Perivascular epithelioid tumours (PEComas) of the gynaecological tract

Risk Stratification of Miscellaneous Uterine Mesenchymal Neoplasms: The Role of Morphology, Immunohistochemistry, and Molecular Testing

Uterine mesenchymal tumors are a diverse group of tumors that can display a broad range of morphologic, immunohistochemical, and molecular profiles and are associated with varied clinical behaviors. In recent years, they have increasingly been classified by their underlying molecular alterations, leading to a more precise separation of diagnostic entities. As their diagnostic criteria have been refined, so too have the features that can be used to predict clinical outcomes. This review includes a discussion of uterine inflammatory myofibroblastic tumors, perivascular epithelioid cell tumors (PEComa), and uterine tumors resembling ovarian sex cord tumors, with a focus on updates on their clinical behavior and tools for risk stratification to identify malignant tumors. In addition, we discuss the importance of using an integrated approach when classifying uterine mesenchymal tumors to improve diagnostic accuracy and guide clinical management.

[Translocation-associated uterine mesenchymal tumors: The new without forgetting the old. An integrated diagnostic approach]

This review focuses on uterine mesenchymal tumors that are defined on a molecular level by a single and unique genetic alteration, that is somehow necessary and sufficient to allow tumor growth and progression. Although diverse from a clinical, morphological and immunohistochemical point of view, the different entities we are going to talk about share both a simple genomic profile with a low number of chromosomal alterations observed by CGH Array (few deletions, gains or amplifications...) and a low mutational burden observed by sequencing technics. Some of these entities are already well known and described in the literature when found outside of the uterus and gynecological tract. It remains intriguing that uterine mesenchymal pathology has been lagging behind when compared to its extrauterine counterpart. How can we explain that when it comes to inflammatory myofibroblastic tumors, abundant numbers of articles have been published since the 70's, but it was only in the early 2000s that the first relevant descriptions of this tumor in the uterus emerged? Certainly, the increased accuracy, availability, and use of molecular biology technics and in particular RNA sequencing in the area of uterine pathology can partly explain the reduction of the gap between soft tissue and uterine pathology we currently observe. Other reasons explaining this gap may be the high prevalence of smooth muscle tumors in the uterus and the abounding diversity of their morphological aspects, which may have partly eclipsed the array of differential diagnoses. Last but not least, one can hypothesize that the relative "simplicity" of hysterectomy procedures, referring to their safety and accessibility, has cured most of the lesions and partly clouded our knowledge regarding the biological potential and natural history of these newly described entities. As a consequence of this situation, our reader will often encounter the wording "uncertain malignant potential", as for some of these rare entities, evidence to establish reliable prognostic variables is still insufficient. We hope this review to be a useful tool to guide pathologists through the diversity and complexity of uterine mesenchymal tumors. As a scientific and medical community, sharing this knowledge will help us to collectively raise our vigilance and awareness by expanding the array of our differential diagnoses. We hope this will lead to more cases being accurately diagnosed, and ultimately, to a deeper knowledge regarding the biological potential and clinical evolution of these tumors. From a therapeutical point of view, the consequences of an accurate diagnosis for the patient are already appreciable through the use of targeted therapy. Examples include: ALK inhibitors in inflammatory myofibroblastic tumor, tyrosine-kinase inhibitors in COL1A::PDGFB rearranged sarcomas or mTOR inhibitors in PEComa.

Malignant Perivascular epithelioid cell tumour of the uterus without TFE3 gene rearrangement: a case report

BACKGROUND

Perivascular epithelioid cell tumours (PEComas) are soft tissue tumours. These neoplasms belong to the family of mesenchymal tumours, which include angiomyolipomas, clear-cell sugar tumours of the lung, and PEComas not otherwise specified (NOS). The probability of a perivascular epithelioid cell tumour (PEComa) occurring in the uterus is low, and the incidence, diagnosis, treatment, and outcomes of such tumours are still unclear.

CASE PRESENTATION

A 51-year-old woman presented a 4-year history of natural menopause. An intrauterine mass was detected via ultrasound examination; the mass showed a tendency to increase but caused no symptoms. The levels of tumour markers were within the normal range. Pathological analysis of the curettage revealed perivascular epithelioid differentiation of the endometrial tumour. Consequently, a laparoscopic total hysterectomy with bilateral adnexectomy was performed. No distant metastasis was detected via whole-body positron emission computed tomography (PETCT) after the operation. Fluorescence in situ hybridization (FISH) revealed no TFE3 gene rearrangement. Next-generation sequencing of bone and soft tissue revealed negative TSC1/2 and TP53 expression. No recurrence or metastasis was observed during the 18-month follow-up period.

CONCLUSION

PEComa of the gynecologic tract is a rare and challenging entity. Diffuse HMB-45 expression, TSC alterations and TFE3 rearrangement are characteristic of uterine PEComas. Surgical resection is the first choice. Genetic testing is helpful for determining the nature of the mass and for choosing targeted therapy. Further research is needed to establish treatment protocols.

Uterine perivascular epithelioid cell tumors (PEComa) and the accuracy of proposed classification systems in predicting the malignant versus non-malignant behavior

OBJECTIVE

To compare the accuracy of available classification systems (Folpe, modified Folpe, Bennet, and Schoolmester) in predicting the behavior of uterine Perivascular Epithelioid Cell tumors (PEComas).

