Radiation recall reactions triggered by COVID-19 infection in a patient with buccal cancer; A clinical report and review of the literature.

A case of a patient who developed a radiation recall reaction (RRR) triggered by coronavirus disease 2019 (COVID-19) infection following surgery and chemoradiotherapy for carcinoma of the buccal mucosa is reported. A 75-year-old woman presented in October 2023 with pyrexia and erythema extending from the left cheek to the anterior chest area. In December 2021, she had undergone surgery to remove a carcinoma of the left buccal mucosa (pT2N0M0), followed by left comprehensive neck dissection for delayed cervical lymph node metastasis in June 2022, with subsequent adjuvant chemoradiotherapy. Her course was uneventful until September 2023, when she developed COVID-19. Twenty-three days after COVID-19 infection had been confirmed, she developed systemic pyrexia with erythema and a heat sensation from her left cheek to the left anterior chest. On presentation, her temperature was 39 ºC, and she had a mild sore throat. Erythema and a heat sensation were apparent from the left cheek to the neck and anterior chest, corresponding to the previously irradiated area. Laboratory tests showed a white blood cell count of 11,760/μl, and C-reactive protein of 16.0 mg/dl. Computed tomography did not show any obvious abscess formation or infection source. An RRR was diagnosed, and she was admitted for treatment with intravenous sulbactam/ampicillin and intravenous hydrocortisone sodium succinate. Five days after admission, the inflammatory reaction had improved, and she was discharged. Her subsequent course has been uneventful, with no flareup of the RRR. This case is presented along with a review of relevant literature.