For small localised plaques and tumours, treatment with low energy photons are adequate. PTV = GTV + 0.5 to 1 cm margins; margins tend to be smaller as these patients are often retreated.
8 Gy in 2# or 12 Gy in 3#, treating daily
For a larger or thicker tumour or collection of plaques, and particularly if the area is over a joint consider treatment with electrons.
20 Gy in 5# over 1 week or 30 Gy in 10# over 2 weeks.