A patient with squamous cell carcinoma in-situ successfully treated with intralesional 5-Fluorouracil and topical trichloroacetic acid.

Background: The current gold standard and the first line of treatment for non-melanoma skin cancer is surgical excision. Nevertheless, some patients are not good candidates for surgery when wound healing may be impaired.Methods: A 96-year-old male presented with 1.2 cm by 1.5 cm tumoral lesion with an ill-infiltrated border and central ulceration located on the mid right lower leg. Biopsy confirmed the diagnosis of squamous cell carcinoma (SCC) in situ. The primary lesion was treated centrally to peripherally with multiple intralesional injections of 1.5 mL 5-Fluorouracil (5-FU) (50 mg/mL). The lesion was also treated with a single layer application of 80% Trichloroacetic acid (topical solution). One additional and final treatment of only 80% TCA was performed after three weeks.Results: There was a complete regression of the SCC three weeks after the second treatment.Conclusions: We demonstrate a case of SCC successfully treated with intralesional 5-FU and topical Trichloroacetic acid. Additionally, the SCC in situ was successfully cleared in two treatment sessions with the lowest cumulative dose of 5-FU reported. Intralesional injections of 5-FU and subsequent topical Trichloroacetic acid may be an effective option for patients with SCC who are not eligible for cutaneous surgery.