Differential diagnosis of soft scalp lumps.

A 56-year-old man presented with a painless cyst on the top of his head which has been increasing in size in the last 6 months. Due to his learning disability, he could not be dissuaded from his belief that the lump was a sign of brain prolapse which led to increasing agitation in the next 2 weeks. A provisional diagnosis of benign lipoma was made and prompt excision was performed in his best interests. The lesion was more cystic and fluctuant than that of a lipoma and hence it was sent for histological diagnosis. The report came back as a trichilemmal cyst with no signs of proliferation. Cosmetic outcome was reasonable at follow-up after 3 months. The patient was scheduled for regular review every 6 months.