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

Highly malignant endometrial stromal sarcoma in a cat

An 11-year-old female Persian cat underwent ovariohysterectomy due to dilation of the uterine cavity with irregular thickening of the wall. Macroscopically, the middle and distal regions of the left uterine horn were swollen and the uterine wall was irregularly thickened due to the development of multiple coalescent, variably sized nodules. Microscopically, the nodules had originated in the endometrium and were composed of round to polygonal neoplastic cells arranged in dense sheets or ill-defined fascicles. The neoplastic cells had locally invaded the myometrium and reached the subserosa, with lymphovascular invasion. Immunohistochemically, the neoplastic cell population was partially positive for CD10, an established marker of endometrial stromal sarcoma (ESS) in humans, with focal and diffuse nuclear immunopositivity for oestrogen and progesterone receptors and immunonegativity for desmin and α-smooth muscle actin. Based on these findings, the uterine tumour was diagnosed as ESS and was considered to correspond morphologically to high-grade ESS in humans.

Cutaneous Syncytial Myoepithelioma with Positive CD34 Immunohistochemical Staining: An Unusual Tumor and a Challenging Diagnosis

Cutaneous syncytial myoepithelioma (CSM) is a rare type of cutaneous neoplasm that typically presents as a solitary and well-circumscribed nodule on the skin. It predominantly occurs on the upper and lower extremities of adult patients. Immunohistochemically, CSM is characterized by the co-expression of smooth muscle and epithelial markers. Fluorescence in situ hybridization (FISH) targeting the EWSR1 gene rearrangement is an important diagnostic tool for CSM. In our case report, we found the focal positivity for CD34, which has never been previously observed; this was mostly confined to a central area of the neoplasm.

Angiomyofibroblastoma and Potential Mimicking Soft Tissue Tumors That May Occasionally Present in the Retroperitoneum: An Approach to the Differential Diagnosis With Report of an Unusual Index Case Abutting the Kidney

The retroperitoneal soft tissues, extending from the pelvic floor to the level of the diaphragm, are the source of a variety of mesenchymal neoplasms with overlapping features and distinct clinical behaviors, making their distinction of crucial importance. Herein, we report a rare retroperitoneal angiomyofibroblastoma (AMFB) that presented as a right abdominal mass in a 25-year-old woman and that clinically simulated a primary renal carcinoma. The patient underwent complete surgical resection showing a well-circumscribed tumor adjacent to but separate from the right kidney. It was comprised of irregular, often anastomosing islands and cords of plump to spindled cells in a collagenous stroma with numerous thin-walled vessels. The tumor cells clustered around the vessels and admixed with moderate numbers of adipocytes. There was neither significant nuclear atypia nor mitotic activity. Immunohistochemically, the tumor cells showed strong reactivity for desmin, diffuse expression of estrogen and progesterone receptors, retained nuclear expression of retinoblastoma protein, and absent CD34 expression. The immunomorphological features were these of a "lipomatous variant" of AMFB of the retroperitoneum. The occurrence of AMFB in the retroperitoneum is unexpected since it mostly develops in the lower genital tract of young women, making its recognition in this rare location difficult. As a consequence, more common pelvic or retroperitoneal soft tissue neoplasms may represent the primary diagnostic considerations. We, therefore, review a variety of soft tissue tumors occurring in the pelvis/retroperitoneum that, to some degree, may mimic AMFB, and present key findings to assist in accurate diagnosis.

Solitary Fibrous Tumors of the Female Genital Tract: A Study of 27 Cases Emphasizing Nonvulvar Locations, Variant Histology, and Prognostic Factors

We report 27 solitary fibrous tumors of the female genital tract emphasizing nonvulvar locations, variant histology, and prognostic factors. The patients ranged from 25 to 78 years (most were over 40), and tumors occurred in the vulva (7), vagina (2), cervix (2), corpus (6), fallopian tube/paratubal soft tissue (5), and ovary (5). They ranged from 1.5 to 39 (mean=10.5) cm and were typically solid, but 4 were predominantly cystic. All had a haphazard arrangement of spindled to ovoid cells, with most demonstrating alternating cellular and hypocellular areas and prominent vessels, but 13 lacked hypocellular areas, and 7 had focal diffuse growth with inconspicuous vasculature. Other patterns included corded (8), fascicular (5), trabecular (1), and nested (1). Microcysts (6), myxoid background (8), hyalinization (8), lipomatous differentiation (2), and multinucleated cells (6) were also present, and 10 tumors had necrosis. Vasculature included thin-walled branching "staghorn" (27), thick-walled (7), and hyalinized vessels (5) or dilated anastomosing vascular channels (3). Nuclear atypia ranged from mild (19), moderate (7), to severe (1), and mitoses from 0 to 24/10 HPF (mean=4). STAT6 was positive in all 25 tumors tested. One tumor showed dedifferentiation; the remainder were classified as benign (19) or malignant (7) based on mitotic rate (univariate stratification model) and as low risk (14), intermediate risk (8), or high risk (4) based on the Demicco multivariate risk stratification score. Follow-up (median=23 mo) was available for 16 patients. Six tumors recurred (2 intermediate risk, 3 high risk, and the dedifferentiated tumor), 5 in the abdomen; the dedifferentiated tumor metastasized to the lung. Multivariate risk stratification was superior to univariate classification, as 5 "benign" tumors were reclassified as intermediate risk using the multivariate model; of these, 2 recurred, and 1 patient died of disease. Upper female genital tract tumors occurred in older patients, were larger, and more frequently classified as high risk compared with those of the lower tract. A trend toward increased cellularity was also seen in the upper tract tumors. Only size (P=0.04), necrosis (P=0.04), and Demicco score (P=0.01) independently correlated with recurrence. Female genital tract solitary fibrous tumors demonstrate a wide range of variant morphologies and occur in diverse sites in addition to the vulva. Tumors were often misdiagnosed as other neoplasms; thus, awareness of solitary fibrous tumors occurring at these sites is crucial in prompting staining for STAT6 to establish this diagnosis. The Demicco risk stratification system effectively predicts behavior.

