Oral Reactive Cutaneous Capillary Endothelial Proliferation Induced By Camrelizumab

Camrelizumab, a new immune checkpoint inhibitor, shows considerable antitumor effects but may lead to immune-related adverse events (irAEs), such as the distinctive occurrence of reactive cutaneous capillary endothelial proliferation (RCCEP). Here we present a case of gingival RCCEP triggered by Camrelizumab in a patient with metastatic small intestine adenocarcinoma. A 59-year-old woman presented with gingival bleeding, swelling, and a painless mass on the right maxillary gingiva after two months of Camrelizumab and chemotherapy. She had previously undergone surgical resection for small intestine adenocarcinoma and later developed multiple metastases. Upon oral examination, a red, soft, nodular mass was observed on the gingiva between teeth 11 and 12, accompanied by gingival hyperemia and hypertrophy. Following scaling and the withdrawal of Camrelizumab, the gingival swelling improved, but the mass remained unchanged. Consequently, the lesion was excised at the margin, and histopathology revealed fibrovascular proliferation with inflammatory cell infiltration, consistent with RCCEP. The patient has shown no recurrence during follow-up to date. Despite the high incidence of RCCEP, oral lesions were rarely reported. RCCEP is a distinctive irAE associated with Camrelizumab, possibly due to its effect on vascular endothelial cells. Although RCCEP is generally self-limiting, intervention may be necessary for lesions causing functional impairment or bleeding risk. In our case, the patient developed oral RCCEP two months after Camrelizumab and was cured with conservative treatment and surgery. In conclusion, gingival RCCEP may develop during Camrelizumab treatment, highlighting the necessity for pre-treatment oral care and to reduce such complications.