METHODS

We reviewed the pathology registry to identify all uterine PEComas treated at our center. We conducted a systematic literature review searching electronic databases from inception to November 2023. We included all references reporting at least one case of uterine PEComa; cases associated with tuberous sclerosis complex were excluded. Patient-level data were extracted by identified records. Survival analysis was used to assess the accuracy of all proposed classification systems to classify uterine PEComas as malignant versus non-malignant.

RESULTS

Six uterine PEComas were treated at our center. The literature search identified 101 uterine PEComas from 32 studies. Eighty-five out of 107 PEComas (28 studies and our series) reported enough follow-up data and details to apply all four classifications. The modified Folpe classification demonstrated the highest hazard ratio (HR) for relapse (HR:8.63; 95% confidence interval [CI] 2.06-36.1) and death due to PEComa (HR:6.8, 95%CI:0.89-51.6) for malignant versus non-malignant PEComas. Changing the cut-off of PEComa size to ≥8 cm and mitotic figures per 50 high power fields to ≥5, the HR for recurrence lowered (HR:6.26; 95% CI 2.20-17.80), but HR for death increased (HR:10.3; 95% CI 1.35-77.80).

CONCLUSIONS

The modified Folpe classification was the most accurate in predicting the PEComa behavior. Changing the cut-off of PEComa size and number of mitotic figures may improve the accuracy in predicting death due to disease.

The evolving landscape of immunohistochemistry in cervical and uterine carcinoma in gynecologic oncology: current status and future directions

Immunohistochemistry (IHC) has become an indispensable tool in routine gynecological pathology, particularly with the advancements in molecular understanding and histological classification of gynecological cancers. This evolution has led to new immunostainings for diagnostic and classification purposes. This review describes the diagnostic utility of IHC in gynecological neoplasms, drawing insights from literature reviews, personal experiences, and research findings. It delves into the application of IHC in resolving morphologically equivocal cases, emphasizing its role in achieving an accurate diagnosis. The selection of appropriate immunomarkers for common scenarios encountered in gynecological pathology aids pathologists in navigating complex cases. Specifically, we focus on cervical and endometrial malignancies, elucidating the molecular rationale behind the use of specific immunohistochemical markers. An updated overview of essential immunohistochemical markers provides knowledge for precise diagnosis and classification of gynecological cancers. This review serves as a valuable resource for clinicians and researchers involved in the management and study of gynecological malignancies, facilitating improved patient care and outcomes.

Challenges in Diagnosing Metastatic Uterine PEComa: Insights from Two Case Studies

BACKGROUND Perivascular epithelioid cell tumor (PEComa) is usually a benign perivascular tumor that expresses both melanocytic and myogenic cell markers. We report 2 cases of advanced malignant uterine perivascular epithelioid cell tumor (PEComa) in a 74-year-old woman and a 50-year-old woman undergoing surgery in our center. CASE REPORT Case 1: A 74-year-old woman presented with a painful and massive abdominal mass. The imaging revealed a 19-cm necrotic mass close to the mesentery, a suspicious lesion in the uterus, and a probable liver metastasis. The pathological diagnosis was quite difficult with mixed features of leiomyosarcoma and PEComa with an uncommon immunohistochemistry staining pattern. Therefore, we gave a diagnosis of sarcoma with PEComa-like features. Case 2: A 50-year-old woman with metrorrhagia and abdominal pain. Imaging revealed a 7-cm mass in the uterus and suspicious metastatic lesions in the lung and the liver. The immunohistochemistry pattern was typical, with a strong positivity of Human Melanoma Black-45 (HMB-45) and focal positivity of H-Caldesmon. The patient benefited from targeted adjuvant therapy (MTOR inhibitor-based), with 8-month a follow-up showing no recurrence for this Grade IV PEComa mutated for TP53, ATRX, and TSC1. CONCLUSIONS We have report 2 cases of metastatic PEComa with different clinicopathological features. An overlap remains between characteristics of PEComas and smooth-muscle tumors. At present, there are no known pathognomonic findings or specific diagnostic markers.

Staining pattern of specific and cross-reacting Melan-A antibodies: A comparative study on 15,840 samples from 133 human tumor types

The Melan-A (melanocyte antigen) protein, also termed 'melanoma antigen recognized by T cells 1' (MART-1) is a protein with unknown function whose expression is specific for the melanocyte lineage. Antibodies against Melan-A are thus used for identifying melanocytic tumors, but some Melan-A antibodies show an additional - diagnostically useful - cross-reactivity against an unspecified protein involved in corticosteroid hormone synthesis. To comprehensively compare the staining patterns of a specific and a cross-reactive Melan-A antibody in normal and neoplastic tissues, tissue microarrays containing 15,840 samples from 133 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. For the Melan-A-specific antibody 'Melan-A specific' (MSVA-900M), Melan-A positivity was seen in 96.0% of 25 benign nevi, 93.0% of 40 primary and 86.7% of 75 metastatic melanomas, 82.4% of 85 renal angiomyolipomas as well as 96.4% of 84 neurofibromas, 2.2% of 46 granular cell tumors, 1.0% of 104 schwannomas, and 1.1% of 87 leiomyosarcomas. The cross-reactive antibody 'Melan-A+' (MSVA-901M+) stained 98.1% of the tumors stained by 'Melan-A specific'. In addition, high positivity rates were seen in sex-cord-stroma tumors of the ovary (35.3%-100%) and the testis (86.7%) as well as for adrenocortical neoplasms (76.3%-83.0%). Only nine further tumor groups showed Melan-A+ staining, including five different categories of urothelial carcinomas. Our data provide a comprehensive overview on the staining patterns of specific and cross-reactive Melan-A antibodies. The data demonstrate that both antibodies are highly useful for their specific purpose. It is important for pathologists to distinguish these two Melan-A antibody subtypes for their daily work.