Clinicopathological characteristics and treatment of patients with high-grade endometrial stromal sarcoma: A retrospective study of 40 cases

To investigate the clinicopathological characteristics of patients with high-grade endometrial stromal sarcoma (HG-ESS).The clinicopathological characteristics, treatments, and prognostic information of consecutive HG-ESS patients were collected from medical records and then evaluated.A total of 40 women were included in the analysis. The immunohistochemical profiles indicated that HG-ESS tumors tend to be locally or weakly positive for vimentin (100%) and CD10 (72.0%) but mostly negative for desmin (7.7%) and AE1/AE3 (9.1%). The progression-free survival intervals and the clinical benefit rates of patients receiving radiotherapy and/or chemotherapy were slightly longer and higher than those receiving simple observation (progression-free survival: 6 and 5 months vs 2 months; clinical benefit rate: 83.3% and 75.0% vs 28.6%). The 1-year disease-specific survival (DSS) rate was 62.7%. Tumor size, myometrial invasion, lymphovascular space invasion, cervical involvement, Federation International of Gynecology and Obstetrics (FIGO) stage, and residual disease all significantly affected the DSS rate (P < .001, =.002, <.001, =.004, <.001, and <.001, respectively). For patients with stage I disease, the 1-year DSS rate was as high as 91.7%, in contrast to 66.7%, 26.7%, and 0% for those with stage II, III, and IV disease, respectively.HG-ESS is associated with an adverse prognosis. FIGO stage could effectively predict the prognosis of patients with this lethal disease. Immunohistochemical markers, vimentin+/CD10+ (local or very weak), in combination with desmin-/AE1/AE3-, may be helpful for improving the diagnostic accuracy of this lethal condition. The therapeutic roles of adjuvant chemotherapy and radiotherapy warrant further investigation.

Extragenital endometrial stromal sarcoma of transverse mesocolon: A diagnostic conundrum

Endometrial stromal sarcoma (ESS) is a rare uterine neoplasm infrequently arising in extra-genital sites. Herein, we report an extremely rare case of primary extra-genital ESS of transverse mesocolon occurring in a 51-year-old female presenting with gradually increasing abdominal mass. The clinical diagnosis considered was a gastrointestinal stromal tumor. Intra-operatively, the mass was confined exclusively to the transverse mesocolon. Microscopy revealed a cellular tumor composed of oval to elongate neoplastic cells with hyperchromatic nuclei, inconspicuous nucleoli and were immunoreactive for CD10, progesterone receptor (PR), estrogen receptor (ER), and PAX8; negative for KIT, CD34, SMA, S100, synaptophysin, chromogranin, WT-1, and calretinin. A distinct arborizing network of arterioles along with foci of endometriosis was also seen. We present this case for its extreme rarity and the challenges entailed in its diagnosis.

A Case of Malignant Phyllodes Tumor of the Breast Metastasizing to the Ovary

Phyllodes tumors of the breast are uncommon, and 6.2% of phyllodes tumors behave in a malignant fashion. The metastatic spread of malignant phyllodes tumor is mainly hematogenous to lung and bone, and malignant phyllodes tumor metastasizing to the ovary is rare, with only 2 cases reported. We report the third case of metastatic malignant phyllodes tumor to the ovary with a focus on the differential diagnosis of ovarian cancer.

Update on Endometrial Stromal Tumours of the Uterus

Endometrial stromal tumours (ESTs) are rare, intriguing uterine mesenchymal neoplasms with variegated histopathological, immunohistochemical and molecular characteristics. Morphologically, ESTs resemble endometrial stromal cells in the proliferative phase of the menstrual cycle. In 1966 Norris and Taylor classified ESTs into benign and malignant categories according to the mitotic count. In the most recent classification by the WHO (2020), ESTs have been divided into four categories: Endometrial Stromal Nodules (ESNs), Low-Grade Endometrial Stromal Sarcomas (LG-ESSs), High-Grade Endometrial Stromal Sarcomas (HG-ESSs) and Undifferentiated Uterine Sarcomas (UUSs). ESNs are clinically benign. LG-ESSs are tumours of low malignant potential, often with indolent clinical behaviour, with some cases presented with a late recurrence after hysterectomy. HG-ESSs are tumours of high malignant potential with more aggressive clinical outcome. UUSs show high-grade morphological features with very aggressive clinical behavior. With the advent of molecular techniques, the morphological classification of ESTs can be integrated with molecular findings in enhanced classification of these tumours. In the future, the morphological and immunohistochemical features correlated with molecular categorisation of ESTs, will become a robust means to plan therapeutic decisions, especially in recurrences and metastatic disease. In this review, we summarise the morphological, immunohistochemical and molecular features of ESTs with particular reference to the most recent molecular findings.

The values of Transgelin, Stathmin, BCOR and Cyclin-D1 expression in differentiation between Uterine Leiomyosarcoma (ULMS) and Endometrial Stromal Sarcoma (ESS); diagnostic and prognostic implications

Background

Morphologic distinction between uterine leiomyosarcoma (ULMS) and endometrial stromal sarcoma (ESS) alone is not straightforward and has been shown to be challenging especially with poor differentiation, so immunohistochemistry (IHC) is often employed as an adjunct to morphology in uterine sarcoma.

Aim

We aimed to assess the diagnostic utility of Transgelin, Stathmin, BCOR and Cyclin-D1 separately and in-combinations in distinguishing ULMS from ESS, and to evaluate their prognostic value in patients with such sarcoma subtypes.

