Before the advent of modern study of pigment,1 in which the dopa reaction of Bloch and the silver nitrate reaction for darkening melanin are the most essential methods, it was difficult to diagnose many dermatoses characterized predominantly by abnormality of melanotic pigmentation. Since that time many conditions have been more or less satisfactorily evaluated as far as the actual pigmentary process is concerned. The underlying etiologic mechanism may, however, defy all efforts at solution. There are still unusual pigmentary dermatoses which for the very reason of their rarity have not been observed frequently enough to establish their nature. It is only after such a condition has been reported by several observers that it is eventually pigeonholed for future reference. Such a condition was recently studied by us, which, owing to its rarity and interesting features, was deemed worthy of report. REPORT OF THREE CASES Three sisters, 1 aged 47