Primary signet-ring squamous cell carcinoma of the oral cavity: The first intraoral case

Abstract

Introduction: The aim of this paper was to report a case of primary signet-ring squamous cell carcinoma in the floor of the mouth and highlight the importance of complete oral examination. Case report: We report the case of a 54-year-old man who complained of pain and difficulty to open the mouth. The patient presented to the outpatient clinic after he had visited 18 dentists without any definite diagnosis. Oral examination showed a mass in the submandibular gland and an ultrasound revealed an expansive lesion. Histopathological analysis showed the presence of a tumour infiltrating adjacent tissue with groups of cells exhibiting a signet-ring appearance. PAS and mucicarmine was negative. Immunohistochemical staining for CK7 and EMA was strongly positive and Ki67 staining was weakly positive. The lesion was completely submucosal and no ulceration was observed. Conclusion: This case of signet-ring cell SCC originating from the excretory duct of the submandibular gland represents a rare variant of oral SCC and highlights the importance of complete oral examination, including palpation.