Introduction/Background So-called tuft cell variant of small cell carcinoma is now a well-established subset of small cell carcinomas of the lung, driven by POU2F3 transcriptomic factor, and characterized by low or no expression of neuroendocrine markers.

Methodology We report here the case of a POU2F3 driven subset of small cell carcinoma of the uterine cervix, in a woman in her early 40s. This HPV-dependent carcinoma was clinically considered as primary. Immunohistochemistry and RNA-sequencing with expression and clustering analyses were performed.

Results The biopsy showed typical morphological features of small cell carcinoma. Immunohistochemistry showed no neuroendocrine markers (chromogranin A, synaptophysin) expression, but a clear POU2F3 nuclear expression, similar to that of the tuft cell variant of lung small cell carcinoma. Clustering analysis of expression data obtained by RNA-sequencing revealed an expression profile similar to that of POU2F3 driven small cell lung carcinomas.

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Abstract 2022-RA-681-ESGO Figure 1

Conclusion This variant has never been reported in uterine cervix and is worth recognizing since these tumours are usually negative for neuro-endocrine markers, and thus present a diagnostic challenge. If small cell carcinoma is first and foremost a morphological diagnosis, the use of POU2F3 imunohistochemistry as a novel diagnostic marker for these tumours with negative or low expression of neuro-endocrine markers could be helpful in clinical practice, especially on small cervix biopsy samples.