Mondor's disease is a rare, benign condition characterised by thrombophlebitis affecting subcutaneous veins of the chest and/or abdomen without an accompanying inflammatory response. The disease has a multifactorial etiology and its course is benign. It is usually self-limiting or it is eliminated by local treatment. Mondor's disease in the thoracoepigastric region may be a rare complication of mammotome biopsy. The case presentation describes a 32-year-old patient with Mondor's disease in the thoracoepigastric region after an ultrasound-guided mammotome biopsy of a breast. In the histopathological examination the lesion was diagnosed as fibroadenoma. Regardless of the disease's etiology, it is recommended to carry out diagnostic examinations to exclude co-occurring breast cancer