Material and Methods

We included 44 patients with uterine sarcoma. The diagnostic performances of Transgelin, Stathmin, BCOR and Cyclin-D1 were assessed in samples from all patients using immunohistochemistry.

Results

The combination of Stathmin and Transgelin expression has high sensitivity and specificity for diagnosis of LMS and differentiating it from ESS; 95.5% and associated with poor prognosis in LMS patients.

The combination of BCOR and Cyclin-D1 expression has high sensitivity and specificity for diagnosis of ESS and differentiating it from LMS; 90.9% and 95.5% respectively and associated with poor prognosis in ESS patients. The combination of Stathmin and Transgelin, BCOR and CyclinD1 expression has high sensitivity and specificity for diagnosis of LMS and differentiating it from ESS; 100%.

Conclusion

Combination of Stathmin, Transgelin, BCOR and Cycline-D1 raised the accuracy of differentiation between ULMS and ESS to 100% and has prognostic roles in such sarcomas.

Immunohistochemical Expression of Different Subtypes of Cytokeratins by Endometrial Stromal Sarcoma

Endometrial stromal sarcomas (ESS) are rare and understudied gynecologic mesenchymal neoplasms. These tumors can be confused with many other gynecologic and nongynecologic tumors due to their variegated morphologic appearance and nonspecific immunohistochemical profile. ESS can express cytokeratin (CK) and, therefore, may be misdiagnosed as carcinoma especially in extrauterine locations and when recurrence/metastasis is present. In this study, we investigated the expression of a wide spectrum of CKs consisting of AE1/3, CAM 5.2, HMCK, MNF116, CK5, CK6, CK7, CK8/18, CK14, CK17, CK19, and CK20 in 6 low-grade and 5 high-grade ESS. In addition, staining for estrogen receptor, progesterone receptor, CD10, and cyclin D1 was performed. Our results showed that CKs AE1/3, CAM 5.2, MNF116, and CK8/18 are more expressed in low-grade ESS, whereas high-grade ESS express more AE1/3 and CAM 5.2. In problematic cases, especially in recurrences or metastases, the immunohistochemical panel of antibodies AE1/3, MNF116, CAM 5.2, and CK8/18, together with other classic immunohistochemical markers CD10, cyclin D1, estrogen receptor, and progesterone receptor, may be helpful in the differential diagnosis between ESS and other gynecologic and nongynecologic malignancies.

Beyond Smooth Muscle-Other Mesenchymal Neoplasms of the Uterus

Mesenchymal tumors of the uterus comprise a heterogeneous group of neoplasms of varied biologic potential. In addition to being host to several anatomically unique entities, the uterus may contain mesenchymal neoplasms typically found elsewhere in the body. Although smooth muscle neoplasms are common, other mesenchymal neoplasms in this location are relatively rare. Many of these neoplasms exhibit morphologic overlap. In addition to a careful histomorphologic review, definitive classification frequently depends on the judicious application of ancillary immunohistochemical and molecular testing. The intent of this review is to offer a basic approach to the classification of primary uterine mesenchymal neoplasms.

Proliferative Lesions of the Endometrium of 50 Four-Toed Hedgehogs ( Atelerix albiventris)

Uteri from 50 four-toed hedgehogs ( Atelerix albiventris) with clinical signs of uterine disease were histopathologically examined. Sixteen animals (32%) were diagnosed with endometrial hyperplasia, 7 animals (14%) were diagnosed with endometrial polyp, and 27 animals (54%) were diagnosed with endometrial neoplasia. The mean ages of the animals with endometrial hyperplasia, polyp, and neoplasia were 28.7 months, 29.4 months, and 25.2 months, respectively. The neoplasms were classified into 7 endometrial mixed tumors, 12 endometrial stromal nodules, and 8 endometrial stromal sarcomas. However, the endometrial stromal nodules and endometrial stromal sarcomas often developed within or were contiguous with an endometrial polyp or mixed tumor. Interestingly, the stromal tumors and the stromal components of the endometrial polyp and mixed tumor displayed extraendometrial differentiation (eg, into adipocytes, granular cells, smooth muscle cells, and osteoid tissue). The endometrial stromal sarcomas exhibited severe cellular atypia and invaded subendometrial tissue. Immunohistochemical examinations demonstrated that the stromal cells of the hyperplastic lesions as well as the neoplastic lesions were positive for CD10, the progesterone receptor, and Wilms tumor 1. The four-toed hedgehog develops unique uterine neoplasms that are mainly composed of endometrial stromal cells and probably arise from endometrial polyps and/or mixed tumors.

Unusual Presentations of Gynecologic Tumors: Primary, Extrauterine, Low-Grade Endometrioid Stromal Sarcoma

Context.—

Low-grade endometrial stromal sarcomas, when uterine in location, are relatively easy to diagnose because of characteristic morphology and patterns of myometrial invasion. However, when they occur at extrauterine sites, they fall under the broad umbrella of small round blue cell tumors, making diagnosis challenging, especially when they have variant morphologic features and lack the characteristic pattern of invasion.

Objectives.—

To provide an insight into the sites of occurrence of low-grade endometrioid stromal sarcomas, the variant morphologic patterns, clues to diagnosis, and the usefulness of immunohistochemistry as an aid to facilitate correct diagnosis. The outcome of these tumors, in comparison with their uterine counterpart, is also discussed.

Data Sources.—

Existing peer-reviewed literature was reviewed.

Conclusions.—

Low-grade endometrioid stromal sarcoma is an uncommon neoplasm that can be misdiagnosed because of its rarity, unusual location, and presence of numerous variant histologic patterns that mimic other tumors. Knowledge of those features; consideration of this tumor in the differential diagnosis of small, round blue cell tumors at any location in a woman; and an appropriate use of immunohistochemistry can help facilitate the diagnosis.