Soft Tissue Perivascular Epithelioid Cell Tumors

Perivascular epithelioid cell tumors (PEComas) are a heterogenous group of mesenchymal neoplasms with a mixed myomelanocytic immunophenotype. PEComa-family tumors include angiomyolipoma, lymphangioleiomyomatosis, and a large category of rare neoplasms throughout the body that are now classified under the umbrella term "PEComa." This review focuses on recent advances in the clinicopathological and molecular features of PEComas, with an emphasis on PEComas that originate in soft tissue.

Systematic analysis of perivascular epithelioid cell neoplasms in the female reproductive tract: a comprehensive review

Perivascular epithelioid cell neoplasms (PEComas) are rare mesenchymal lesions, with gynecological PEComas accounting for just over a quarter of cases. Limited reports exist on gynecological PEComa, primarily treated with surgery; adjuvant therapy is considered in high-risk cases. This systematic review aims to summarize the origin and clinical, pathological and molecular characteristics of uterine PEComa, focusing on treatment options for gynecological PEComa. A comprehensive PubMed review of gynecological PEComa reports was conducted. A detailed examination of the literature ensured a thorough understanding. Gynecological PEComa diagnosis relies on histology and immunology. Despite therapy controversies, surgery remains the mainstay. Adjuvant therapy efficacy in high-risk cases is uncertain. mTOR inhibitors are the first line; alternative treatments, including angiogenesis and aromatase inhibitors, should be considered.

Comparison of 18 F-FDG and 68 Ga-FAPI PET/CT in a Patient With Hepatic Perivascular Epithelioid Cell Neoplasm

ABSTRACT

The prevalence of hepatic perivascular epithelioid cell neoplasm (PEComa) is extremely low, and imaging diagnosis is very difficult. We presented 18 F-FDG and 68 Ga-FAPI PET/CT findings in a 58-year-old woman with pathologically confirmed hepatic PEComa. The tumor showed intense 68 Ga-FAPI uptake but only mild 18 F-FDG activity on PET/CT studies. This case suggested that 68 Ga-FAPI PET/CT might be a useful tool for evaluation of hepatic PEComa with remarkable tumor-to-liver ratios.

Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissue: a Japanese Musculoskeletal Oncology Group (JMOG) multi-institutional study

PURPOSE

Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissues are rare mesenchymal neoplasms, some of which are malignant. However, their clinical and pathological characteristics remain unclear. This study was performed to investigate the clinical and pathological characteristics of PEComas in bone and soft tissues by leveraging information from the Japanese Musculoskeletal Oncology Group.

METHODS

Nine patients, including four male and five female patients with a median age of 50 years, were retrospectively reviewed. PEComas of the visceral organs, including the uterus and retroperitoneum, were excluded.

RESULTS

Eight tumors arose in the soft tissue and one in the bone, with a mean size of 8.8 cm. Four patients showed local recurrence or distant metastasis. The 1-year survival rate was 78%. Pathologically, eight tumors were classified as malignant and one as having uncertain malignancy potential. Half of the tumors showed high MIB-1 index values of > 30%. Immunohistochemically, the melanocyte marker HMB45 was expressed in 89% of the cases, and muscle-specific markers were expressed only in 30-50% of the cases. Transcription factor binding to IGHM enhancer 3 (TFE3) expression was positive in 100% of the patients. Tumors with high expression of TFE3 were classified as PEComas with malignant potential according to Folpe's classification.

CONCLUSIONS

Bone and soft tissue PEComas may have a higher malignancy potential than other visceral PEComas and are more likely to develop as TFE3-rearranged PEComas.

Cervical PEComa: Challenges in diagnosis and prognosis of a rare neoplasm

•Cervical PEComas are rare neoplasms which present a diagnostic challenge.•Large tumour size is an important clinical prognosticator in cervical PEComa.•All reported cases of cervical PEComa classified as benign by Folpe criteria behaved in benign fashion clinically.•Tumours ≤ 4 cm may be assessed with cone biopsy, and simple hysterectomy considered if no adverse pathologic features.•Molecular characterization and linkage with coordinated rare tumour registries may identify novel treatments.

A Clinicopathologic and Molecular Characterization of Uterine Sarcomas Classified as Malignant PEComa

Perivascular epithelioid cell tumors (PEComas) are a distinctive group of mesenchymal neoplasms that demonstrate features of smooth muscle and melanocytic differentiation. Here, we present the clinicopathologic, immunohistochemical, and molecular features of 15 uterine sarcomas diagnosed as malignant PEComa. The median patient age was 56 years (range: 27 to 86 y). The median tumor size was 8.0 cm (range: 5.0 to 14.0 cm). All tumors were classified as malignant based on the presence of mitoses (15/15; 100%), necrosis (15/15; 100%), lymphovascular invasion (8/15; 53%), and high nuclear grade (13/15; 87%). Molecular analysis revealed the mammalian target of rapamycin pathway gene mutations in 7 cases (47%), including mutually exclusive variants in TSC1 (27%) and TSC2 (20%). Recurrent alterations were also identified in TP53 (53%), RB1 (30%), ATRX (33%), and BRCA2 (13%). Tumors with inactivating ATRX mutations all demonstrated loss of ATRX expression by immunohistochemistry. Loss of expression was also observed in 2 tumors without demonstrable ATRX alterations. Clinical follow-up was available for 14 patients (range: 5 to 92 mo; median: 15 mo). Five patients developed local recurrence and 9 developed metastases; 2 patients died of their disease. Our series expands the spectrum of molecular events in tumors diagnosed as malignant PEComa and further highlights the important role of targeted sequencing in tumors with focal melanocytic marker expression.

