so there have been 50 cases of this rare complication with this type cyst with the type cancer being the squamous cell carcinoma. From my reading about skin cancers--squamous cell is the second most common with the first being basal cell. Squamous cell carcinoma rarely causes further problems when caught and treated early. So I think that if this is something that is at all possible, then you should have your derm look at the area where the cyst was yearly OR if you see any changes.
I know how hard it is not to get upset about the even possiblity of a cancer, but it sounds like this complication is pretty remote. All you can do is be aware of any possible changes and take care of it if it occurs.