Gonadotropin-releasing hormone receptor expression in endometrial stromal sarcomas: an immunohistochemical study

Gonadotropin-releasing hormone and its receptors have been identified in several human malignancies. We evaluated gonadotropin-releasing hormone receptor expression in 30 primary and recurrent endometrial stromal sarcomas. Archival formalin-fixed and paraffin-embedded material was analyzed immunohistochemically with antisera to gonadotropin-releasing hormone receptor type I and gonadotropin-releasing hormone receptor type II using the peroxidase-antiperoxidase method. Gonadotropin-releasing hormone receptor types I and II were demonstrated in most primary endometrial stromal sarcomas in varying intensity and percentage (range, 10-100%). The staining pattern was either diffuse cytoplasmic or granular/vesicular in perinuclear distribution. Recurrences stained stronger than primary tumors. The demonstration of gonadotropin-releasing hormone receptors I and II expression in endometrial stromal sarcomas may be a rationale for a clinical study of gonadotropin-releasing hormone analogs in the treatment of women with endometrial stromal sarcomas.

Endometrial Stromal Sarcomas Frequently Express Epidermal Growth Factor Receptor (EGFR, HER-1)

Endometrial stromal sarcomas are rare malignant mesenchymal uterine tumors. The expressions of different epidermal growth factor receptors such as EGFR (HER-1), HER-2, HER-3, and HER-4 have not yet been examined in these tumors. Twenty-three cases of endometrial sarcomas consisting of 20 low-grade endometrial stromal sarcomas and 3 undifferentiated endometrial sarcomas were examined immunohistochemically for EGFR (HER-1), HER-2, HER-3, and HER-4. EGFR (HER-1) was positive in 17 of 23 (74%) cases. While the three undifferentiated endometrial sarcomas were positive for EGFR, 14 of 20 (70%) low-grade endometrial stromal sarcomas showed positive reactions for EGFR. All examined cases were negative for HER-2, HER-3, and HER-4. This study is the first to show common expression of EGFR (HER-1) in endometrial stromal sarcomas. This finding may provide the basis for a new therapeutic strategy using monoclonal antibodies against EGFR (such as cetuximab) or small molecule inhibitors of EGFR (such as gefitinib) in patients with endometrial sarcomas.

[The morphologic features of endometrial stromal sarcoma and its metastases]

OBJECTIVE

To study the morphologic feature, immunohistochemistry phenotype of ESS and its metastases, with emphasis on the histogenesis, tumor differentiation and diagnostic criteria.

METHODS

The pathologic features of 15 cases and 4 metastases were studied. The immunohistochemical study was performed on selected sections by a panel of antibodies including CD10, smooth muscle actin, estrogen and progesterone receptors, keratin (AE1/3) and alpha-inhibin.

RESULTS

Patients were 22 to 75 years of age (mean 45). The endometrial stromal component predomominated in 7 cases. Three cases showed a picture of smooth muscle differentiation. Endometrial stromal sarcoma with fibromyxoid features were present in 2 cases. There were 3 sarcomas of poorly differentiated. The morphology features of the metastatic foci in 3 of the 4 metastasis cases were not similar to that of the primary counterpart in uteri. Among 14 ESS and 4 metastases, 15 of 18, 5 of 18, 7 of 18, and 10 of 18 were positive for CD10, SMA, ER and PR, respectively. AE1/3 and alpha-inhibin were only positive in the adenomatous area of ESS. Strong expression of SMA was obtained in all 10 cellular leiomyomas, and CD10 was only weakly expressed in 1 case (P < 0.05).

CONCLUSIONS

ESS are morphologically heterogeneous with multipotential differentiation. The histologic features of the metastases may not be similar to those of the primary. CD10 and SMA are diagnostically useful markers for ESS.

Low-grade endometrial stromal sarcoma presenting as vaginal nodule

Endometrial stromal sarcoma is a rare neoplasm of the uterus. Extrauterine locations of this neoplasm, excluding metastases or local extension, are even more unusual and are usually associated with the presence of endometriosis. The authors report a case of endometrial stromal sarcoma presenting as a vaginal wall nodule, without any sign of primary uterine tumor after extensive evaluation or presence of endometriosis. The morphology, immunohistochemical profile, differential diagnoses, and pathogenesis are discussed, as well as a review of the literature on this issue.

