Metastatic colorectal adenocarcinoma in cervicovaginal cytology specimens confirmed by immunocytochemical stains on liquid base specimens: Two study cases with review of the literature
Recently, two Pap smears were interpreted as positive for malignant cells in LBC TP smears, consistent with ACA, possibly metastatic.\nThe first patient was an 82-year-old female with a history of hysterectomy and colon cancer, status postpartial colon resection who presented with vaginal bleeding. The second patient was a 56-year-old female with a history of invasive ACA of the rectosigmoid colon, status-post segmental resection who presented for routine examination.\nThe LBC of vaginal specimens from both patients were received in PreservCyt fixative, processed by TP 2000 automated processor (Hologic Inc., Bedford, MA) and stained by modified Papanicolaou stain.\nIn the first case, the TP Pap smear preparation was moderately cellular and showed clusters and groups of columnar-shaped tumor cells with enlarged ovoid nuclei, an increased nuclear-to-cytoplasmic ratio, marked nuclear pleomorphism, hyperchromasia, and nucleoli in some of the cells. Mixed inflammatory cells and squamous cells were present in the background []. In the second case, the TP Pap smear showed tumor cells present in syncytial fragments of tumor cells with enlarged ovoid nuclei, increased nuclear to cytoplasmic ratio, nuclear pleomorphism, hyperchromasia, and prominent nucleoli [].\nFor the first case, further evaluation with ICC was not possible for confirmation of the primary tumor due to the lack of sufficient material. In the second case, the residual LBC specimen was utilized to prepare additional TP slides for ICC. The ICC stains for cytokeratin 7 (CK7), CK20, and caudal-related homeobox 2 (CDX2) were performed on the Ventana Bench Mark Automated stainer utilizing commercial pre-diluted antibodies and protocol previously described.[] ICC stain was considered positive when more than 5% of the tumor cells showed immunostaining. For the second case, ICC showed immunoreactivity in the tumor cells for cytoplasmic CK20 and nuclear CDX2, while the tumor cells were non-immunoreactive for CK7 [].\nConcurrent vaginal biopsy results were used for confirmation in both cases. The vaginal biopsies showed metastatic colorectal carcinoma infiltrating the vaginal tissue []. The immunohistochemical stains performed on the vaginal biopsies supported the diagnosis of metastatic ACA of colorectal origin consistent with the clinical history of colon carcinoma. The material from the primary colorectal carcinoma from case 1 was available for review and showed morphology similar to that seen in the vaginal biopsy.