – a relatively specific staining pattern for intestinal origin. Conclusions: In conclusion, this case report highlights the importance of considering primary infraclavicular cancers as part of a complete differential diagnosis when evaluating head and neck metastasis. Acknowledging this potential may provide enhanced insight in delivering patient-centered, evidence-based treatment options and disease management that can ultimately improving patient outcome.