Distinction of endometrial stromal sarcomas from 'hemangiopericytomatous' tumors using a panel of immunohistochemical stains

Endometrial stromal sarcomas are low-grade malignant tumors that may pose a diagnostic challenge, especially when they are present in an extrauterine site. Owing to the presence of an arborizing vasculature and cells with an undifferentiated appearance, endometrial stromal sarcomas can be confused with several soft-tissue neoplasms. We studied 17 endometrial stromal sarcomas, eight hemangiopericytomas, 14 solitary fibrous tumors, and 16 synovial sarcomas immunohistochemically, detecting the following antigens: CD10, estrogen receptor, progesterone receptor, bcl-2, CD34, smooth muscle antigen, epithelial membrane antigen and cytokeratin (AE1/AE3). Most endometrial stromal sarcomas stained positively for CD10 (16/17), estrogen receptor (17/17), progesterone receptor (15/17), and bcl-2 (17/17). Staining with antismooth muscle antigen was seen in 11 of 17 cases of endometrial stromal sarcoma, with more intense staining seen in areas showing smooth muscle differentiation. Staining with AE1/3 was seen in four of 17 endometrial stromal sarcomas, with two of the positive cases containing epithelioid cells. None of the endometrial stromal sarcomas expressed epithelial membrane antigen or CD34. More than half of the hemangiopericytomas (4/8) and solitary fibrous tumors (9/14) cases demonstrated CD10 expression either focally or in a patchy cytoplasmic and membranous pattern. Hemangiopericytomas, solitary fibrous tumors, and synovial sarcomas did not express estrogen receptor. Four of eight hemangiopericytomas and seven of 14 solitary fibrous tumors also showed patchy progesterone receptor expression. CD34 expression was identified in six of eight hemangiopericytomas and 13 of 14 solitary fibrous tumors, but we did not find expression of CD34 in synovial sarcoma. Differences between endometrial stromal sarcoma and other soft-tissue tumors were detected for all of the immunohistochemical markers (P<0.05), except anti-bcl-2 and AE1/3. Antibodies against CD10 mark a substantial number of hemangiopericytomas and solitary fibrous tumors (albeit not diffusely) and should always be combined with antiestrogen receptor and CD34 when the differential diagnosis includes endometrial stromal sarcoma. Unlike estrogen receptor antibodies, progesterone receptor antibodies show at least focal nuclear staining in most hemangiopericytomas, solitary fibrous tumors and rare synovial sarcomas, and are not useful for this differential diagnosis. All endometrial stromal sarcomas expressed bcl-2, mostly in a diffuse pattern, but this did not distinguish between endometrial stromal sarcoma and mimics. We therefore recommend the use of a small antibody panel comprising anti-CD10, anti-estrogen receptor, and anti-CD34 to distinguish endometrial stromal sarcomas from tumors with a predominant hemangiopericytomatous growth pattern.

ERBB-2 gene overexpression and amplification in uterine sarcomas

BACKGROUND

The aim of this study was to determine ERBB-2 (HER-2/neu) gene alterations in different subtypes of uterine sarcomas.

METHODS

After central review, representative biopsies were immunohistochemically stained and semiquantitatively scored as negative, weakly (1+), moderately (2+), or strongly (3+) positive. Subsequently, fluorescence in situ hybridization (FISH) was performed on cases with 2+ and 3+ expression.

RESULTS

Seventy tumors (52 primaries and 18 recurrent) were evaluated. All 10 adenosarcomas, 21 endometrial stromal sarcomas, and 10 leiomyosarcomas were negative both in the primary and recurrent setting. Twenty-two primary carcinosarcomas were scored. The epithelial component was negative/1+ in 16 (73%), 2+/3+ in five (22.5%) tumors, and could not be evaluated in one case (4.5%), whereas the sarcoma component stained negative/1+ in 21 cases (95.5%) and 3+ (4.5%) in one case. In two recurrent carcinosarcomas, the epithelial component stained 3+ in both cases, whereas the sarcoma component scored negative and 1+. Amplification of the ERBB-2 gene as determined by FISH was observed in 3/7 (43%) carcinosarcomas with 2+ or 3+ overexpression, resulting in an overall 3/22 (14%) amplification rate. One out of four undifferentiated uterine sarcomas stained 2+. ERBB-2 immunopositivity (3+) and ERBB-2 amplification by FISH were confirmed in the recurrent tumor, resulting in a gene amplification rate of 1/4 in undifferentiated uterine sarcomas.

CONCLUSION

The current results suggest absence of ERBB-2 overexpression in uterine leiomyosarcoma, uterine adenosarcoma, and endometrial stromal sarcoma, whereas the ERBB-2 gene might have a biologic role in uterine carcinosarcoma and undifferentiated uterine sarcomas.

Treatment and recurrence patterns in endometrial stromal sarcomas and the relation to c-kit expression

INTRODUCTION

Endometrial stromal sarcomas (ESS) are a rare gynecologic malignancy. The optimal management of this cancer remains unclear, although previous reports have failed to demonstrate a clear benefit to adjuvant chemotherapy or radiation. With the successful application of directed biological therapy in other sarcomas, a review of the behavior and biology of this disease is warranted.