Risk stratification and outcomes in 210 gynecologic perivascular epithelioid cell tumors (PEComas) cases

OBJECTIVE

To better understand the risk stratification and outcomes of gynecologic PEComas.

METHODS

Clinicopathological features and outcomes of gynecologic PEComas cases reported in both English and Chinese literature before September, 2020 were evaluated. The efficacy of three proposed criteria were compared to verify their practicability in gynecologic PEComas. The Chi-square test and Cox proportional hazard model were performed for statistical analysis.

RESULTS

A total of 210 cases were retrieved: 95 from English literature and 115 from Chinese literature. The Flope criterion achieved an accuracy of 47% for detecting malignancy of gynecologic PEComas, 64.2% for the Schoolmeester criterion, and 63.8% for the WHO criterion. Both Chi-square test and uni-variate analysis showed that tumor size ≥ 5 cm, infiltrative growth pattern, mitotic rate ≥ 1/50 high per filed (HPF), high nuclear grade and cellularity, necrosis, and vascular invasion were significantly related to recurrence and/or metastasis (R/M) of gynecologic PEComas. Still only high mitotic rate (≥ 1/50 HPF), high nuclear grade and cellularity, and necrosis significantly influenced the long-term survival. Multi-variate analysis showed high nuclear grade and cellularity was an independent risk factor for R/M of gynecologic PEComas. No model was fitted for the death rate due to a small number of events. When defined malignant PEComas cases as meeting three or more out of six clinicopathologic features, the accuracy of such attempt was 62%, but the false-negative rate dropped by 37-55%.

CONCLUSIONS

Gynecologic PEComas with three or more high-risk factors may be considered as malignant. Further efforts should be invested to look for new potential prognostic factors.

Malignant Perivascular Epithelioid Cell Tumor (PEComa) of the Uterus as Part of the Hereditary Cancer Syndrome: A Case Diagnosed with Multiple Malignancies

A perivascular epithelioid cell tumor (PEComa) is an uncommon mesenchymal tumor composed of perivascular epithelioid cells. These tumor cells show variable immunoreactivity for both melanocytic and myogenic markers. Occurrence of PEComa has been reported at various anatomical sites, including the gynecological tract, uterus being the most common. Although most patients have sporadic PEComas, a subset may be associated with the inactivation of TSC1 or TSC2 genes and the occurrence of TFE3 gene fusions. However, a relationship between PEComas and other tumors is rare. We report a 41-year-old female patient with malignant PEComa who was admitted to the hospital with a complaint of vaginal bleeding. Because she had previously been diagnosed with colorectal and breast carcinomas at an early age, we performed a comprehensive genetic analysis to identify molecular alterations present in her background that unveiled multiple malignancy predispositions. Next-generation sequencing (NGS) analysis revealed two heterozygous germline pathogenic variants in the ATM and TP53 genes and a heterozygous variant of unknown significance (VUS) in the BRCA2 gene. The patient was diagnosed with the Li-Fraumeni Syndrome owing to the medical and family history and also the presentation of a pathogenic mutation of the TP53 gene. There are very few case reports in the literature describing PEComa in the Li-Fraumeni syndrome, and this is the first report of a uterine PEComa in a patient with Li-Fraumeni syndrome.

A Case of Uterine Lymphangioleiomyomatosis Complicated by Tuberous Sclerosis Complex

Lymphangioleiomyomatosis (LAM) is one of the presentations of perivascular epithelioid cell neoplasm that is frequently complicated by tuberous sclerosis complex (TSC). Here, we report an uncommon case of uterine LAM treated with everolimus, which is a mechanistic target of rapamycin (mTOR) inhibitor. A 42-year-old female patient (gravida 0) with a history of TSC presented with abdominal pain. Pelvic magnetic resonance imaging showed multiple masses in the uterine myometrium, suggesting tumors that may contain internal hemorrhagic components. The lesions were suspected as the root cause of her symptoms. After everolimus was administered for a previously diagnosed renal angiolipoma, her uterine tumors temporarily decreased in size. Subsequently, laparoscopic hysterectomy and bilateral salpingectomy were performed since she could not tolerate everolimus for a long period due to the medication's side effects. Furthermore, the patient was diagnosed with LAM through histopathological examination after surgical resection. Therefore, it is advisable to suspect and investigate uterine LAM when a patient with a history of TSC presents with irregular genital bleeding or abdominal pain. Moreover, mTOR inhibitors may be a treatment option, in addition to surgery, in cases of uterine LAM exacerbation.

