First report of squamous cell carcinoma arising within an intraoral radial forearm free flap

Oral epithelial dysplasia within free tissue reconstructions of the oral cavity has been reported. We report a case where squamous carcinoma arose within radial forearm skin transferred to the oral cavity 23 years previously. After a thorough literature search we believe this is the first report of such a phenomenon.

A 62-year-old man presented to our service with pain and a new mass in the left floor of mouth. The floor of mouth had been reconstructed with a radial forearm free flap (RFFF) 23 years earlier following resection of a mucosal squamous cancer. This new mass was within the reconstruction tissue. Biopsy showed multiple areas of dysplasia and a single new focus of invasive carcinoma. This new tumour was excised and reconstructed with a contralateral nasolabial flap. Formal histology showed an arrector pili muscle adjacent to invasive cancer. Some years earlier dysplasia had been noted in the free flap skin component.

The skin component of free tissue transfer reconstruction flaps has been shown to develop epithelial dysplastic change. This has been found to be associated with similar levels of p53 mutation and increased Ki-67 expression within this intraoral skin and adjacent dysplastic mucosa. Our case demonstrates similar levels of expression of mutated p53 and Ki-67 in in situ epithelium and in invasive tissue perhaps supporting the idea of expansion of premalignant cells into the skin flap epidermis.

We have shown for the first time that a new SCCa has developed within the cutaneous component of a free tissue transfer flap. With improved longevity of patients treated with primary surgery for oral cavity SCCa there is need for vigilance in monitoring for this cancer recurrence site.