Endometrial Stromal Sarcoma Arising in Colorectal Endometriosis

The malignant transformation of endometriosis is very uncommon. Whereas 75% of tumors arising from endometriosis arise in the ovary, location in extra-genital organs is rare and mesenchymal neoplasms are exceptional. A 47 year-old woman who underwent hysterectomy with bilateral salpingo-ooforectomy due to endometriosis 13 years before presented with abdominal pain. The magnetic resonance imaging (MRI) showed a 9.7×7.5 cm solid-cystic supravesical mass and a recto-vaginal tumor, as well as endometriotic nodules in the sigma, right parametrium and peritoneum that had significantly increased in size over a six months period. The patient underwent surgical resection of the masses. The histological study showed a low-grade endometrial stromal sarcoma (ESS) arising from endometriosis located at recotovaginal septum and affecting colonic wall and multiple peritoneal and pelvic implants. The patient received radiotherapy and aromatase inhibitors and is free of disease after a follow up of 2 years. Only 15 cases of ESS arising in endometriosis of the bowel have been reported. Tumor dissemination at diagnosis is unusual but does not imply a poor prognosis, as only one patient has died due to progression of the tumor. ESS should be included in the differential diagnosis of mesenchymal neoplasms in the intestine.

Endometrial stromal tumors: the new WHO classification

Endometrial stromal tumors are rare uterine mesenchymal neoplasms that have intrigued pathologists for years, not only because they commonly pose diagnostic dilemmas, but also because the classification and pathogenesis of these tumors has been widely debated. The current World Health Organization recognizes 4 categories of endometrial stromal tumor: endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS), and undifferentiated uterine sarcoma (UUS). uterine sarcoma. These categories are defined by the presence of distinct translocations as well as tumor morphology and prognosis. Specifically, the JAZF1-SUZ12 (formerly JAZF1-JJAZ1) fusion identifies a large proportion of ESN and LG-ESSs, whereas the YWHAE-FAM22 translocation identifies HG-ESSs. The latter tumors appear to have a prognosis intermediate between LG-ESS and UUS, which exhibits no specific translocation pattern. This review (1) presents the clinicopathologic features of endometrial stromal tumors; (2) discusses their immunophenotype; and (3) highlights the recent advances in molecular genetics which explain their pathogenesis and lend support for a new classification system.

Hemorrhagic Brain Metastasis of Endometrial Stromal Sarcoma

High-grade endometrial stromal sarcoma is a rare uterine malignancy. The cells of these tumors resemble endometrial cells in the proliferation stage, with many small plexiform arterioles. Herein we present a patient with endometrial stromal sarcoma that metastasized to the brain, along with the CT and MRI findings and a discussion of the surgical and histopathological features of the metastatic tumor. Immunohistopathological examination of the metastatic tumor showed a high mitotic rate and strong immunopositivity for CD10 and vimentin (as a mesenchymal marker); therefore, the lesion was considered to be high-grade endometrial stromal sarcoma. Due to the rarity of reported cases of metastatic brain tumors of high-grade endometrial stromal sarcoma, there isn’t a standard treatment protocol; however, metastatic tumors of high-grade endometrial stromal sarcoma match the same general concepts of brain metastasis. In addition, endometrial stromal sarcomas may be associated with hemorrhagic metastasis to the brain due to their pathologic characteristics.

Diagnostic use of immunohistochemistry in uterine mesenchymal tumors

Immunohistochemistry may be helpful in the diagnosis of mesenchymal uterine tumors. This article reviews the immunoreactions used most frequently in the diagnosis of uterine smooth muscle tumors, endometrial stromal tumors, undifferentiated endometrial sarcomas, UTROSCTs, PEComas, adenomyomas, adenosarcomas and carcinosarcomas.

Diplopia with a Cavernous Sinus Metastasis of a Remote Endometrial Stromal Tumour

Structural lesions involving the visual pathways often require tissue diagnosis to guide therapy. However, pathology is not always definitive, and a biopsy showing poorly differentiated cells poses significant difficulty in identifying the primary tumour. We report a case of metastatic disease causing cavernous sinus syndrome, in which biopsy revealed poorly differentiated tissue. The patient reported a history of a resected uterine tumour, and it was only after obtaining slides from 7 years prior that the diagnosis was made.

CD34-negative solitary fibrous tumour resistant to imatinib

A 75-year-old man presented to our hospital with multifocal thickening of the left pleura and left pleural effusion. Histology of the pleura showed uniform and bipolar spindle cells with moderate mitosis in a collagenised stroma. It further showed abundant blood vessels in a haemangiopericytoma-like pattern. These findings were strongly suggestive of malignant solitary fibrous tumour (SFT). The tumour showed negative staining for CD34. The loss of CD34 expression could imply histologically high-grade tumour, as reported previously. Imatinib, a multityrosine kinase inhibitor with targets, including platelet-derived growth factor receptor (PDGFR)-α and PDGFR-β, has antitumour activity in some patients with SFT. Unfortunately, imatinib treatment failed to control disease progression in the present case that expressed PDGFR-β, but not PDGFR-α. This report described a case of CD34-negative SFT resistant to imatinib.