Perivascular epithelioid cell tumour and investigation of genetic susceptibility

A patient in her 60s was referred to be investigated for an incidental large uterus with a history of renal cell carcinoma and melanoma. Uterine biopsy revealed features of perivascular epithelioid cell tumours (PEComas) and she underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Final histology confirmed PEComa with malignant features. Genomic studies did not reveal any deleterious germline variants; however, in view of her history, she is now under a 6-month follow-up with gynaecology-oncology. PEComas are rare tumours associated with tuberous sclerosis and melanoma, sharing genetic abnormalities. Gynaecological PEComas usually present with no or non-specific symptoms. Preoperative investigations are often misleading. Final histology and immunohistochemistry have overlapping features with smooth muscle tumours. Although rare, PEComas need to be treated aggressively to minimise the potential risk of spread. There is currently little evidence about further adjuvant treatment and no clear follow-up protocol. However, the literature suggests that the prognosis is generally good.

Endometrial carcinoma with diffuse melanocytic differentiation: Clinicopathological and molecular analysis of a case with literature review and focus on differential diagnosis

Herein, we present a clinicopathological and molecular analysis of a case of endometrial carcinoma with diffuse melanocytic differentiation with literature review. A 72-year-old woman underwent hysterectomy due to a 14 cm endometrial mass. On histology, the tumor showed a serous carcinoma component and a solid component with giant eosinophilic and dyshesive multinucleated cells. Differential diagnosis included several entities, such as undifferentiated giant cell carcinoma and carcinosarcoma with rhabdomyoblasts. The solid component showed diffuse positivity for cytokeratin AE1/AE3, Melan A, Cathepsin K and S100, focal HMB45 positivity and loss of e-cadherin. The tumor was p53-abnormal, mismatch repair-proficient and POLE-wild-type. The patient had extrauterine metastases and was alive with disease at 12 months. Previous cases of endometrial and ovarian carcinomas with melanocytic differentiation (n = 7) did not show giant bizarre cells but showed melanin production; all cases were advanced and/or had unfavorable outcomes. In conclusion, endometrial carcinomas with melanocytic differentiation are highly aggressive tumors which should be distinguished from other entities. Being aware of this entity may help not to miss it.

18 F-FDG and 68 Ga-FAPI-04 in the Evaluation of Aggressive Perivascular Epithelioid Cell Tumor

ABSTRACT

A 10-year-old girl with a right renal mass underwent 18 F-FDG PET/CT and 68 Ga-FAPI-04 PET/MRI for presurgical assessment of tumor invasion and malignant potential. The mass showed low 18 F-FDG uptake and intense 68 Ga-FAPI-04 uptake. Nephrectomy was performed, and the histopathologic diagnosis was aggressive PEComa (perivascular epithelioid cell tumor). This case showed that 68 Ga-FAPI-04 PET outperformed 18 F-FDG PET in detecting aggressive PEComa.

Epithelioid Leiomyosarcoma of the Uterus: Modern Outcome-based Appraisal of Diagnostic Criteria in a Large Institutional Series

Epithelioid leiomyosarcoma of the uterus is rare and poorly understood. Herein, we characterize a large institutional series of epithelioid leiomyosarcomas aiming to define outcome-determinant diagnostic pathologic features. We also retrieved epithelioid smooth muscle tumors of unknown malignant potential and evaluated a consecutive cohort of leiomyomas for epithelioid subtypes. Of a total of 1177 uterine leiomyosarcomas, 81 (7%) were categorized as epithelioid after review. Epithelioid leiomyosarcoma was strictly defined as having round to polygonal cells with visible pink cytoplasm and round to ovoid nuclei in ≥50% of the tumor volume. Average age was 55 years (range: 26 to 81 y). Median tumor size was 11 cm; tumor was >5 cm in 93% of subjects; 47% were stage 1 at presentation. An infiltrative tumor border was observed, grossly and/or microscopically, in 89% of cases; necrosis was noted in 80%, and vascular invasion in 47%. Mitotic count in 2.4 mm2 (totalling 10 high-power fields, each field 0.55 mm in diameter) ranged from 3 to 100 (median: 26). All cases had moderate, severe or highly pleomorphic atypia. All cases had 2 or 3 of the following: necrosis, at least moderate atypia and ≥4 mitoses in 2.4 mm2. Immunohistochemistry revealed frequent expression of smooth muscle markers including SMA (96%), desmin (95%), and caldesmon (81%). HMB45 and Melan-A were negative in 92% and 100% of cases, respectively. Estrogen and progesterone receptors were expressed by 65% and 54% of tumors, respectively. Follow-up information was available in 68 subjects (median: 23 mo, range: 1 to 254); cancer-related death occurred in 63%, and an additional 15% had recurrent or metastatic disease at last follow-up. Disease-specific survival was shorter in epithelioid leiomyosarcoma patients (median: 44  mo; 35% at 5-y) than in a matched cohort of nonepithelioid leiomyosarcoma (median: 55 mo; 46% at 5-y) (P=0.03). Three epithelioid smooth muscle tumors of unknown malignant potential were evaluated, all <5 cm in size and with atypia and/or irregular borders but mitotic count below the threshold for malignancy. Two of these had follow-up available, which was uneventful. Of 142 consecutive leiomyomas assessed, none had epithelioid morphology as defined. Epithelioid leiomyosarcoma is an aggressive neoplasm, sometimes with a remarkably low mitotic count. In the setting of an epithelioid smooth muscle tumor of the uterus, we postulate that the diagnosis of malignancy is made in the presence of ≥2 of the following: moderate or severe atypia, ≥4 mitoses/2.4 mm2 and tumor cell necrosis. In their absence, the finding of tumor size ≥5 cm, vascular invasion, infiltrative edges or atypical mitoses should be treated with caution, and designation as of at least uncertain malignant potential is warranted.

