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Exfoliative cytology of invasive neuroendocrine small cell carcinoma in a cervical cytologic smear. A case report.

BACKGROUND
Neuroendocrine small cell carcinoma of the cervix (NSC) is cytologically identical to its counterparts at other sites, such as the lung, and can be suspected on a cervical cytologic smear. It has to be distinguished from poorly differentiated nonkeratinizing squamous small cell carcinoma, adenocarcinoma with carcinoid features, embryonal neuroblastoma, embryonal rhabdomyosarcoma, stromal sarcoma and non-Hodgkin's lymphoma.


CASE
An 18-year-old woman had invasive NSC. Exfoliative cytology of the cervix showed tumor cells, single or in small clusters and files, with darkly staining nuclei. The chromatin pattern was coarse, with small, prominent chromocenters, and the nuclei were often invisible. The cytoplasm was so reduced as to be barely discernible. Mutual molding of adjacent nuclei was frequent. Immunohistochemistry showed positive staining for pancytokeratin and neuron-specific enolase. Flow cytometry showed aneuploidy, with a DNA index of 1.93.


CONCLUSION
The cytologic appearance of NSC in a cervical cytologic smear is characteristic. The diagnosis, nevertheless, has to be proven by the identification of neuroendocrine differentiation.