Multiple interchanging of tissue samples in cases of breast cancer

Due to the suspicion of a gynaecologist, a pathologist was suspected of incorrect diagnoses in cases of breast cancer and the interchanging of tissue samples. Many women applied to the attorney's bureau to clarify the reproaches. The privately owned laboratory for pathology was searched and 926 histological slides, roughly the same number of paraffin blocks and about 20 formalin fixed tissue samples were confiscated. Together with other confiscated material, at least 1236 histological slides and additional 249 paraffin blocks had to be sorted. Histological slides and paraffin blocks were matched with patients as far as possible following the laboratory book. Many of the warranted samples which were diagnosed as containing the carcinoma by the pathologist were missing. A total of 160 samples were chosen and rediagnosed by two independent pathologists. The formalin fixed tissue was negative for DNA most likely due to storage in formalin for years. Most of the histological slides were positive for DNA. On the whole, 18 expertises about histological findings and the DNA results were given. In some cases only DNA results could be presented, as previous experts had only performed DNA examinations without controlling the histological diagnosis. In six cases a carcinoma could be confirmed and the DNA profile matched with patient's DNA; in seven cases a carcinoma was confirmed without match with the patient; in two cases the carcinoma could not be confirmed in the presented samples. A jurisdictional solution was impossible because the accused pathologist died during the investigation. In conclusion, it must be stated that a DNA examination of histological slides should never be performed without a rediagnosis of an independent pathologist and photographic documentation of the findings. Whenever possible, material should be left on the slide.