TSC2-mutant uterine sarcomas with JAZF1-SUZ12 fusions demonstrate hybrid features of endometrial stromal sarcoma and PEComa and are responsive to mTOR inhibition

Uterine perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm that occasionally shares morphologic and immunohistochemical overlap with low- and high-grade endometrial stromal sarcoma (LGESS and HGESS). In this study, we sought to characterize the clinical, morphologic, genetic, and epigenetic features of five uterine sarcomas that display histologic features of LGESS, HGESS, and PEComa. All tumors demonstrated epithelioid cells often associated with a low-grade spindled component resembling LGESS, with both regions expressing CD10, ER, PR, variable HMB45, and Melan-A immunoreactivity, and strong cathepsin K and pS6 expression. Targeted massively parallel sequencing analysis revealed the presence of somatic TSC2 mutations in all five cases, of which four harbored concurrent or consecutive JAZF1-SUZ12 gene fusions. Unsupervised hierarchical clustering analysis of methylation profiles of TSC2-mutant uterine sarcomas (n = 4), LGESS (n = 10), and HGESS (n = 12) demonstrated two clusters consisting of (1) all LGESS and TSC2-mutant uterine sarcomas and (2) all HGESS. KEGG pathway analysis detected methylation differences in genes involved in PI3K/AKT, calcium, and Rap1 signaling. TSC2-mutant uterine sarcomas were responsive to hormone suppression, and mTOR inhibition demonstrated clinical benefit in four patients with these neoplasms. Our results suggest that these tumors represent histologically distinctive LGESS with TSC2 mutations. TSC2 mutations and JAZF1-SUZ12 fusion may help diagnose these tumors and possibly direct effective treatment.

Cervical Angiomyolipoma Coexisting with Endometrial Carcinoma in the Absence of Tuberous Sclerosis: A Rare Case Report

Angiomyolipoma (AML) is a rare benign mesenchymal neoplasm composed of variable admixture of blood vessels, smooth muscle, and adipose tissue; most commonly located in kidney, and is usually associated with tuberous sclerosis. Extrarenal AML has been reported in various sites, although infrequently in female genital tract (FGT). AML in cervix is extremely rare and only six cases have been reported so far. A 46-year-old postmenopausal female presented with lower abdominal pain, bleeding for 4 days and a polypoidal mass protruding through the cervical os. Endometrial curettings were suggestive of endometrial adenocarcinoma—endometrioid type (World Health Organization [WHO]). The subsequent hysterectomy specimen confirmed the diagnosis and the histologic grade was International Federation of Obstetrics and Gynecology (FIGO) grade I and stage was pT1aN0 (American Joint Committee on Cancer [AJCC], 8th edition). Cervical polyp showed AML. CD34 and smooth muscle actin (SMA) showed diffuse positivity in blood vessels and smooth muscle cells, respectively. HMB-45 was negative. This is the first ever reported case of AML coexisting with endometrial carcinoma in the absence of tuberous sclerosis. CD34 is a good marker for delineating the blood vessels and SMA for both the smooth muscle and vascular components. S100 is generally not needed to prove the adipose tissue component. HMB-45 is not consistently expressed in AML of female genital tract.

Malignant uterine perivascular epithelioid cell tumor: histopathologic and immunohistochemical characterization of a rare tumor in a post-menopausal woman

BACKGROUND

Perivascular epithelioid cell tumors (PEComas) are rare, mesenchymal neoplasms composed of epithelioid cells exhibiting myogenic and melanocytic differentiation. The uterus is an infrequent site of involvement. The most common histopathologic mimics include leiomyosarcoma, endometrial stromal sarcoma, undifferentiated uterine sarcoma, and malignant melanoma. Rendering an accurate histopathologic diagnosis is essential, owing to the prognostic and therapeutic implications.

CASE

A 65-years-old post-menopausal woman presented with post-menopausal bleeding, abdominal pain, and heaviness for the last four months. Ultrasound abdomen revealed a large uterine mass replacing the endometrial cavity. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy.

RESULT

Microscopically, a circumscribed tumor with tumor cells arranged in sheets and interlacing fascicles, with interspersed fine capillary network, was seen. The individual tumor cells were epithelioid to spindle with moderate pleomorphism, round nuclei, vesicular chromatin, prominent macronucleoli, and moderate cytoplasm. Mitosis was 2-3/50 HPFs. On immunohistochemistry, tumor cells were positive for HMB-45, Melan-A, and smooth muscle actin and were negative for h-caldesmon, TFE3, S-100, CD10, and pan-cytokeratin. Based on the histopathologic and immunohistochemical features, a final diagnosis of malignant uterine PEComa was rendered.

CONCLUSIONS

This index report describes the characteristic histopathologic and immunohistochemical features of malignant uterine PEComa and highlights the salient features that distinguish it from other commonly encountered histopathologic mimics.

Sustained response to pembrolizumab in recurrent perivascular epithelioid cell tumor with elevated expression of programmed death ligand: a case report

Background

Perivascular epithelioid cell tumors are defined by the World Health Organization as “a collection of rare mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells.” Whereas localized perivascular epithelioid cell tumor is typically benign and treated successfully with surgical resection, prognosis for patients with advanced or metastatic perivascular epithelioid cell tumor is unfavorable, and there is no standard curative treatment.

