Ulceration (melanoma)

Loss of the skin surface over a melanoma under the microscope; a sign of aggressive biology that raises the stage.

Present in roughly a quarter of primary melanomas; independently worsens prognosis and defines the 'b' substage at each T level. Historically predicted benefit from interferon; today it helps define stage IIB/IIC, where adjuvant PD-1 is approved.

Pathology: what this kind of term is about · animated schematic, not to scale