Deep Cutaneous Candidiasis With Costal Osteomyelitis Following Pectoralis Major Myocutaneous Flap Reconstruction: A Case Report.

Candida is a yeast commonly found in various environments. It usually coexists with the skin without causing harm. It may exhibit pathogenicity when local or systemic immune defense mechanisms are compromised, which creates conditions favorable for its proliferation. This report discusses a case of invasive cutaneous candidiasis with rib osteomyelitis that developed at the donor site of a pectoralis major myocutaneous flap. The patient was a 58-year-old man who underwent reconstruction with a pectoralis major myocutaneous flap for adenoid cystic carcinoma in the midline floor of the mouth. Six months postoperatively, a reddish mass appeared at the donor site in the anterior chest. C. albicans was isolated from this lesion. Despite undergoing curettage and receiving oral antifungal treatment, the lesion showed no improvement. The reason for the treatment failure remains unclear. Consequently, surgical resection, including the fourth rib, was performed. Based on clinical, histopathological, and microbiological evaluations, the patient was diagnosed with deep-seated cutaneous candidiasis with rib osteomyelitis. The patient has been followed for 19 years postoperatively, with no evidence of recurrence of the primary floor-of-mouth carcinoma or candidiasis.