Case presentation

We report a Caucasian case of metastatic perivascular epithelioid cell tumor previously treated with chemotherapy and surgery with elevated surface expression of programmed cell death ligand 1. Based on this result, treatment via immune checkpoint inhibition with the monoclonal antibody pembrolizumab was pursued. After 21 cycles, the patient sustained a complete response. Therapy was stopped after the 40th cycle, and she was moved to surveillance. She remained disease free 19 months off treatment.

Conclusions

This case report of a patient with perivascular epithelioid cell tumor treated successfully with programmed cell death protein-1 targeted therapy suggests that programmed cell death ligand-1 levels should be measured in patients with perivascular epithelioid cell tumor and immunotherapy considered for recurrent or metastatic patients. Future phase II/III studies in this disease should focus on sequencing of surgery and immunotherapy with a design of curative intent.

Gynaecological perivascular epithelioid cell tumour (PEComa): comparative analysis of proposed algorithms for prediction of clinical outcome

AIMS

Perivascular epithelioid cell tumours (PEComas) are rare mesenchymal tumours that coexpress smooth muscle and melanocytic markers. They have a predilection for gynaecological organs, where they present a unique diagnostic challenge, because of morphological and immunohistochemical overlap with more common smooth muscle and stromal tumours. Limited information regarding the natural history, owing to the rarity of this tumour, makes accurate risk stratification difficult. We aimed to review clinicopathological features of gynaecological PEComa and compare accuracy of five different classification systems for prediction of prognosis.

METHODS AND RESULTS

We have described the clinicopathological features of 13 new cases and tested five prognostic algorithms in a total of 67 cases of gynaecological PEComa. Receiver operating characteristic curves were constructed and areas under the curve (AUCs) were calculated to evaluate predictive accuracy. The modified gynaecological-specific algorithm showed high sensitivity and specificity and yielded the highest AUC (0.864). It's earlier version, the gynaecological-specific algorithm, suffered from lower specificity (AUC = 0.843). The post-hoc McNemar test confirmed significant differences between the performances of the modified gynaecological-specific algorithm and the gynaecological-specific algorithm (P = 0.008). The original Folpe algorithm for PEComas of all sites showed low specificity, had a lower AUC (0.591), and was inapplicable in 18% of cases. Its two later versions (the revised Folpe algorithm and the modified Folpe algorithm) also yielded lower AUCs (0.690 and 0.591, respectively).

CONCLUSION

We have shown that the modified gynaecological-specific algorithm predicts the clinical outcome of gynaecological PEComa with high accuracy, and have validated its use for prognostic stratification of gynaecological PEComa.

PNL2: A Useful Adjunct Biomarker to HMB45 in the Diagnosis of Uterine Perivascular Epithelioid Cell Tumor (PEComa)

Perivascular epithelioid cell tumors (PEComa) are rare neoplasms characterized by co-expression of melanocytic and muscle markers. HMB45 and Melan-A are used to confirm a PEComa diagnosis; however, both are often focally expressed and sensitivity for Melan-A is low. PNL2 is a reliable biomarker for epithelioid melanoma and renal angiomyolipoma/PEComa. The objective of this study was to determine PNL2 utility in diagnosing uterine PEComas as well as distinguishing PEComas from uterine smooth muscle tumors (SMTs). Twenty-one uterine PEComas and 45 SMTs were analyzed for PNL2; a subset was also stained for HMB45, Melan-A, Cathepsin-K, Desmin, and h-Caldesmon. Cases were scored as negative (0), focal (<10% of tumor cells), or patchy to diffusely positive (>10% of tumor cells). PEComas were positive for PNL2, HMB45, and Melan-A in 86%, 100%, and 57% of cases, respectively. In PEComas, PNL2 was patchy to diffusely positive more frequently (10/18, 56%) than Melan-A (4/12, 33%). In contrast, 2 of 45 (4%) SMTs were focally PNL2 positive; HMB45 was focally positive in 4 SMTs (11%) and all were negative for Melan-A. Desmin and h-Caldesmon were positive in 90% and 57% of PEComas, and 91% and 82% of SMTs. Cathepsin-K was positive in 100% of PEComas and 93% of SMTs. PNL2 is a useful biomarker for the diagnosis of uterine PEComa, with comparable sensitivity and specificity to HMB45. In contrast, PNL2 stains more PEComas when compared with Melan-A. Cathepsin-K, Desmin, and h-Caldesmon are of little utility for distinguishing PEComas and SMTs; however, lack of Cathepsin-K argues against PEComa. These results suggest that PNL2 should be used in conjunction with HMB45 in the diagnosis of PEComa of the uterine corpus.

VEGFR Inhibitors for Uterine Metastatic Perivascular Epithelioid Tumors (PEComa) Resistant to mTOR Inhibitors. A Case Report and Review of Literature

Uterine perivascular epithelioid cell tumors (PEComas) are rare neoplasms. PI3K/AKT/mTOR pathway upregulation is critical for their pathogenesis and is often associated with TSC1/TSC2 inactivation. Although first line mTOR inhibitors are an effective treatment, metastatic PEComas eventually progress. A 53-year-old woman presented a 4-month history of post-menopausal vaginal bleeding. Clinical and radiological examination detected a uterine mass and a single S1 bone lesion. The patient underwent a radical hysterectomy and bone biopsy. The anatomopathological evaluation concluded to an oligo-metastatic uterine PEComa. The tumor harbored a heterozygous deletion of 9q34 that contains the TSC1 gene. Concerning the primary lesion, the resection was complete and the single bone metastasis was treated with radiotherapy. Three months later, the patient presented bone, lung and subcutaneous metastatic progression. An everolimus and denosumab treatment was initiated. After 2 years of treatment, a clinically significant bone, lung and subcutaneous progression was detected. Following a literature review of the possible therapeutic options, we initiated a second line treatment by pazopanib. This treatment resulted in regression of the subcutaneous lesions and stability of lung and bone metastases. In this challenging, rare setting, our report suggests single agent, anti-angiogenic, tyrosine kinase inhibitor to be effective as second line treatment of metastatic uterine PEComa progressing on mTOR inhibitors.

