LAUSR

Background Primary ovarian mucinous tumors with mural nodules are very rare. The histogenesis of the mural nodules remains unclear. Methods We investigated the clincopathological and molecular features in 3 cases with mural nodules. Results Patient 1 was diagnosed as mucinous carcinoma with mural nodules of anaplastic carcinoma that was composed of CK+ and CK7+ spindled cells and polygonal cells with marked pleomorphism. Aberrant p53 staining was found in the mural nodules rather than in the mucinous components. A concordant KRAS mutation (c.35G > A p.G12A) was identified in both mucinous tumors and mural nodules. She died of disease at 44 months. The mural nodule in patient 2 was interpreted as a sarcoma, no other specified. The uniform short spindle cells were separated by abundant myxoid matrix. They were CD10 + , CCND1-, SMA-, and negative for break-apart BCOR , PHF1 , and JAZF1 FISH assay. The adenocarcinomatous component harbored LOH at D18S51 and FGA loci while the sarcomatous component had LOH at D19S433 . She had lung metastasis at 18 months and was alive without evidence of disease for 40 months. Patient 3 harbored multiple mural nodules that were composed of vimentin+, focal CK+, atypical spindle cells. A diagnosis of sarcoma-like mural nodules was rendered. She was alive with no evidence of disease for 13 months. No hotspot mutant AKT1 , KRAS , HRAS , and PI3KCA alleles were found in patients 2 and 3. Conclusions Mural nodules with anaplastic carcinoma or with true sarcomas may represent the dedifferentiation form of mucinous tumors or collision tumors, respectively. The worrisome histology in sarcoma-like mural nodules necessitates meticulous treatment for these patients.