Correct diagnosis is key to successful treatment. Diagnosis in oncology is based on morphological examination of the tissue sample acquired during biopsy or operation material. However there are situations when morphological examination of tumor tissues is not in concordance with clinical data, pathologists conclusion is not equivocal or description of tissue sample does not provide treating doctor with sufficient information about tumor. Then following steps might be necessary:

- repeated review of the sample with adding necessary morphological information (second opinion)

- more profound investigation of the sample with immunochemical tissue stains;

- investigation of genetic material in tumor tissues.