ABSTRACT
Porphyrias are metabolic disorders of heme biosynthesis, which encompass a broad range of symptoms and signs, neurologic, cutaneous or mixed. Because of lack of specificity and polymorphous clinical picture, porphyrias can mimic either neuropsychiatric, dermatologic, or gastrointestinal diseases. We present the case of a 58 years old man to whom clinical presentation suspicious of Addison's disease (melanoderma, fatigue, weight loss, intermittent abdominal pain) was the disguise of porphyria cutanea tarda. A general background of porphyrias and differential diagnosis with other forms of hepatic porphyria, as well as other causes of hyperpigmentation, are given. The clinician should be aware of the protean manifestations of porphyrias and include them in clinical judgment in various situations.