Endometrial sarcomas: an immunohistochemical and JAZF1 re-arrangement study in low-grade and undifferentiated tumors

The current World Health Organization classification divides endometrial sarcomas into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma. Recent studies suggest undifferentiated endometrial sarcoma is a heterogeneous group and a subgroup with uniform nuclei is more akin to low-grade endometrial stromal sarcoma in terms of morphologic, immunohistochemical and genetic features. We classified endometrial sarcomas treated at our institution from 1998 to 2011 into low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma, the latter being further categorized into a group with either uniform or pleomorphic nuclei. Morphological features, immunoprofile and fluorescence in situ hybridization rearrangements of JAZF1 and PHF1 genes were correlated with tumor category and outcome. A total of 40 cases were evaluated comprising 23 low-grade endometrial stromal sarcomas, 10 undifferentiated endometrial sarcomas with nuclear uniformity and 7 undifferentiated endometrial sarcomas with nuclear pleomorphism. Low-grade endometrial stromal sarcomas were more often estrogen and progesterone receptor positive (83%) compared with undifferentiated endometrial sarcoma with nuclear uniformity (10%) or with nuclear pleomorphism (0%) (P<0.001). Positivity for p53 was restricted to undifferentiated endometrial sarcomas with more frequent expression in the group with nuclear pleomorphism (57%) than with nuclear uniformity (10%) (P=0.06). Ki-67 proliferation index in >10% of tumor cells more frequent in undifferentiated endometrial sarcoma than low-grade endometrial stromal sarcoma (P=<0.001). JAZF1 rearrangement was detected in 32% of low-grade endometrial stromal sarcomas and in none of the undifferentiated sarcomas. Rearrangement of PHF1 was found in two patients, one with JAZF1-PHF1 fusion. There were no significant differences in clinical behavior between undifferentiated endometrial sarcoma with nuclear uniformity versus nuclear pleomorphism. In conclusion, we found undifferentiated endometrial sarcoma subtypes and low-grade endometrial stromal sarcoma have distinct immunohistochemical and cytogentic profiles. Our data do not show any difference in clinical behavior between subgroups in undifferentiated sarcomas.

Endometrial stromal sarcoma arising from endometriosis of the terminal ileum: the role of immunohistochemistry in the differential diagnosis

Low-grade endometrial stromal sarcoma (LESS) is an uncommon uterine malignancy. Occasionally, it may develop in extrauterine endometriotic lesions and present morphological characteristics mimicking various neoplasms, making its diagnosis very challenging. We report a rare case of a 56-year-old woman presenting with a pelvic mass, initially presumed to be of ovarian origin. After surgical excision the diagnosis of a LESS arising from foci of endometriosis of the terminal ileum was established. Pelvic lymph nodes and omentum were also infiltrated. The patient received adjuvant chemotherapy and medroxyprogesterone; she is alive with no evidence of disease after a follow-up of 38 months. Immunohistochemical characteristics of the tumor are very important for the differential diagnosis of this rare neoplasm and include diffuse strong positivity for CD 10, estrogen receptor expression and CD 34 negativity.

WT1 expression in the female genital tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Metastatic endometrial stromal sarcoma of the lung: importance of immunohistochemical staining, clinical history and imaging studies

Proper evaluation of lung nodules is a difficult issue for clinical management of patients. Discriminating metastatic endometrial stromal sarcoma (ESS) from other primary spindle cell neoplasms of the lung using histological analysis can be challenging. This is particularly true when an adequate clinical history is lacking, because ESS metastasis can be delayed by a couple of decades. To emphasize the importance of the correlation of pathological findings with clinical history and imaging studies, we investigated 11 cases of ESS (seven low grade and four high grade) metastatic to the lung. All cases presented with one to multiple unilateral or bilateral lung nodules that were detected by chest computed tomography. Primary ESS was diagnosed from hysterectomy specimens except for one by endometrial biopsy, 0.5 to 23 years prior to metastasis. Immunohistochemical studies showed that all ESS cases were moderately to strongly positive for Bcl-2 and CD10 with >50% of tumor cells stained, except for one high grade ESS that was negative for CD10. Eight (72.7%) and seven (63.6) of the 11 cases showed positive estrogen and progesterone receptors, respectively, with a majority of positive cases showing diffuse and moderate to strong staining. Strong but patchy staining for CD34 was detected in one (9.1%) case with smooth muscle differentiation. CK7 and TTF-1 were negative in all cases. Two (18.2%) cases exhibited patchy and strong positivity for caldesmon. Two (18.2%) low grade ESS cases showed moderate to strong AE1/AE3 positivity in >50% of tumor cells, one of which also showed moderate CK19 and Cam 5.2 staining in >30% of tumor cells. One should be cautious when assessing spindle cell neoplasms of the lung in women with a history of hysterectomy. Correlation of clinical history and imaging studies with histological and immunohistochemical findings is essential to diagnosis of metastatic ESS to the lung.

Endometrial stromal sarcoma with selective polyvinyl alcohol embolization of a pulmonary metastasis after recurrent hemoptysis and expansive growth

A 63-year-old female with a well-vascularized pulmonary metastasis of an endometrial stromal sarcoma (ESS) of 6×6 cm received selective embolization with 150-250 μm polyvinyl alcohol (Contour; Boston Scientific, Natick, MA, USA) via a bronchial artery. Post-interventional loss of perfusion was qualitatively estimated to be >80%. The lesion was located in direct proximity to the pulmonary hilar vessels. Owing to recurrent and sudden hemoptyses, an interdisciplinary tumor board assessed the risk of life-threatening blood loss to be greater than that of angiography with particle embolization and agreed on an endovascular approach. Hemoptysis did not recur in a follow-up period of six months. Initial clinical symptoms were noted 25 years ago. However, establishing a definite diagnosis has, for a long time, remained a histopathological challenge.

Endometrial/ioid Stromal Tumors and Related Neoplasms of the Female Genital Tract

Endometrial/ioid stromal tumors comprise a spectrum of mesenchymal neoplasms, ranging from benign to low-grade malignancy to undifferentiated sarcomas, which occur predominantly in the uterus but may rarely originate at extrauterine sites, most commonly in the ovary. These tumors and their morphologic variants are important to recognize as they often cause diagnostic difficulties. This review focuses on the diagnostic criteria and differential diagnosis, including the role of immunohistochemistry.

