Microcystic Stromal Tumor with Predominant Bizarre Nuclei of Ovary in a Pregnant Woman

Figure 2

Microcystic stromal tumor (MST) of the ovary. (a) Solid nodule with infiltrative border, separate from a mucinous cyst (asterisk) by thick fibrous stroma (H&E, 1.25×). The cyst is lined with benign mucinous epithelium (inset) (H&E, 20×). (b) The irregular infiltrative-like border of MST (H&E, 10×). (c) Solid pattern with microcysts of variable caliber and the diffuse presence of bizarre cells. Large spaces containing blood and fibrin are also observed (H&E, 10×). (d) Bizarre cells with epithelioid features and pleomorphic hyperchromatic nuclei (H&E, 40×). (e) Aggregates of signet ring-like cells (H&E, 40×). (f) Typical MST features of cellular areas with hyalinized fibrous bands (H&E, 10×). Monotonous tumor cells with bland nuclei punctuated by relatively uniform microcystic spaces (inset) (H&E, 40×).

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