Sclerosing Stromal Tumor of the Ovary in Postmenopausal Women : A Report of Two Cases

C l i n M e d International Library Citation: Lee CM, Lim S, Cho HY, Ha SY, Shin JW (2015) Sclerosing Stromal Tumor of the Ovary in Postmenopausal Women: A Report of Two Cases. Obstet Gynecol Cases Rev 2:045 Received: April 29, 2015: Accepted: June 16, 2015: Published: June 19, 2015 Copyright: © 2015 Lee CM. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Lee et al. Obstet Gynecol cases Rev 2015, 2:4


Introduction
Sclerosing stromal tumor (SST) is a rare benign ovarian neoplasm of the sex cord stromal category first delineated as a distinct ovarian sex cord stromal tumor entity in 1973 by Chalvardjian and Scully [1].Most patients afflicted with SST present with nonspecific symptoms related to an adnexal mass.The tumor, with rare exceptions, is hormonally inactive.Diagnosis of SST can be confirmed by postoperative pathologic examination.It is important to perform differential diagnoses of SST relative to other sex cord stromal tumors including fibroma, thecoma and lipoid cell tumors [2].It is distinguished from other ovarian stromal tumors by the production of collagen, a pseudolobular pattern, and it tends to occur in the second and third decades of patient life [3].
Herein, we present two cases of SST occurred in postmenopausal women with brief review of literature.

Case 1
A 63-year-old postmenopausal woman, gravida 5, para 2, experienced lower abdominal discomfort accompanied by a palpable abdominal mass for one month prior to her visit.Physical examination revealed a solid, non-tender tumor palpable up to the umbilicus level, and pelvic ultrasonography revealed a welldefined 14cm sized heterogeneous, predominantly cystic pelvic mass with solid portions.A computed tomography (CT) scan of the abdomen and pelvis revealed a 15cm sized tumor with an enhancing showing a diffuse hemorrhagic, variegated appearance.The cystic contents included dark brown serous fluid, blood clots and necrotic tissue.The solid components were white to yellow and fibrotic in appearance (Figure 2).
Microscopically evaluated, the solid area showed a pseudolobular pattern alternating between hypercellular and hypocellular areas (Figure 3a).The cellular areas were composed of dual cell populations: collagen-producing spindle cells and rounded weak lutein cells (Figure 3b).The results of the immunohistochemistry (IHC) assessment included Inhibin α: Focal positive, Calretinin: Positive, Smooth muscle actin: Positive, Desmin: Focal weak positive and CD34: Negative.The pathological diagnosis was SST of the left ovary.

Discussion
SST of the ovary is a distinct ovarian stromal tumor subtype [4].Ovarian SST most commonly occurs during the second to third decades of life at an average age of diagnosis of 27.5 years.More than 80 % of SST cases occur in patients under 30 years of age [5].It is rare that SST is diagnosed in postmenopausal women, however, recently it has been reported that a 80-year old woman had SST.I t is far more difficult to diagnose SST in elderly women for many reasons; the incidence is much lower in elderly women, symptoms related to menstruation cycle can be hidden due to patients' menopause, and various common conditions can cause non-specific abdominal pain in senior populations [6].
In children and adolescents, symptoms include premature menarche, menstrual irregularities, abdominal discomfort/pain, and rarely, ascites [6].In post-menarcheal females, SST presents with menstrual irregularities and/or an abdominal mass.In our cases, the patients presented with abdominal pain and a palpable mass.SST sizes vary from 1.5 to 20cm in diameter [5].
In patients with SST, serum CA-125 levels have been found to be either elevated or within reference ranges [7].The tumor in SST cases is usually hormonally inactive, although cases accompanied by irregular menses and genital bleeding have been reported.Peng et al. found 114 SST cases reported through 2003 [4].In our two cases, we observed normal serum hormone levels with no clinical virilization.One patient's blood tumor marker was normal while the other was mildly elevated.
The sonographic findings associated with SST include a welldefined solid mass with hyperechoic honeycomb structures, which are also the characteristics of a mixed heterogenecity tumor without focal calcifications [8].
It is difficult to diagnose before surgery by imaging studies.It used be diagnosed by pathological examination during or after surgery.A preoperative diagnosis of SST is possible based on magnetic resonance imaging (MRI) findings that demonstrate pseudolobulation, which consist of low-intensity nodules set against high-intensity stroma on T2-weighted images [9].The presence of tightly packed cellular areas associated with foci of sclerosis justifies the observed low density of these nodules on T2-weighted images.High-intensity areas found on the T2-weighted images correlated with poorly formed cellular tissue that was markedly edematous.However, the differentiation between SST and other stromal tumors and metastatic ovarian tumors based on MRI results needs further investigation.Upon the analysis of dynamic contrast enhanced images, the tumors revealed early peripheral enhancement with centripetal progression.Striking early enhancement reflects the cellular areas with their prominent vascular networks, and an area of prolonged enhancement in the inner portion of the mass represents the collagenous hypocellular area.These findings can be useful in differentiating SST from fibroma, as fibroma produces an absence of early enhancement and delayed accumulation of the contrast material [10,11].A cystic mass with a solid portion revealing a diffuse hemorrhagic, variegated appearance.The cystic contents include dark brown serous fluid, blood clots and necrotic tissue.The solid components were fibrotic and white to yellow in appearance.

ISSN: 2377-9004
Histologically, SST is characterized by cellular heterogeneity, prominent vasculature, and a pseudolobular structure composed of both cellular and hypocellular areas [12].The name "sclerosing stromal tumor" was proposed because the cellular portions of the tumor tend to undergo collagenous sclerosis.SST has occasionally been confused with massive ovarian edema and Krukenberg's tumor [13].The distinction between SST and Krukenberg's tumor can be made using immunohistochemistry staining [4].SST is positive for desmin and smooth muscle action (SMA).Inhibin also has been shown to be positive and be a useful marker for ovarian sex cord stromal tumors [14,15].In addition, both the cellular and edematous areas are positive for vascular endothelial growth factor.Other stromal tumors, i.e. thecoma and fibroma, tend to occur in the fifth and sixth decades of life of afflicted patients [13] whereas almost 80 % of SSTs occur in women under 30 years of age [14].
While most cases of SST have been reported to occur in the second and third decades of life, in this report, we present two cases of SST in postmenopausal women.We expect that this report will be helpful in the differential diagnosis of future SST cases that may occur in atypical patient populations [16,17].