Mondor's disease of the breast resulting from jellyfish sting. 
To present two cases of Mondor's disease of the breast resulting from jellyfish stings in Western Australia.  A 30-year-old Caucasian woman presented with a palpable thickened cord in her right breast.  The straightness of the cord suggested a thrombosed lymphatic.  A 50-year-old Caucasian woman presented with an obvious palpable cord extending most of the length of her left breast.  Mammography demonstrated no abnormality.  Both women reported having been stung by jellyfish a month earlier.  As Mondor's disease is a benign, self-limiting disease, the patients were reassured and reviewed routinely.  In each case, the condition settled spontaneously over a period of several weeks.  Jellyfish stings should be recognised as an unusual variant of the numerous causes which have been described for Mondor's disease.