The histopathologic diagnosis is the cornerstone of modern oncology. But mix-ups of specimens can occur at any stage. The resection of a 1.2 cm polypoid cervical mass in a 25-year-old woman showed a poorly differentiated adenocarcinoma prospectively staged as T1b1 (International Federation of Gynecology and Obstetrics IB1). Even after complete embedding and serial sectioning of the whole cervix of the hysterectomy specimen after radical hysterectomy, only adenocarcinoma in situ, but no invasive tumor, was seen. To exclude a mix-up of the specimens, identity testing of the paraffin-embedded material was performed by microsatellite analysis. For both materials, we established identical results after testing the microsatellite loci HumTH01, HumVWA, HumFGA, HumACTBP2, HumF13B, and HumD8S1132. The resulting probability of identity came to 99.9999%, excluding a mix-up of the specimens. Archival paraffin-embedded specimens can be used to establish identity and can prevent the wrong patient from having major surgery.