case_images: PMC11361924_01
case_images: (A) The ovarian cyst wall was lined with a single layer of mucinous columnar epithelium, with no significant cellular atypia observed. (B) The mucous epithelial cells exhibit a benign morphology, with nuclei located at the basal portion and the cytoplasm rich in mucus (C) Mural nodules were present beneath the mucinous epithelium, with unclear boundaries between the nodules and the surrounding tissues. (D) The mural nodules consisted of spindle cells, pleomorphic cells, and a few adipocytes. The adipocytes showed good differentiation and varied in size. (E) Under high magnification, the spindle cell nuclei exhibited significant atypia, with abundant and eosinophilic cytoplasm, and the tumor stroma demonstrated prominent hyaline degeneration. (F) Scattered giant tumor cells were visible. Lymphocyte and plasma cell infiltration and lymphoid follicle formation were noted in the stroma. (G) Tumor cells invaded large blood vessels. (H) Tumor cells grew around nerves. (I) Under high magnification, fat cell nuclei showed mild atypia, with a few visible lipoblasts. (J) Adipocytes showed good differentiation and varied in size. Localized nuclei exhibited mild atypia, and lipoblasts were visible. The black arrows in both I, J indicate lipoblasts.
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case_images: PMC11361924_01_fonc-14-1436854-g001.jpg
case_images: f1
case_images: The ovarian cyst wall was found to be lined with a single layer of gastrointestinal-type mucinous columnar epithelium ( Figure 1A ), showing no papillary hyperplasia. The mucinous epithelial cells exhibited no atypia, with nuclei located at the basal portion and the cytoplasm rich in mucus ( Figure 1B ). This nodule was composed of short spindle cells, pleomorphic cells, and a few adipocytes ( Figure 1C ). Under low magnification, the spindle tumor cells were indistinguishable from the surrounding tissue and were arranged in sheets or bundles ( Figure 1C ). A few adipocytes were scattered between the spindle cells; they showed good differentiation and varied in size ( Figure 1D ). Under high magnification, the spindle cell nuclei clearly exhibited atypia, with abundant and eosinophilic cytoplasms ( Figure 1E ). Figure 1F ). Furthermore, some regions demonstrated signs of tumor invasive growth, including large blood vessel invasion ( Figure 1G ) and perineural growth ( Figure 1H ). The nuclei of adipocytes showed mild atypia under high magnification, with a few visible lipoblasts ( Figures 1I, J ). In the tumor, interstitial collagen markedly degenerated, accompanied by extensive lymphocytic and plasmacytic infiltration; in some regions, lymphoid follicles formation was noted ( Figure 1A ).
case_images: (A) Mucinous epithelium expressed cytokeratin, whereas tumor cells in mural nodules did not. (B) Mural nodules showed a diffuse strong positive expression of vimentin, whereas mucinous epithelium did not. (C) Spindle cells and adipocytes in mural nodules exhibited a strong positive expression of CDK4. (D) Spindle cells and adipocytes in mural nodules expressed MDM2. (E) Spindle cells and adipocytes in mural nodules exhibited a strong positive expression of P16. (F) Spindle cells in mural nodules expressed SMA.
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case_images: f2
case_images: In immunophenotyping, the mucinous epithelium expressed cytokeratin ( Figure 2A ) but not vimentin ( Figure 2B ). Conversely, the mural nodule tumor cells did not express cytokeratin ( Figure 2A ) but exhibited diffuse strong positive expression of vimentin ( Figure 2B ). Additionally, the tumor cells in the mural nodule showed a strong positive expression of MDM2 ( Figure 2C ), CDK4 ( Figure 2D ), P16 ( Figure 2E ), MUC4, and SMA ( Figure 2F ), with a Ki-67 proliferation index of 30%.
case_images: FISH testing revealed CDK4
  (A) and MDM2
  (B) amplification in mural nodules.
case_images: fonc-14-1436854-g003.jpg
case_images: PMC11361924_01_fonc-14-1436854-g003.jpg
case_images: f3
case_images: No definite neoplastic necrosis was observed, and the mitotic figures were approximately 3/10 HPF (high-power fields). CDK4 ( Figure 3A ) and MDM2 ( Figure 3B ) genes. Combining the histological morphology, immunohistochemistry, and MDM2/CDK4 FISH test results, we diagnosed the patient with ovarian mucinous cystadenoma with a mural nodule of well-differentiated liposarcoma, International Federation of Gynecology and Obstetrics (FIGO) stage IA.