Ovarian microcystic stromal tumor with undetermined potential: case study with molecular analysis and literature review.

Ovarian microcystic stromal tumor is a relatively rare tumor type. This tumor is characterized by a unique microcyst structure, and essentially all tumors show benign biological behavior. Here, we report a case with a primary ovarian microcystic stromal tumor that experienced recurrence. Pathological findings showed that the original tumor, relapsed tumor in the ovary, and the recurrent tumor in the iliac fossa presented similar histologic features. The tumor mainly consisted of microcysts, solid cellular regions, and a fibrous stroma. Immunohistochemically, the tumor cells were positive for β-catenin, CD10, vimentin, and WT-1. Mutational analysis revealed a missense mutation (c.1590C>T; pG530E) in exon 15 of the APC gene and another missense mutation (c.740G>A; pA247V) in exon 1 of the KRAS gene. We also reviewed other published cases to evaluate the prognosis and treatment. This is the first report to describe a microcystic stromal tumor of the ovary presenting with undetermined biological potential.