A challenging diagnosis: Case report of oral metastasis from gastric adenocarcinoma mimicking pyogenic granuloma.

ABSTRACT

RATIONALE Oral metastases occur more commonly in bone, but can also manifest in soft tissues and eventually resemble a reactive lesion. Few cases of oral metastases mimicking reactive lesions in soft tissues have been reported to date. PATIENT CONCERNS We report a metastasis of gastric carcinoma (GC) to the oral mucosa without bone involvement in a 43 yom clinically and microscopically mimicking a reactive lesion. The patient related that the lesion had 1 month of evolution, and the ulcerated area suggested the lesion was related to trauma. DIAGNOSES The histopathological examination of the lesion revealed an exuberant granulation tissue with few neoplastic cells, and the initial diagnosis of pyogenic granuloma was considered. In a second analysis, clusters of clear cells morphologically similar to degenerating mucous cells or macrophages, positive for Cytokeratin (CK)-20, and CDX2 were found. At the moment, it was confirmed the presence of a primary GC in the patient. INTERVENTIONS: A palliative radiotherapy/chemotherapy was started. OUTCOMES: However, the patient died 3 months after the diagnosis of oral metastasis. LESSONS This report highlights the importance of careful clinical and microscopic examinations in cases of oral metastasis that may mimic a reactive lesion.