Abstract
BACKGROUND: Low-grade endometrial stromal sarcoma (ESS) is rare mesenchymal neoplasm, recently specified as harboring JAZF1-SUZ12 rearrangement. Typical JAZF1-SUZ12 ESS is slow growing, in which high uptake of fluorodeoxyglucose (FDG) on positron emission tomography (PET) and subserosal masses are quite unusual. CASE PRESENTATION: A 69-year-old Japanese woman complained of urinary incontinence. Pelvic magnetic resonance imaging showed uterine lesions composed of (1) a 9 × 8 × 7-cm mass protruding from the right-anterior wall, (2) a 4.5-cm mass attached to the right-posterior wall, and (3) a 6.5-cm intramural mass in the fundus. FDG-PET demonstrated maximum standardized uptake value of 13.28 confined to the two subserosal masses (1 & 2) in contrast to no uptake of the intramural mass (3). She was diagnosed with a high-grade uterine sarcoma concomitant with leiomyomas and underwent total hysterectomy with bilateral salpingo-oophorectomy and pelvic lymphadenectomy. The removed uterus had three tumors-two in the right-anterior and right-posterior subserosa, respectively, and the remaining in the fundal myometrium. Microscopically, the three tumors shared morphologic features characterized by neoplastic cells similar to proliferative-phase endometrial stromal cells, in which neither round-cell component, pleomorphism, nor high mitotic activity was recognized. Nuclear cyclin D1 immunostaining was identified 50% of neoplastic cells in the two subserosal tumors (1 &2) whereas < 1% positive cells in the intramural component (3). Reverse transcriptase-polymerase chain reaction showed the same-sized electrophoretic bands indicating JAZF1-SUZ12 gene fusion shared by the three uterine tumors and a focal tumor extension into the extrauterine vein. The patient is alive without evidence of recurrence at 14 months after surgery. CONCLUSIONS: Pathologists and clinicians should not exclude the possibility of JAZF1-SUZ12 ESS even when uterine subserosal masses demonstrate extraordinary FDG uptake on PET. Molecular analysis is helpful for diagnostic confirmation of JAZF1-SUZ12 ESS with a complex growth pattern.