A leg ulcer may have many causes, including venous stasis, trauma, vasculitis, infection, or (as in this case) squamous cell carcinoma in situ (SCCis), aka Bowen’s Disease.
SCC and SCCis are common skin cancers that occur less frequently than basal cell carcinomas (BCCs).1 SCCis is normally scaly and hyperkeratotic, but it can manifest in rare cases as a chronic ulcer. Fair skin, long history of sun damage, and immunosuppression are significant risk factors for both SCCis and SCC.
While history and other clinical features may help narrow the diagnosis, a wound that does not heal despite treatments should be biopsied. Shave and punch biopsies are both excellent ways to diagnose an SCCis that has a classic appearance. However, ulcers and blisters can be caused by inflammatory processes (as in pyoderma gangrenosum or a fixed drug eruption) with characteristic findings deeper in the dermis; these lesions are better assessed with a punch biopsy.
In this case, a 4-mm punch biopsy was performed at the tissue edge and showed atypical keratinocytes limited to the epidermis. These atypical keratinocytes are associated with vesicle formation and ulcer, consistent with SCCis.
SCCis transforms into invasive disease in 3% to 5% of cases.2 Surgical treatment includes fusiform excision and electrodessication and curettage, both with cure rates that often exceed 90%.2,3 Nonsurgical options include topical 5-fluorouracil (67%-92% effective), topical imiquimod (75%-93%), and photodynamic therapy (52%-98%).4
Treatment choices depend on patient preference and provider capabilities. With surgical options there is the risk of bleeding and the need to care for a healing wound. Nonsurgical treatments can last longer and require topical treatment regimens and medications.
This patient opted for a fusiform excision and linear closure. She will continue to undergo serial skin evaluations twice a year for at least 2 years.
Photos and text for Photo Rounds Friday courtesy of Jonathan Karnes, MD (copyright retained). Dr. Karnes is the medical director of MDFMR Dermatology Services, Augusta, Maine.