Derm Dx: Large oozing plaque on the scalp

An 80-year-old man presents complaining of a very large oozing plaque on his scalp that has been slowly growing for more than a year. He claims that it is not painful, but he is concerned that it is ringworm.

The patient’s past medical history is significant for hypertension and thyroid disease for which he is treated medically. He denies any ...