Cutaneous Squamous Cell Carcinoma in Patients with Hidradenitis Suppurativa

SIMPLE SUMMARY: Cutaneous squamous cell carcinoma (cSCC) is a recognized but infrequent complication of hidradenitis suppurativa (HS). After performing a thorough literature review of all the published cases of cSCC developing in HS, we identified that White males who are smokers and afflicted with severe gluteal or perianal HS are more likely to develop cSCC. Human papillomavirus (HPV) was found to be a common co-factor. cSCC of ulcerative morphology with a poorly differentiated histologic grade, the presence of nodal or distant metastasis, and recurrent cSCC were associated with decreased survival. Regular screening of suspicious lesions for detection of cSCC in patients with HS, notably those with the aforementioned demographics, is highly recommended. ABSTRACT: Background: Cutaneous squamous cell carcinoma (cSCC) is a rare complication of hidradenitis suppurativa (HS). Objectives: To conduct a systematic review and an individual patient data (IPD) meta-analysis to describe the clinical characteristics of HS patients developing cSCC and determine predictors of poor outcome. Methods: Medline/PubMed, Embase, and Web of Science were searched for studies reporting cSCC arising in patients with HS from inception to December 2019. A routine descriptive analysis, statistical hypothesis testing, and Kaplan–Meier survival curves/Cox proportional hazards regression models were performed. Results: A total of 34 case reports and series including 138 patients were included in the study. The majority of patients were males (81.6%), White (83.3%), and smokers (n = 22/27 reported) with a mean age of 53.5 years. Most patients had gluteal (87.8%), Hurley stage 3 HS (88.6%). The mean time from the diagnosis of HS to the development of cSCC was 24.7 years. Human papillomavirus was identified in 12/38 patients tested. Almost 50% of individuals had nodal metastasis and 31.3% had distant metastases. Half of the patients succumbed to their disease. Conclusions: cSCC is a rare but life-threatening complication seen in HS patients, mainly occurring in White males who are smokers with severe, long-standing gluteal HS. Regular clinical examination and biopsy of any suspicious lesions in high-risk patients should be considered. The use of HPV vaccination as a preventive and possibly curative method needs to be explored.