Topical Treatment of Cutaneous Squamous Cell Carcinoma in Situ and the Impact of Clinical Risk Factors and Positive Histologic Margins at the Time of Diagnosis.

BACKGROUND: Limited data exist for the efficacy of topical 5-fluorouracil (5-FU) and imiquimod for cutaneous squamous cell carcinoma (cSCC) in situ (cSCCis) with positive histologic margins at the time of diagnosis. OBJECTIVE: Identify the efficacy of topical 5-FU and imiquimod in the treatment of cSCCis with positive histologic margins at the time of diagnosis in relation to clinical risk factors. MATERIALS AND METHODS: Pathology records were screened at a single institution from 2014 to 2021 for cSCCis with positive histologic margins. Patients were included if they were treated with curative intent with topical 5-FU or imiquimod. Recurrences were evaluated in relation to multiple clinical risk factors. RESULTS: Of 215 patients treated with 5-FU or imiquimod after biopsy-proven cSCCis, 19 patients had recurrent cSCCis and 1 patient had upstaging to invasive cSCC. Recurrence was more likely in larger lesions at the time of initial biopsy ( p = .033) and in patients treated with topical imiquimod compared with topical 5-FU ( p < .01). CONCLUSION: Topical 5-FU is an appropriate therapy for cSCCis in the correct clinical scenario. Extra consideration should be taken for use of 5-FU in larger diameter cSCCis lesions. Although limited by sample size, our study does not support the use of imiquimod for cSCCis.

Eccrine porocarcinoma presenting as a recurrent wart.

Eccrine porocarcinoma (EPC) is an exceedingly rare sweat gland tumor most commonly seen in older patients. Diagnosis of EPC is rare, representing a small percentage of cutaneous malignancies. In the absence of established guidelines, wide local excision (WLE) has traditionally been considered the standard treatment. However, there is growing evidence of increased local recurrence and nodal metastasis associated with WLE. More recently, Mohs micrographic surgery (MMS) is emerging as an effective treatment method with higher cure rates. We report a case of EPC presenting as a recurrent wart in a 36-year-old man that was successfully treated with MMS.