OBJECTIVES

To review outcomes and patterns of failure in patients with endometrial stromal sarcoma diagnosed over 31 years at our institution and the relationship to protooncogene c-kit expression.

MATERIALS AND METHODS

Hospital records and pathology were reviewed for 28 patients with endometrial stromal sarcomas [19 low-grade (LGESS) and 9 high-grade (HGESS)] treated between 1972 and 2003. Archival tissue samples from 16 patients were available and stained with CD 117 (c-kit) antibody (1:25 dilution). Staining intensity was graded 1+ to 3+ and distribution of the cellular staining as focal (10-30% of the cells), intermediate (30-60% of the cells), or diffuse (>60% of the cells). Positive tumors had more than 10% of cells comprising the neoplasm display immunoreactivity. RESULTS.: We found a significant difference in 5-year overall survival between LGESS and HGESS (P = 0.001). There was no significant difference in overall survival for patients with local versus advanced disease (P = 0.53) or in overall survival for those who underwent lymphadenectomy and those who did not (P = 0.92). 50% of patients received postoperative radiation with no difference in disease-free or overall survival (P = 0.68 and P = 0.53). Ten patients relapsed (36%, four HGESS and six LGESS). Seven of sixteen (43.8%) tumor samples expressed detectable c-kit. Five of seven (71%) were HGESS, and the other two (22%) were LGESS tumors. The median survival of patients with c-kit-positive versus c-kit-negative tumors was 12 and 47 months, respectively.

CONCLUSIONS

This study confirms the superior overall prognosis of LGESS relative to HGESS, despite the similar rates of relapse. Although hard to assess, due to population heterogeneity and small numbers, adjuvant chemotherapy and radiation appear to be of limited benefit. Expression of c-kit was common, especially in high-grade lesions and may represent a potential therapeutic target.

Ovarian neoplasms composed of small round cells: a review

Ovarian neoplasms composed predominantly or exclusively of small round cells with scant cytoplasm are relatively rare. However, there is a wide differential, and pathologists often struggle to make a correct diagnosis because of overlapping histologic features. Perhaps the best known of these neoplasms is ovarian small cell carcinoma of hypercalcemic type (OSCCHT), a tumor of unknown histogenesis. This may be confused with a wide range of neoplasms ranging from sex cord-stromal tumors (some of which may exhibit a small cell phenotype) to neoplasms in the family of small round blue cell tumors to various undifferentiated malignancies. A neuroendocrine small cell carcinoma, so-called small cell carcinoma of pulmonary type, may also arise within the ovary, and this may be a component of a typical ovarian surface epithelial-stromal tumor. In addition to the well-known family of small round blue cell tumors of childhood, other small cell neoplasms that may arise within the ovary or involve the ovary include intra-abdominal desmoplastic small round cell tumor, metastatic small cell carcinoma, peripheral and central primitive neuroectodermal tumor, and endometrial stromal sarcoma. Malignant melanoma, undifferentiated carcinoma, and various germ cell tumors, especially dysgerminoma and immature teratoma, also on occasion enter into the differential diagnosis of an ovarian small cell neoplasm. In this review, the morphologic features of some of these neoplasms are described, as is the value of immunohistochemistry and other ancillary techniques in establishing a diagnosis.

Recurrence of prolactin-producing endometrial stromal sarcoma with sex-cord stromal component treated with progestin and aromatase inhibitor

INTRODUCTION

Endometrial stromal tumors with sex-cord-like elements are relatively rare. We report a case of this neoplasm with prolactin as a tumor marker for recurrent disease. We also report response of recurrent disease to progesterone and aromatase inhibitor.

CASE REPORT

A 48-year-old woman was diagnosed with Stage I endometrial stroma sarcoma with sex-cord component at the time of hysterectomy for presumed fibroid uterus. One and a half years later, she presented with recurrent disease in the abdomen associated with breast tenderness, galactorrhea, and an elevated prolactin level. She received three cycles of BEP (Bleomycin, Etoposide, Cisplatin) with partial response and followed by an optimal debulking procedure. Two out of a six additional planned cycles of BEP were administered with complete tumor response and normalized prolactin level. Second recurrence, 9 months later, again presented with galactorrhea and rising prolactin. Disease was progressive through three cycles of Docetaxel and Gemcitabine therapy, but had an objective response to treatment with anastrozole and megestrol acetate. Prolactin level normalized. Two years later there is stable disease and the patient remains symptom-free.

DISCUSSION

Endometrial stromal sarcoma with sex-cord stromal component may be hormonally functional. Similarly to pure endometrial stromal sarcomas, they may respond to hormonal treatment, and further study is warranted.

