Diagnosis of multiple familial trichoepithelioma is made based upon the clinical symptoms in the patient, the patients family history, and the appearance of the trichoepithelioma cells under a microscope (histology). Multiple familial trichoepithelioma must be distinguished from basal cell carcinoma (cancerous tumor) and other rare genetic syndromes such as Cowden syndrome. 
How to diagnose Multiple familial trichoepithelioma ?