Sessile serrated adenoma of the appendix coexists with anaplastic carcinoma mural nodules originating from ovarian mucinous tumors: A case report.

Sessile serrated adenomas (SSA) of the appendix and anaplastic carcinoma mural nodules arising in the mucinous ovarian tumors (MOT) are rare lesions. We report a case of SSA in the appendix coexisting with an anaplastic carcinoma mural nodule in MOT. No BRAC1/BRAC2 germline mutations were found in the peripheral blood sample. The paraffin-embedded tissue from normal tissue (as a control), MOT, mural nodule, and SSA of the appendix were separately sequenced by next-generation sequencing (NGS). Based on the NGS results, stop-gain, chromosome DEL or TRA in mural nodules and SSA were detected, which were different from those in the mucinous tumors. In conclusion, we reported a case of SSA in the appendix coexisting with a mural nodule in MOT. We describe the morphological characteristics and molecular detection results in this case. There was no clear genetic evidence of a correlation between these two rare pathological types.