Immunohistochemical Markers of Value in the Diagnosis of Mesenchymal Lesions of the Female Genital Tract

Pure mesenchymal tumors may occur anywhere in the female genital tract, but they are most common in the uterine corpus, leiomyoma being by far the most prevalent. These tumors, and other uncommon mesenchymal lesions within the uterine corpus and elsewhere in the female genital tract, may result in several diagnostic problems. Morphology remains paramount and, in most cases, an unequivocal diagnosis can be made based on examination of the hematoxylin and eosin stained sections, combined with an appreciation of the clinical and gross pathologic features. In difficult cases, immunohistochemistry can significantly contribute to the final diagnosis. In this article, the immunohistochemistry of neoplastic and nonneoplastic mesenchymal lesions of the female genital tract is discussed site by site, concentrating on markers that are of value in diagnosis and in differential diagnosis. The immunophenotype of mixed epithelial and mesenchymal neoplasms and pure epithelial neoplasms with a component of spindle cells is discussed, where appropriate, because these can enter into the differential diagnosis of a pure mesenchymal lesion.

Calretinin: diagnostic utility in the female genital tract

The utility of calretinin was first described in the diagnosis of mesothelioma. In the female genital tract, calretinin was initially reported in Wolffian remnants and related lesions and later used in the diagnosis of sex cord stromal tumors of the ovary, endometrial stromal tumors with sex cord-like differentiation, and uterine tumors resembling sex cord tumors of the ovary. This review discusses calretinin expression in normal tissues of the female genital tract and highlights its potential utility in the diagnosis of these subsets of neoplasms with emphasis to tumors that may constitute a problem in their differential diagnosis. In particular, the limited utility of calretinin in the diagnosis of sex cord stromal tumors of the ovary, in the differential diagnosis between mesothelioma and serous tumors involving the ovary and/or peritoneum, and in the differential diagnosis between Wolffian lesions and endometrial carcinoma are addressed.

Pulmonary Stenosis due to Right Ventricular Outflow Tract Metastasis from a Uterine Sarcoma

A 50 year-old woman presented with dyspnoea and symptoms and signs of systemic venous congestion. Examination revealed murmur of pulmonary stenosis. Echo-Doppler, CT scanning and Magnetic Resonance Imaging showed a large right ventricular tumour obstructing the right ventricular outflow tract. She had a hysterectomy for menorrhagia 9 years previously, and resection of a lump involving the right trapezius a month prior to her deterioration. Pathology demonstrated low-grade endometrial stromal sarcoma. She deteriorated acutely in hospital due to pulmonary embolism from superimposed thrombosis. Anticoagulation, followed by radiotherapy resulted in marked clinical improvement. Two years later, the patient remains well. Cardiac metastasis from ESS is rare. Diagnosis is established by echocardiography, CT and cardiac MRI, which allow structural and functional evaluation of the tumour. MRI seems to be the most useful modality. Treatment is palliative or curative resection. This is the first case report of cardiac ESS showing good response and prolonged survival after radiotherapy. Prophylactic anticoagulation should be considered as pulmonary embolism can cause marked deterioration.

Mullerian adenosarcomas: an immunophenotypic analysis of 35 cases

Mullerian adenosarcomas (MAs) are rare mixed mesenchymal and epithelial neoplasms that occur most commonly in the uterus. Although the epithelial component is typically benign, the mesenchymal component of most adenosarcomas morphologically resembles that observed in endometrial stromal tumors and is responsible for their clinical behavior. Thus, the differential diagnosis usually includes not only low-grade endometrial stromal tumors, but also adenofibroma, carcinosarcoma, and embryonal rhabdomyosarcoma especially in small samples. The objective of this study was to ascertain the immunophenotypic profile of the epithelial and mesenchymal components of MAs and delineate possible differences between conventional mesenchymal areas and areas of sarcomatous overgrowth. Representative sections from 35 MAs, 28 of them without sarcomatous overgrowth (MA-NSO) and 7 with sarcomatous overgrowth (MA-SO), were included in the study. Thirty tumors arose in the uterus, 4 were pelvic, and 1 originated in the colon. Adequate blocks were selected and immunostained for estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), CD10, WT1, smooth muscle actin, desmin, AE1/3 cytokeratin, CD34, calretinin, inhibin, c-kit, and Ki-67. The mesenchymal component expressed ER in 21/27 MA-NSOs but in only 1/7 MA-SOs (65% overall). PR was expressed in 21/26 MA-NSOs and 4/7 MA-SOs (76% overall), whereas AR was positive in 10/27 MA-NSOs and 5/7 MA-SOs (35% overall). CD10 was expressed in 23/28 MA-NSOs but in only 2/7 MA-SOs (71% overall), and WT1 positivity was seen in 22/27 MA-NSOs and 6/7 MA-SOs (79% overall). Sixty-seven percent of MAs expressed smooth muscle actin, 32% desmin, including both examples of MA-SOs with rhabdomyoblastic differentiation, and 25% expressed AE1/3 cytokeratin. CD34 expression was found in 35% of the tumors, but it was almost always patchy in distribution and weak in intensity, as was calretinin expression, seen only in 12% of the cases. Expression of c-kit and inhibin in greater than 5% of the tumor cells was not encountered. The median and mean Ki-67 labeling indices were 10% and 12%, respectively (range, <5% to 40%). The median and mean Ki-67 indices were both 5% in MA-NSOs compared with 30% and 28%, respectively, in MA-SOs. The epithelial compartment demonstrated expression for ER (24/32), PR (23/31), and AE1/3 cytokeratin (33/33); rare cases expressed CD10 (4 cases) and AR (1 case). In summary, the immunophenotype of most MAs resembled that of endometrial stromal tumors (positive for ER, PR, WT1, and CD10, with variable expression of muscle markers, AR and cytokeratin). The proliferative rate in the stromal component was strongly related to the presence of sarcomatous overgrowth. ER, PR, and CD10 expression was lost in MA-SOs relative to conventional low-grade stromal areas of mullerian/mesodermal adenosarcomas, reflecting the "dedifferentiation" of this component.