Tumour Lines from a Spontaneous Rat Endometrial Stromal Sarcoma, Showing Dendritic Cell-like and Myofibroblastic Cell-like Phenotypes

A transplantable tumour (RY) and cell lines (RY-PB and clone RY-B-E3 isolated from RY-PB) were established from a naturally occurring endometrial stromal sarcoma (ESS) found in a 24-month-old female F344 rat. The primary tumour and RY tumours, which had been serially passaged in syngeneic female rats up to the 10th generation, consisted of spindle or round cells arranged in ill-defined bundles or sheets. Neoplastic cells of the primary and RY tumours, as well as cultured cells of RY-PB and RY-B-E3, showed positive reactions to vimentin, ED1/ED2 (both for rat macrophages/histiocytes), OX6 (for dendritic cells expressing rat MHC class II antigens), and lysosomal enzymes such as acid phosphatase and non-specific esterase, in varying degrees. Ultrastructurally, neoplastic cells characteristically had tubulovesicular system-like structures and variously developed lysosomes in the cytoplasm. Neoplastic cells also exhibited immunoexpression to an alpha-smooth muscle actin (alpha-SMA). The addition of transforming growth factor (TGF)-beta1 to RY-PB and RY-B-E3 cultures increased the number of alpha-SMA-positive cells, whilst the positive cell number was decreased by anti-TGF-beta antibody. The RT-PCR method revealed the expression of TGF-beta1 mRNA in the cultured cells. The present study showed that rat ESS-derived cells exhibited dendritic cell-like and myofibroblastic cell-like phenotypes. The histogenesis of ESSs in human beings and rats remains poorly understood, and these tumour lines may therefore become useful tools for further research.

Expression of androgen receptors in benign and malignant endometrial stromal neoplasms

Several studies have shown that endometrial stromal neoplasms express estrogen and progesterone receptors (ER, PR). To our knowledge, the presence or absence of androgen receptors (AR) in these rare uterine neoplasms has not been investigated. Tumors ( n=20)-3 endometrial stromal nodules, 14 low-grade endometrial stromal sarcomas (ESS, low grade), and 3 high-grade endometrial sarcomas (undifferentiated endometrial sarcoma, UES)-were studied. Immunohistochemical analyses for ER, PR, and AR were performed on formalin-fixed, paraffin-embedded archival material. Positive immunoreactions for ER and PR were observed in 14 (70%) and 17 (85%) cases, respectively. Furthermore, 9 cases (45%) were positive for AR. Among 17 ESS and UES cases, 7 (41%) revealed positivity for AR. Two of three benign stromal nodules were also positive for AR. Moreover, one of the three high-grade sarcomas (undifferentiated endometrial sarcoma) was negative for both ER and PR, but showed positive reaction for AR. In summary, ARs are expressed in 45% of endometrial stromal neoplasms. In addition to determination of ER and PR, the results of immunohistochemical examination of AR in these rare uterine tumors may have some impact on the postoperative management of the patients.

Expression of Progesterone Receptor A and B Isoforms in Low-grade Endometrial Stromal Sarcoma

The progesterone receptor (PR) exists as two isoforms, PRA and PRB. In vitro studies have shown that these proteins are functionally distinct, suggesting that their relative expression can influence progesterone response. Low-grade endometrial stromal sarcoma (LGESS) is an uncommon tumor that usually expresses PR. In normal endometrial stroma, both PR isoforms are present with PRA predominant throughout the menstrual cycle. The relative expression of PRA and PRB in LGESS has not been previously reported. All nine cases of primary LGESS (seven uterine, two extrauterine) expressed PRB. Eight tumors also contained PRA and it was the predominant isoform in seven cases. These tumors had similar histopathologic appearances, whereas a case with approximately equal PR isoform expression showed features of sex cord or smooth muscle differentiation. An extrauterine tumor expressing only PRB had myxoid stroma. Recurrent tumor in two cases, which expressed predominantly PRA in the primary, contained reduced levels of PR consisting predominantly or entirely of PRB after prolonged interval progestin therapy. Most primary LGESSs showed PR isoform expression similar to normal endometrial stroma, consistent with the highly differentiated phenotype of this tumor. Variant differentiation or disease recurrence was accompanied by an altered PR isoform profile that could impact on hormone response.

Immunohistochemical markers in differential diagnosis of endometrial stromal sarcoma and cellular leiomyoma

OBJECTIVE

Distinction of endometrial stromal sarcoma (ESS) from benign smooth muscle proliferations like cellular leiomyoma (CL) is sometimes problematic. The purpose of this study was to evaluate the potential utility of a panel of antibodies in the differential diagnosis of ESS and CL.

