A case report of invasive candidiasis and fungal osteomyelitis mimicking oropharyngeal carcinoma recurrence in an immunocompetent patient following transoral robotic surgery

•TORS for oropharyngeal tumour may predispose susceptible patients to invasive fungal infection and osteomyelitis.•Susceptible patients included those with prior history of radiation at surgical site.•Fungal infection can present as an exophytic mass at the surgical site.

IntroductionTransoral robotic surgery(TORS) for the excision of oropharyngeal tumour is increasingly considered for its lower rates of postoperative complications and better functional outcomes. However, we report a case of invasive candidiasis in an immunocompetent patient with previous radiation therapy years ago who underwent TORS recently.Case presentationA 55 year old Chinese female with previous radiation therapy for nasopharyngeal carcinoma diagnosed in 1986 underwent wide excision of a newly diagnosed oropharyngeal carcinoma with TORS. From 4 to 8 weeks post-op, an enlarging exophytic lesion at the surgical excision site was noted. Initial biopsy did not show malignancy or fungal organisms. A repeat biopsy under anaesthesia was done as CT imaging showed suspicion of either infective or tumour recurrence. The patient was treated with long term antifungals as final culture results showed invasive candidiasis. The surgical site showed no further lesions 6 months post-op.DiscussionPrevious radiation therapy to the oropharyngeal area predisposes a patient to colonization of fungal organisms. Despite TORS showing lower rates of infection, patients who have had previous radiotherapy may be more susceptible to infections as the dissection involves down to the pre-vertebral fascia. Hence, it is appropriate for such patients to have microbiological and fungal cultures performed for a lesion such as this and be treated according to the results of the culture.ConclusionThis case serves as a reminder of the risk of invasive candidiasis requiring early investigation and treatment in an immunocompetent patient with prior history of both radiation therapy and recent TORS.