Invasive squamous cell carcinoma after treatment of carcinoma in situ with 5% imiquimod cream

Abstract

Squamous cell carcinoma in situ has the potential to progress to invasive squamous cell carcinoma. This report presents two cases of punch biopsy-proven squamous cell carcinoma in situ, treated with once-daily application of 5% imiquimod cream for 6 weeks. Both patients developed moderate local inflammatory reactions during treatment. The first patient demonstrated clinical clearance of the scalp lesion after treatment. Two months later, he re-presented with a subcutaneous nodule at the same site. Histology was consistent with recurrent squamous cell carcinoma. Five months following excision of the recurrent tumour, he presented with metastatic squamous cell carcinoma to a cervical lymph node. The second patient had low-grade chronic lymphocytic leukaemia and presented with squamous cell carcinoma in situ of the leg that failed to clear clinically after treatment with imiquimod. He presented 4 months later with a focus of invasive squamous cell carcinoma within the lesion.

Therapeutic options for Bowen’s disease

“…Successful treatment of anogenital Bowen's disease with imiquimod has also been reported 98,99. Two cases of invasive SCC arising from Bowen's disease of the scalp and legs have been reported after treatment with imiquimod 100. …”

Bowen′s disease on finger: A diagnostic and therapeutic challenge

“…The histological evaluation of the excised specimen revealed invasive squamous cell carcinoma (SCC) invading the bone. Similarly, Goh [19] and Murphy et al [20] have described cases in which Bowen's disease initially responded to imiquimod but recurred as SCCs which were treated with complete excision without recurrence.…”

Diagnosis and treatment of Bowen’s disease

“…Successful treatment of anogenital BD with imiquimod has also been reported [92]. However, two cases of invasive SCC arising from BD have been reported after treatment with imiquimod [93].…”