Squamous cell carcinoma arising in long-standing hidradenitis suppurativa: An overlooked facet of the immunocompromised district.

The list of comorbidities and complications associated with hidradenitis suppurativa is extensive. Among the complications of hidradenitis suppurativa, squamous cell carcinoma is considered the most severe. After a meticulous literature research starting from the 1950s, we were able to identify over 90 cases of patients with hidradenitis suppurativa developing squamous cell carcinoma. Most squamous cell carcinomas appear on the perineal or buttock areas. We believe that the development of squamous cell carcinoma in longstanding hidradenitis suppurativa is a typical condition of an immunocompromised district. The "immunocompromised cutaneous district" is a novel concept that applies to an area of diseased or injured skin where local immune control has been altered, thereby permitting the development of a dysimmune reaction, infection, or tumor confined to the diseased or injured site.