METHODS

Using a standard streptavidin-biotin method, the expression of desmin, alpha smooth muscle actin (SMA), calponin h1, h-caldesmon, estrogen receptor (ER), progesterone receptor (PR), CD10, CD44v3, proliferating cell nuclear antigen (PCNA), and mast cells (MCs) were evaluated in 26 cases of ESS (21 low grade, 5 high grade), 25 CL (17 common CL, 8 highly CL), 25 myometria, and 25 endometria.

RESULTS

Among ESS, 20 of 26, 17 of 26, 9 of 26, 12 of 26, 14 of 26, and 22 of 26 were positive for expression of desmin, SMA, calponin h1, ER, PR, and CD10, respectively, while only 2 of 26 were positive for CD44v3 and all were entirely negative for h-caldesmon. Of CL, all were positive for SMA, calponin h1, PR, and CD44v3; 24 of 25, 24 of 25, and 19 of 25 were positive for desmin, h-caldesmon, and ER, respectively, whereas 1 of 25 focally marked with antibodies to CD10. There was no significant difference of PCNA expression between ESS and CL, although the ESS cases tended to have higher values. The MC counts were significantly higher in the CL group than in the ESS group (P < 0.01). When using the cut-off value of seven MCs per HPF to distinguish ESSs from CLs, the sensitivity and specificity of this cut-off value were 92.9% and 100%, respectively.

CONCLUSIONS

A panel of h-caldesmon, CD10, and CD44v3 should be used and will distinguish ESS from CL in most cases. In addition, counting the number of MCs might be useful as part of a multivariate approach to the differential diagnosis of them. But the biological function of MC and CD44v3 in these tumors is worthy of further investigation.

Use of Oxytocin Receptor Expression in Distinguishing Between Uterine Smooth Muscle Tumors and Endometrial Stromal Sarcoma

The present study aimed to investigate oxytocin receptor (OTR) expression in the normal uterus, and particularly in uterine smooth muscle tumors and endometrial stromal sarcomas (ESSs) because these tumors can be difficult to distinguish. The expressions of OTR, CD10, h-caldesmon, calponin, smooth muscle actin, and desmin were analyzed in 10 conventional leiomyomas (LMs), 10 highly cellular leiomyomas (HCLs), eight leiomyosarcomas (LMSs), and nine ESSs. In five normal uteri and five cases of adenomyosis, OTR was strongly expressed in the myometrium and showed expression pronounced in the surface epithelium during the late proliferative phase and at the time of ovulation, whereas the endometrial stromal cells were negative. All LMs and HCLs were strongly positive for OTR. Five cases of LMS showed moderate to strong OTR expression in 100% of the tumor cells, whereas three cases were weakly positive in 10-20% of the tumor cells. Every ESS was negative for OTR, except in regions of smooth muscle differentiation. All ESSs were positive for CD10, as were one LM, six HCLs, and five LMSs. The ESSs were negative for h-caldesmon and showed desmin positivity mainly in regions of smooth muscle metaplasia. h-Caldesmon, calponin, smooth muscle actin, and desmin were expressed in all LMs, HCLs, and LMSs except for one leiomyosarcoma with epithelioid features, which was negative for h-caldesmon and calponin. Our study indicates that the evaluation of OTR expression is useful in the distinction of uterine smooth muscle tumors from ESSs, and that the OTR is expressed in normal and neoplastic uterine smooth muscle cells.

Long-term survival of patients given hormonal therapy for metastatic endometrial stromal sarcoma

Endometrial stromal sarcoma (ESS) is a rare neoplasm, mainly observed in premenopausal women. We describe two women 44 and 34 years old at the time ESS diagnosis, who developed lung metastases 3 and 6 years, respectively, after initial treatment: hysterectomy without (case 1) or with oophorectomy (case 2), followed by hormone replacement therapy (HRT) for the latter. Their estrogen (ER) and progesterone receptors (PR) were analyzed biochemically in metastatic lung tissue, yielding respective concentrations of ER 242 and 184, and PR 910 and 100 fmol/mg of cytosol protein. Both patients started treatment with the aromatase inhibitor aminoglutethimide (500 mg qid) after surgery for the first patient and after stopping HRT for the second. Under aromatase-inhibitor therapy, both patients achieved a complete response, patient 1 remains disease- free with 14+ years of follow-up, and patient 2 with 7+ years. Our data suggest that an aromatase inhibitor may be an effective treatment for ESS. Furthermore, routine ER and PR analyses could be useful to predict the response to hormonal therapy in ESS.

