A summary work presenting technically difficult to process lesion samples and those which cannot be diagnosed on peroperative biopsy. The authors specify arguments against examinations of small mammary gland tumors (measuring less than 1 cm in diameter), post-bioptic tumors and sentinel lymph nodes. Furthermore, the authors describe difficulties in processing the adipose tissue resulting in complicated evaluation of the mammary gland tumors in the resection line. Obstacles in the peroperative examination of the thyroid gland lesions are also listed here. In this case, the freezing technique results in smearing specific cytological featuries of the examined tissue. Diagnostic criteria for all non-papillary tumors of the thyroid gland are explained in this article. Application of the above mentioned criteria is, however, worthless in the peroperative biopsy, which is also explained in this work. In the last part of this study, the authors describe macroscopic featuries of the mucinous ovarial tumors and their differentiation from the gastrointestinal tract adenocarcinoma metastases, using macroscopy and histological techniques.