Although rarely mentioned in differential diagnosis, the mouth of a fistula may so resemble a cutaneous cancer as to deceive one into treating it as such. The following cases illustrate this fact.
REPORT OF CASES
Recently a man was referred to me for treatment for what was thought to be an intractable epithelioma of the chin, for which he had been previously treated unsuccessfully by another physician. At the bottom of a deep conical hollow at the tip of the chin, exactly in the place where a dimple frequently occurs, was a small ulcer resembling an epithelioma. The patient said that eight months previously it had swollen and had discharged a quantity of pus and that it had been growing larger and deeper ever since. This should have put me on the alert, but its appearance, its course and its long endurance seemed to leave no doubt of
Montgomery DW. FISTULAS FROM DEAD TEETH SIMULATING DERMAL EPITHELIOMA. Arch Derm Syphilol. 1940;41(2):378–379. doi:10.1001/archderm.1940.01490080187011