Uterine sarcomas express KIT protein but lack mutation(s) in exon 11 or 17 of c-KIT

OBJECTIVE

Several tumors express the protein product of the protooncogene c-KIT. Some of these respond to imatinib mesylate, a tyrosine kinase inhibitor. The tumors that respond frequently have mutation(s) in exon 11 of c-KIT that encodes for the regulatory juxtamembrane helix. Some tumors that express KIT protein have mutation(s) in exon 17 of c-KIT; however, these do not respond to imatinib mesylate. This investigation was performed to determine the expression of KIT protein and mutational status of exons 11 and 17 of c-KIT in uterine sarcomas.

METHODS

Twenty-five uterine sarcomas treated from 1990 to 2002 were evaluated. These included 14 malignant mullerian mixed tumors (MMMT), 7 leiomyosarcomas (LMS), 2 endometrial stromal sarcomas (ESS), and 2 high-grade heterologous sarcomas (HGHS). Formalin-fixed, paraffin-embedded tissue sections were immunostained with anti-KIT antibody (Santa Cruz Biotechnology, Santa Cruz, CA) with a semiquantitative assessment. Normal myometrium when present in the section was used as an internal negative control. Areas of tumor were microdissected followed by DNA extraction, polymerase chain reaction (PCR) amplification of exons 11 and 17, single-strand conformational polymorphism (SSCP), and DNA sequencing to detect the presence of mutation(s).

RESULTS

All 25 tumors expressed KIT protein at varying levels as assessed by immunohistochemistry. The staining was diffuse and of moderate to strong intensity in 22 tumors. In three tumors (one of each type except MMMT) the staining intensity was weak. In MMMT the epithelial and sarcomatous foci stained similarly. No mutation(s) in exons 11 or 17 of c-KIT were identified in 24/25 tumors. One LMS had deletion of both exons 11 and 17.

CONCLUSIONS

Although uterine sarcomas express KIT protein, they lack KIT-activating mutation(s) in exon 11 or 17 of c-KIT. Therefore, these tumors are unlikely to respond to imatinib mesylate.

Myxoid endometrial stromal sarcoma of the uterus

A rare case of a myxoid type of endometrial stromal sarcoma of the uterus in a 41-year-old woman is reported. A tumor was found in the myometrium and was well circumscribed, measuring 9 x 7 x 7 cm in size. The tumor was mainly composed of a hypocellular area with tumor cells separated by prominent myxoid stroma. The tumor cells were spindle-shaped and resembled endometrial stromal cells. Numerous small thin-walled vessels were seen throughout the tumor. Immunohistochemically, the tumor cells were diffusely stained for estrogen and progesterone receptors and CD10, and focally and weakly for HHF35, alpha-smooth muscle actin and desmin, but not stained for h-caldesmon. These results indicated that the tumor originated from endometrial stromal cells. The tumor had an increased mitotic activity (MIB-1 labeling index: 1-10%), and focally showed nuclear pleomorphism. Thus, this tumor had a malignant potential and was diagnosed as a myxoid type of low-grade endometrial stromal sarcoma. The patient is currently well with no evidence of local recurrence or metastasis 21 months after the operation. This case indicates a wide morphological spectrum of endometrial stromal tumor. A myxoid endometrial stromal sarcoma should be considered in the different diagnosis of the intramural myxoid tumors in the uterus.

The proto-oncogene c-kit is expressed in leiomyosarcomas of the uterus

OBJECTIVE

The proto-oncogene c-kit encodes for a 145-kDa transmembrane tyrosine kinase receptor. Interaction with its ligand, stem cell factor, is essential in the development of hematopoietic stem cells, mast cells, gametocytes, melanocytes, and interstitial cells of Cajal. C-kit expression has been identified in a number of different neoplasms that includes mastocytosis/mast cell leukemia, acute myeloblastic leukemia, seminoma/dysgerminoma, and gastrointestinal stromal tumors. This study examines c-kit expression in uterine endometrial stromal sarcomas, leiomyomas, and leiomyosarcomas using immunohistochemistry.

METHODS

Archival tissue from 38 patients with the uterine mesenchymal tumors (16 leiomyosarcomas, 8 leiomyomas, 11 low-grade endometrial stromal sarcomas, and 3 high-grade endometrial stromal sarcomas) was stained with polyclonal antibody for c-kit. Modified avidin biotin (ABC) immunoperoxidase method was employed for antibody detection. Individual tumors were considered positive if more than 10% of the cells comprising the neoplasm displayed immunoreactive staining. Staining intensity was graded 1+ to 3+ and distribution graded as focal (10-30% of the cells), intermediate (30-60% of the cells), or diffuse (>60% of the cells).

RESULTS

C-kit was positive in 12 (75%) of the 16 leiomyosarcomas. The staining was 3+ and diffuse in the majority of the positive tumors. C-kit expression was not detected in any of the 8 leiomyomas. Two of the 3 high-grade endometrial stromal sarcomas displayed c-kit positivity. Staining was diffuse and 3+ in both of these tumors. Expression of c-kit was observed in only 3 of the 11 low-grade endometrial stromal sarcomas.

