Diffusion-Weighted MRI and FDG-PET in Diagnosis of Endometrial Stromal Nodule

Abstract

Preoperative differentiation of benign endometrial stromal nodule (ESN) from malignant low-grade endometrial sarcoma (LGESS) is challenging, because it requires histological evaluation of the tumor-myometrium interface, which is difficult to obtain in conventional endometrial curettage. A 72-year-old postmenopausal woman presented with 5-year history of persistent vaginal bleeding. Histological examination of the endometrial curettage specimen revealed hyperplasia of apparently normal endometrial stromal cells. T2-weighted magnetic resonance imaging (T2W-MRI) showed polypoid tumor occupying the entire uterine cavity. The tumor exhibited high signal intensity in diffusion-weighted MRI (DW-MRI) and intense accumulation of 18F-fluorodeoxyglucose (FDG) in positron emission tomography (PET). Intense FDG accumulation was also observed in the left internal iliac region. Total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymphadenectomy were performed under the diagnosis of LGESS with lymph node metastasis. However, postoperative histological examination proved that the tumor was ESN without lymph node metastasis. Since mitotic figure is no longer included in the diagnostic criteria of ESN or LGESS, ESN could exhibit high cellularity and high proliferative activity as observed in this case. Therefore, DW-MRI or FDG-PET is not useful in the differentiation of ESN from LGESS.

Magnetic resonance imaging of an endometrial stromal nodule

“…In the present case, the inhomogeneous hyperintensity of the mass on T2‐weighted images mimicked a feature of the endometrium, and this mass corresponded histologically with proliferating endometrial stromal cells. This finding is similar to that described in a previous report . Stromal cell proliferation was mainly observed in the marginal area, and this histological finding correlated with enhancement in the dynamic contrast study.…”

“…[ 18 F]‐Fluorodeoxyglucose emission tomography is also useful in some cases; however, neither examination was performed in the present case. Notably, in a previous case, neither diffusion‐weighted imaging nor [ 18 F]‐fluorodeoxyglucose positron emission tomography was useful for differentiating an endometrial stromal nodule from low‐grade endometrial stromal sarcoma …”

“…If present, infiltration generally appears as 1‐3mm sized protrusions . Several reports have described the pathological features of endometrial stromal nodules . However, the characteristic magnetic resonance (MR) imaging appearance of this rare tumor type has not been established; therefore, it is difficult to make a preoperative diagnosis.…”

Endometrial stromal nodule: report of 8 cases and literature review

“…These findings were similar to those de scribed in the previous reports. For instance, Maruyama et al presented a case of benign ESN that showed high sig nal intensity in diffusionweighted images [26] and Ozaki and Gabata found that the observed hyperintensity on T2 weighted images, similar to that of the endometrium, and the well circumscribed margin, seemed to suggest an en dometrial stromal nodule [27]. Nevertheless, it is dis appointing that the present results indicated that serum biomarkers could not provide valid help for clinicians in diagnosing ESN.…”

Analysis of diagnosis and treatment of complicated cervical severe adhesion atresia after removal of endometrial stromal nodule

“…[ 5 ] Even with more advanced methods such as diffusion-weighted magnetic resonance imaging or 18-fluorodeoxyglucose positron emission tomography, ESN presents no validated differences. [ 6 ] Therefore, preoperative diagnosis of ESN is very difficult. ESN is often misdiagnosed as endometrial interstitial ectopic, stromal hyperplasia, or uterine fibroids.…”