Immunohistochemical profiling of cytokeratin expression by endometrial stroma sarcoma

Endometrial stromal sarcomas can be confused with several neoplasms because of their inconsistent and widely varied morphologic appearance and frequent immunohistochemical expression of a variety of antigens including cytokeratin. The resulting diagnostic challenge becomes problematic particularly in the diagnosis of metastases resulting from such tumors. Because of the sometime epithelioid appearance of the tumor cells and their expression of cytokeratin, the metastases may be misdiagnosed as poorly differentiated carcinoma. We therefore studied the profile of cytokeratin proteins expression in 17 cases of endometrial stromal sarcomas using a panel of antibodies including cytokeratin cocktail antibody (AE1/AE 3), CK5/6, CK7, CK14, CK16, Cam5.2 (CK8), CK19, CK20, and 34Ebeta12 (CK1, 5, 10, and 14). Of the 17 cases, 8 (47%) stained positive with the cytokeratin cocktail antibody (AE1/AE 3). Of the 8 cases with cytokeratin expression, 5 (63%) stained positive with CK19, and 3 of them stained positive with Cam5.2. The 3 cases that stained positive with Cam5.2 also expressed CK19. Of the 5 cases with CK19, 1 was focally positive for CK5/6, CK7, and 34Ebeta12. None of the cases expressed CK14, CK16, or CK20. These results show that CK19 is most commonly expressed cytokeratin in endometrial stromal tumors. Hence, the inclusion of CK19 in the panel of immunostains may help resolve the diagnostic confusion created by keratin expression in endometrial stromal sarcoma and may also help in the correct diagnosis of endometrial stromal sarcoma at extrauterine sites.

Application of immunohistochemistry to gynecologic pathology

CONTEXT

A large variety of tumors and lesions arise in the female genital tract. Although the majority of these can be correctly recognized on routine hematoxylin-eosin-stained slides, occasional cases present a diagnostic challenge. Immunohistochemical stains are extremely useful in resolving many of these problematic cases. As the knowledge in this area is constantly expanding, it is useful to have this updated information in a review form for easy access.

OBJECTIVE

To present our current knowledge of immunohistochemistry of the lesions of the female genital tract in a readily accessible form.

DATA SOURCES

The review is based on previously published articles on this topic.

CONCLUSIONS

Immunohistochemical stains help in reaching a conclusive diagnosis in a variety of problematic lesions seen in gynecologic pathology. As in any other system, immunohistochemical findings need to be interpreted in light of the clinical history and morphologic findings.

Subpial hemangiopericytoma with marked extramedullary growth: case report

OBJECTIVE

Hemangiopericytomas, vascular tumors arising in soft tissue, are relatively rare in the central nervous system; they comprise less than 1% of all hemangiopericytomas. Central nervous system hemangiopericytomas occur primarily in the epidural space of the brain and spinal cord. There are no previous reports of subpial, extramedullary growing central nervous system hemangiopericytomas.

CLINICAL PRESENTATION

We document the first case of a subpial hemangiopericytoma with extramedullary growth in the thoracic spine. The patient was a 31-year-old man who developed progressively worsening left lower limb numbness that was followed by gait disturbance over the course of 4 months.

INTERVENTION

Magnetic resonance imaging revealed an intradural tumor at the T4-T6 level of the thoracic spine. Because the patient's symptoms progressed, he underwent resection of the tumor, which had arisen in the spinal cord subpially without attachment to the dura mater.

CONCLUSION

The pathological diagnosis was hemangiopericytoma. Differential diagnoses include hemangioblastoma, meningioma, schwannoma, and solitary fibrous tumor, the clinical course and prognosis of which are different from hemangiopericytoma. Our experience indicates that hemangiopericytomas can occur as intradural tumors arising from the subpial portion.

High Frequency of JAZF1-JJAZ1 Gene Fusion in Endometrial Stromal Tumors With Smooth Muscle Differentiation by Interphase FISH Detection

The most common cytogenetic alteration observed in low-grade endometrial stromal tumors (EST) is the t(7;17)(p15;q21) translocation, resulting in the fusion of the JAZF1 and JJAZ1 genes. By reverse-transcription polymerase chain reaction, the translocation has been detected overall in one-third of ESTs, but only rarely in its variants. The purpose of this study was to develop a fluorescence in situ hybridization assay for detection of this translocation using archival paraffin-embedded samples of ESTs with smooth muscle differentiation and to assess the nature of the smooth muscle component of these tumors. Representative paraffin blocks of 9 endometrial stromal nodules and 1 low-grade endometrial stromal sarcoma were collected for the study. In 1 case, the block selected also contained areas of sex cordlike differentiation. A fluorescence in situ hybridization probe set was designed to detect the t(7;17)(p15;q12) on tissue sections. Six out of 10 collected ESTs were assessable. Fusion signals were detected in 3 out of 6 cases (50%) in both the conventional endometrial stromal and the smooth muscle components of the tumors. The tumor sample with sex cordlike differentiation harbored the fusion signal in all the 3 components. Our results support the contention that the endometrial stromal and smooth muscle components of these tumors have the same origin, either from a common precursor cell with pluripotential differentiation or from endometrial stromal cells that have undergone smooth muscle metaplasia. Our results indicate that the detection of this chromosomal abnormality can be used to diagnose ESTs with smooth muscle differentiation when the smooth muscle component is predominant.

Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis

Over the last decade, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure gastrointestinal mesenchymal tumors to well-defined tumors with distinctive clinical, morphologic, ultrastructural, histogenetic, and molecular characteristics, for which targeted therapy is available. This is largely attributable to the discovery of CD117 overexpression and activating mutations in c-kit or platelet-derived growth factor alpha genes in most of GISTs. The availability of specific diagnostic tests and targeted therapy for GISTs has led to an increased awareness of these tumors. At the same time, the list of potential GIST mimics has lengthened considerably and it has become increasingly important that GISTs be distinguished from their mimics because correct diagnosis has implications for both treatment and prognosis. The purpose of this review is to provide an update of the expanding differential diagnosis of GISTS, to draw attention to unusual GIST variants, to provide a practical approach the differential diagnosis of GISTs and to highlight some of the challenges faced by pathologists in resolving this differential diagnosis.

Immunohistochemical and functional biomarkers of value in female genital tract lesions

There has been a marked expansion in the literature pertaining to the use of immunohistochemical markers in female genital tract pathology, especially with regard to diagnosis. This review provides a survey of the antibodies commonly used in the diagnosis of gynecological lesions grouped as to function or type. Prognostic or predictive markers are also discussed where appropriate, although few of these are of value in everyday practice. It is stressed that when immunohistochemistry is used diagnostically, panels of markers provide better information than reliance on a single antibody.

Immunohistochemistry as a diagnostic aid in the evaluation of ovarian tumors

Aspects of immunohistochemistry (IHC), which are useful in the diagnosis of ovarian tumors (mostly neoplasms but also a few tumor-like lesions), are discussed. The topic is first approached by considering the different growth patterns and cell types that may be encountered. Then a few other specific situations in which IHC may assist are reviewed. Selected findings largely, or only, of academic interest are also mentioned. One of the most common situations in which IHC may aid is in the evaluation of tumors with follicles or other patterns which bring a sex cord-stromal tumor into the differential. The distinction between a sex cord tumor and an endometrioid carcinoma with sex-cord-like patterns may be greatly aided by the triad of epithelial membrane antigen (EMA), inhibin, and calretinin, the latter two being typically positive and EMA negative in sex cord tumors, the converse being typical of endometrioid carcinoma. It should be emphasized that granulosa cell tumors may be inhibin negative and, albeit less specific, calretinin is more reliable in evaluating this particular issue. Lack of staining for inhibin and calretinin may also be supportive in leading to consideration of diverse other neoplasms that may form follicles, including metastatic tumors as varied as carcinoid and melanoma. The well-known staining of the latter neoplasm for S-100 protein and HMB-45 may be very helpful in evaluating melanomas with follicular or other unusual patterns, a challenging aspect of ovarian tumor interpretation. The most common monodermal teratoma, struma ovarii, usually has an overt follicular pattern and is easily recognized, but recognition of unusual appearances ranging from oxyphilic to clear cell to various patterns of malignant struma may be greatly aided by a thyroglobulin or TTF 1 stain. IHC for neuroendocrine markers may assist in the diagnosis of primary and metastatic carcinoid tumor. The broad differential diagnosis of glandular neoplasms with an endometrioid-pseudoendometrioid morphology, or mucinous cell type, has been the subject of much exploration in recent years, particularly the distinction between primary and metastatic neoplasms. The well-known CK7 positive, CK20 negative phenotype of primary endometrioid carcinoma, and the converse profile in most metastatic large intestinal adenocarcinomas with a pseudoendometrioid morphology, has been much publicized but albeit an appropriate supportive adjunct in many cases, exceptions from the typical staining pattern may be encountered. It is even less helpful in the case of primary versus metastatic mucinous neoplasia. Evaluation of the expression of mucin gene products has shown mixed, essentially unreliable, results. Experience with other new markers, such as CDX-2, villin, beta catenin, and P504S (racemase), is limited but is in aggregate promising with regard to providing some aid in this area. The rare differential of metastatic cervical adenocarcinoma versus primary ovarian mucinous or endometrioid carcinoma may be aided by strong p16 staining of the former. Staining for alpha-fetoprotein may aid in confirming the diagnosis of endometrioid-like (and hepatoid) variants of yolk sac tumor. Ependymoma of the ovary may also have an endometrioid-like glandular pattern, but positive stains for glial fibrillary acidic protein contrast with the negative results in others neoplasms with a similar pattern. Immunostains may be very helpful in the evaluation of oxyphilic tumors and tumor-like lesions and in some unusual forms of clear cell neoplasia, such as clear cell struma, both subjects being reviewed herein. Immunostains may highlight both the presence and extent of epithelial cells in a variety of circumstances, including microinvasive foci in cases of serous borderline tumors and mucinous carcinomas, and in determining the extent of carcinoma cells and reactive cells within mural nodules of mucinous neoplasms. As in tumor pathology in general, various markers may be crucial in the diagnosis of small round cell tumors of the ovary, and familiar markers of epithelial, lymphoid, leukemic, and melanocytic neoplasms may assist in the analysis of high grade tumors with a poorly differentiated carcinoma, lymphoma-granulocytic sarcoma, malignant melanoma differential. The evaluation of ovarian cystic lesions may be aided by thyroglobulin or TTF 1 (cystic struma), glial fibrillary acid protein (ependymal cysts), and inhibin-calretinin (follicle cysts and unilocular granulosa cell tumors). Stains for trophoblast markers may occasionally aid in the evaluation of germ cell tumors, although routine stains should usually suffice; they may be of academic interest in confirming trophoblastic differentiation in some high grade surface epithelial carcinomas.