CONCLUSIONS

C-kit is expressed in uterine leiomyosarcomas and endometrial stromal sarcomas. Adjunctive diagnostic studies using c-kit may be useful in distinguishing leiomyosarcomas from benign leiomyomas in uterine tumors that offer uncharacteristic features. Furthermore, studies should investigate the prospect of treating these malignant tumors with tyrosine kinase inhibitors.

MIB1 as a possible predictor of recurrence in low-grade endometrial stromal sarcoma of the uterus

OBJECTIVE

Immunohistochemical analysis of MIB1, p53, estrogen, and progesterone receptors can provide prognostic information in endometrial adenocarcinoma. Since predictors of recurrence for low-grade endometrial stromal sarcoma (LESS) are still unknown, a battery of immunostains was performed to find markers, which might be useful to predict prognosis.

METHODS

Eleven patients with an average age of 43.8 years (range 27-76) were identified with stage I LESS. Immunostains, including MIB1, p53, ER, and PR, were evaluated by two pathologists, independently.

RESULTS

All tumors were positive for ER and PR; 1/11 was positive for p53; MIB1 ranged from 0 to 20% positive tumor nuclei. Mitotic counts ranged from 0 to 7/10 hpf. Two patients developed recurrences. One had a pelvic recurrence 7 years after diagnosis. This tumor had a mitotic count of 1/10 hpf, MIB1 expression in 10% of nuclei, and focal p53 expression. A second patient developed pulmonary metastases 10.8 years after diagnosis; the tumor showed a mitotic count of 7/10 hpf and MIB1 expression in 20% of nuclei, but was negative for p53. There was a significant difference in MIB1 reactivity scores between patients who did or did not develop recurrence (P = 0.0303). A marginally significant association was detected between MIB1 (P = 0.0896) or p53 (P = 0.0833) positivity and length of recurrence-free survival.

CONCLUSION

Although MIB1 and p53 appear to be useful prognostic markers, a larger study would be necessary to confirm their validity.

Low-grade endometrial stromal sarcoma: hormonal aspects

OBJECTIVE

The goal of this work was to determine whether exposure to estrogen following treatment of low-grade endometrial stromal sarcomas affects clinical outcome.

METHODS

Twenty-two patients with low-grade endometrial stromal sarcomas were reviewed to determine whether they were exposed to exogenous or endogenous estrogen and/or progestins following their diagnosis and whether exposure to these hormones might have influenced their prognosis. Estrogen receptor (ER) alpha and beta and progestin receptor (PR) status were analyzed from paraffin-embedded tissue by immunohistochemistry and ER mRNA was measured in fresh tissue by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Ten of the twenty-two patients with low-grade endometrial stromal sarcomas developed recurrent disease. Four of five patients (80%) who received estrogen replacement therapy (ERT) recurred. Four of eight patients (50%) with retained ovaries recurred. Eight of the ten specimens available for analysis were positive for ERalpha, none were positive for ERbeta, and 9 of 10 were positive for PR. Four of thirteen patients who received progestins as adjuvant therapy recurred, compared with 6 of 9 patients who did not receive progestins (31% vs 67%). Eight recurrences were treated with progestin therapy and 7 (88%) of them had either stable disease (3/8, 38%) or complete response (4/8, 50%).

CONCLUSIONS

Our results suggest that ERT may be detrimental in patients with low-grade endometrial stromal sarcoma. Retention of normally functioning ovaries, on the other hand, may not significantly affect the recurrence rate following hysterectomy alone in Stage I patients. The lack of ERbeta expression in endometrial stromal sarcomas compared with normal endometrial stromal cells suggests that loss of ERbeta may be a marker for malignancy. Progestin therapy should be routinely considered for adjuvant therapy and for the treatment of recurrent endometrial stromal sarcomas.

Lack of expression of c-kit protein (CD117) in mesenchymal tumors of the uterus and ovary

c-kit is a proto-oncogene that codes for a transmembrane tyrosine kinase receptor (CD117). The gene product KIT is constitutively overexpressed in mastocytosis and gastrointestinal stromal tumors. Recently the use of the tyrosine kinase inhibitors, such as STI-571, has resulted in the successful treatment of bcr-abl-positive leukemias and gastrointestinal stromal tumors. In gastrointestinal stromal tumors, immunostaining for c-kit is diffusely positive. Because the expression of c-kit in mesenchymal tumors of the uterus and ovary has not been previously studied, we evaluated its expression in 38 of these tumors by immunohistochemistry. The number of positive labeled/total tumors were as follows: 0/8 malignant mullerian mixed tumors, 4/7 ovarian fibrosarcomas, 0/1 clear-cell ovarian sarcoma, 0/4 uterine leiomyosarcomas, 1/10 low-grade endometrial stromal sarcomas, 0/2 high-grade endometrial stromal sarcomas, and 3/6 endometrial stromal nodules. In all positive cases, no more than 5% of the cells were labeled. In conclusion, unlike gastrointestinal stromal tumors, mesenchymal tumors of the uterus and ovary rarely express c-kit. Therefore, it is unlikely that patients with these tumors will benefit from treatment with the currently available tyrosine kinase inhibitors.

