Non-healing, non-tender ulcer on shin
Our patient’s history provided 2 important clues (one vascular, one not) to explain the painless ulcer that had been on his right shin for a year. A punch biopsy made the diagnosis clear.
Ulcerating BCC can mimic other types of leg ulcers
The differential diagnosis of a chronic leg ulcer includes venous or arterial ulcers, malignancies (SCC, BCC, lymphoma, melanoma), infectious ulcers (bacterial, deep fungal), pyoderma gangrenosum, and traumatic or factitial wounds (TABLE).1,4,5,8,9
Consider biopsy for ulcers that don't respond to treatment
The diagnosis of BCC in a leg ulcer is confirmed histologically. A punch or incisional biopsy should be taken at the edge of the ulcer, including the base.5,6 (For a Watch & Learn video that demonstrates how to perform a punch biopsy, go to https://bit.ly/punch_biopsy.) Providers may be concerned that biopsies could worsen a chronic wound; however, biopsy sites usually heal with no substantial complications.2,6,7 There are no guidelines on when to biopsy an ulcer, but it is reasonable to biopsy a leg ulcer that has not responded to 3 months of conservative treatment.2,7
Factors associated with malignancy in chronic leg ulcers include older age, abnormal excessive granulation tissue at wound edges, high clinical suspicion of cancer, and number of previous biopsies.7 The size and duration of the ulcer do not directly correlate with malignancy.7 The threshold for performing a diagnostic biopsy in a chronic leg ulcer should be lower for a patient who has any of the risk factors noted above. Be aware that ulcerating skin cancers may lack the classic appearance of typical skin cancers.6
