Finally, a long-standing lupus, especially on the cheek, may become the
seat of epithelioma--_lupus epithelioma_--usually of the exuberant or
cauliflower type, which, like other epitheliomas that originate in scar
tissue, presents little tendency to infect the lymphatics.
The _diagnosis_ of lupus is founded on the chronic progress and long
duration, and the central scarring with peripheral extension of the
disease. On the face it is most liable to be confused with syphilis and
with rodent cancer. The syphilitic lesion belongs to the tertiary
period, and although presenting a superficial resemblance to
tuberculosis, its progress is more rapid, so that within a few months it
may involve an area of skin as wide as would be affected by lupus in as
many years. Further, it readily yields to anti-syphilitic treatment. In
cases of tertiary syphilis in which the nose is destroyed, it will be
noticed that the bones have suffered most, while in lupus the
destruction of tissue involves chiefly the soft parts.
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