Vulvar cancer in hidradenitis suppurativa.

Background: Hidradenitis suppurativa (HS) is a debilitating disorder characterized by chronic inflammation in intertriginous areas. Malignant transformation to squamous cell carcinoma (SCC) is rare and is mostly diagnosed in the perianal area in men. The clinical behavior of SCC in HS can be aggressive, with local invasion and distant metastases.Case descriptions.We describe two cases of vulvar SCC in HS. The first demonstrates a 75 year old woman with a severe undertreated HS for over 30 years, who presented with a widespread vulvar cancer with lymphangitis carcinomatosa and inguinal and pelvic lymphadenopathy within several weeks after first suspicion of a malignancy. She died shortly after diagnosis. The second case describes a 61 year old woman diagnosed with HS 7 years ago, who presented with a rapidly progressive vulvar cancer with suspicion for ingrowth in the anal sphincter, vagina and levator ani muscle with inguinal and pelvic lymphadenopathy. She received radical chemoradiation with a complete response on imaging, but had a local recurrence within 2 months after finishing treatment. A posterior exenteration was performed but 5 months after surgery she had a second recurrence in the vulvar scar and pelvic floor muscles with possible bone metastases. She received palliative chemotherapy.

Conclusion: Vulvar SCC in an area of HS is a rare condition which is difficult to diagnose. It can have an aggressive course with rapid progression and a high frequency of metastases at presentation. Early surgical excision of HS to diagnose occult malignant transformation, appropriate imaging to establish the extent of the disease and an aggressive treatment plan without any delays are recommended.