Metastatic signet ring cell carcinoma to oral cavity: A case report

• Published in: Oral surgery, oral medicine, oral pathology and oral radiology oral medicine, oral pathology and oral radiology, 2025-01, Vol.139 (1), p.e20-e20
• Main Authors: Alshuaibi, H, Bhattacharia, I, Islam, MN
• Format: Article
• Language: English
• ISSN: 2212-4403
• DOI: 10.1016/j.oooo.2024.10.209

Signet ring cell carcinoma (SRCC) is an aggressive adenocarcinoma variant often originating from the gastrointestinal tract and known for its poor prognosis. Metastatic lesions of gastric origin to the oral cavity was rare, particularly when involving the oral soft tissues. A case of metastatic SRCC which presented as a diffuse gingival enlargement was described. A 74-year-old female patient exhibited a rubbery, tender, erythematous, diffuse swelling of the attached gingiva extending from tooth #19 to #26. Medical history was noncontributory and primary gastrointestinal malignancy was not identified at the initial presentation. Pyogenic granuloma and squamous cell carcinoma were considered in the clinical differential diagnosis. Histopathological examination showed islands of malignant epithelial cells displaying a proliferation of signet ring cells with intracellular mucin displacing the nucleus aside. Pools of extracellular mucin infiltrating the stroma were seen with aggregates of islands of signet ring cells floating in the mucin. Immunohistochemical (IHC) staining was performed, and the neoplastic cells were floridly reactive to CDX2 while negative for ER, PR, and CK7 confirming a colorectal origin. In this rare presentation of SRCC in the oral cavity, the absence of a detectable primary tumor necessitated reliance on histopathological characteristics and IHC markers for diagnosis. The distinctive cellular morphology, combined with CDX2 positivity, was decisive in confirming the metastasis from a colorectal primary. This case serves as a reminder of the importance of considering metastatic tumors in differential diagnoses for oral lesions and demonstrates the utility of immunoprofiling in such atypical presentations.