Endometrial stromal sarcoma of the retroperitoneum

Endometrial stromal sarcoma (ESS) is an uncommon neoplasm whose occurrence outside the uterus is extremely rare in the absence of metastasis or extension of a primary uterine neoplasm. When ESS occurs in such locations it is often associated with the uterine adnexa or serosal surface of various organs. Although rare, ESS is usually considered in the differential diagnosis of spindle cell neoplasms in the female patient. We report a case of ESS arising in the retroperitoneum and discuss the morphologic and immunohistochemical features in the context of the differential diagnosis of a retroperitoneal low-grade spindle cell neoplasm occurring in the female patient.

Expression of CD10 in malignant müllerian mixed tumors and adenosarcomas: an immunohistochemical study

CD10 has been demonstrated to be positive in endometrial stromal sarcoma (ESS) and thus is useful in establishing the diagnosis, but its expression in malignant müllerian mixed tumor (MMMT) and müllerian adenosarcoma remains to be clarified. In this study, 12 cases of MMMT (9 uterine, 2 tubal, and 1 metastatic), 6 cases of müllerian adenosarcoma (three corporeal, two cervical, and one tubal), and 7 cases of primary uterine sarcomas had their tissues examined immunohistochemically for expression of CD10, desmin, myoglobin, alpha-smooth muscle actin (SMA), and cytokeratin. Of the primary uterine sarcomas, two were primary rhabdomyosarcomas (one cervical and one corporeal), two were ESSs, two were high-grade leiomyosarcomas, and one was a high-grade endometrial sarcoma. Sarcomatous components in all cases of MMMT and müllerian adenosarcoma, as well as all uterine sarcomas, were positive for CD10, showing moderate to marked staining intensity with varying distribution except in one MMMT, which showed weak and very focal staining. In four MMMTs, three adenosarcomas, and one rhabdomyosarcoma, myoglobin- and/or desmin-positive rhabdomyoblastic cells were positive for CD10. The immunoreactivity for CD10 showed the same distribution for alpha-SMA and myoglobin in three and two MMMTs, respectively. In five cases of MMMT, carcinomatous components were focally positive for CD10, and in two cases small populations of round or short spindle cells in sarcomatous components were positive for CD10, alpha-SMA, and cytokeratin (CAM5.2). These results indicate that CD10 expression is not restricted to ESS but can be positive in MMMT and müllerian adenosarcoma as well as in a variety of uterine tumors including high-grade leiomyosarcoma and rhabdomyosarcoma. CD10 expression might be one of the characteristics of müllerian system-derived neoplastic mesenchymal cells.

CD10 is a marker for normal and neoplastic endometrial stromal cells

Using the immunohistochemical technique, we investigated the expression of CD10 in normal female genital tissues, chorionic villi and decidua of early gestation, endometriotic lesions, and uterine mesenchymal tumors. The cytoplasm of normal endometrial stromal cells was consistently positive for CD10. During early gestation, decidualized endometrial stromal cells were negative or only focally positive for CD10, whereas nondecidualized stromal cells were diffusely positive. Syncytiotrophoblast was positive for CD10 on the apical surface, whereas chorionic mesenchymal cells were diffusely positive within the cytoplasm. Cytotrophoblast and intermediate trophoblast were negative for CD10. Groups of stromal cells surrounding cervical glands were often positive for CD10. Myometrium, endometrial and cervical glands, cervical squamous epithelia, and tubal epithelia and stroma exhibited no reactivity for CD10. In endometriosis and adenomyosis, ectopic endometrial stromal cells were usually positive for CD10. Endometrial stromal tumors, including undifferentiated uterine sarcomas, mostly showed diffuse immunoreactivity for CD10. Leiomyomas and leiomyosarcomas were negative or focally (< 5% of cells staining) positive (8/12 leiomyomas and 4/8 leiomyosarcomas) for CD10, except for 1 myxoid leiomyosarcoma that showed CD10 staining in the myxoid areas. These data suggest that diffuse CD10 staining is characteristic of normal and neoplastic endometrial stromal cells, unless they are decidualized.