Uterine angiomyolipoma: a clinical analysis of 8 cases and literature review

PURPOSE

Uterine angiomyolipoma (AML) is a rare condition involving benign tumors composed of varying proportions of blood vessels, fat, and epithelioid or spindled smooth muscle cells. We analyzed the clinicopathological features, diagnosis and treatment methods, and prognosis of uterine AML.

METHODS

We retrospectively analyzed the clinical-pathological data of eight patients with pathologically diagnosed uterine AML at a single center from January 2008 to July 2020.

RESULTS

The mean age of the patients was 50 years (range, 41-62). One patient was asymptomatic; the main clinical manifestations of the others included vaginal bleeding (3), menorrhagia (2), abdominal pain (1), and dysmenorrhea with adenomyosis (1). In one case, fat components observed via abdominal computed tomography led to a diagnosis of uterine leiomyolipoma; the rest were diagnosed as uterine leiomyoma (4), uterine fibroid degeneration (2), and pelvic mass (1). The lesions were in the body of the uterus (6), the fundus of the uterus (1), and the broad ligament (1). Seven patients had a focal soft tumor texture, and one had a tough texture; the lesions were yellow (3), yellow-white (3), and pinkish white (2). Surgeries included transabdominal myomectomy (2), transabdominal hysterectomy (2), transabdominal hysterectomy/bilateral salpingo-oophorectomy (2), and laparoscopic total hysterectomy/bilateral salpingectomy (2). The median follow-up time was 72 months. No relapses were reported.

CONCLUSION

Uterine AML has a low incidence rate and is most likely to occur in perimenopausal women. The clinical manifestations are similar to those of uterine leiomyomas, but AML should be suspected if the internal echo of the uterine tumor is uneven and contains adipose tissue.

Uterine plexiform tumourlets: multifocal and solitary cases with subsets expressing melanocytic markers

AIMS

Uterine plexiform tumourlets are traditionally regarded as microscopic epithelioid leiomyomas. They are typically solitary incidental findings, but may be multifocal (plexiform leiomyomatosis). We aim to report novel immunohistochemical and morphological findings, specifically the presence of spindled and epithelioid cell nodules, in these lesions.

METHODS AND RESULTS

Three cases of plexiform leiomyomatosis and 16 solitary plexiform tumourlets were included. Two cases of plexiform leiomyomatosis and four solitary plexiform tumourlets demonstrated spindled and epithelioid cell nodules which, in one of the former cases, formed expansile masses up to 15 mm. The nodules demonstrated mild cytological atypia and occasional mitotic activity, and they were associated with a myxoid stroma and a lymphohistiocytic infiltrate which imparted a granulomatous appearance to the microscopic lesions. The plexiform tumourlets (solitary and multifocal) consistently expressed desmin, smooth muscle actin, ER and PR, and they commonly co-expressed melanocytic and perivascular epithelioid cell (PEC) markers HMB45, MiTF and cathepsin K. The spindled and epithelioid cell nodules were generally negative for myoid markers and hormone receptors, but expressed p16, cyclin D1 and TFE3. All lesions tested were negative for cytokeratin, S100, melanA, inhibin, EMA, ALK and BCOR; fluorescence in-situ hybridisation was negative for ALK, TFE3 and BCOR rearrangements in one of the larger spindled and epithelioid cell nodules.

CONCLUSIONS

Plexiform tumourlets commonly co-express myoid and melanocytic markers and may represent part of the spectrum of gynaecological PEC-related lesions. Some cases are associated with spindled and epithelioid cell nodules that could potentially mimic other uterine myxoid neoplasms.

Perivascular epithelioid cell tumors (PEComa) of the gynecologic tract

PEComas of the female genital tract are rare mesenchymal neoplasms that are most common in the uterus, but also may occur in other gynecologic locations. As they morphologically and immunohistochemically resemble smooth muscle tumors, distinction between the two entities is often challenging, and may be aided by molecular analysis. Thus far, two distinct molecular groups-classic PEComas with TSC mutations and TFE3-translocation associated PEComas with TFE3 fusions have been described. Recognition of the first group is imperative as these patients may benefit from targeted therapy with mTOR inhibitors, if malignant. This review will focus on recognition of the morphologic and immunophenotypic features of PEComas, as well as the role of molecular testing in their diagnosis and treatment, analysis of the different algorithms to predict behavior, and differential diagnosis.

Perivascular epithelioid cell tumors (PEComa) of the female genital tract: A challenging question for gynaecologic oncologist and pathologist

Perivascular epithelioid cell tumors (PEComa)s are mesenchymal neoplasms composed of perivascular epithelioid cells, which express both melanocytic and myogenic markers. These neoplastic cells are thought to arise from undifferentiated cells of the neural crest, or from myoblastic cells harbouring a molecular alteration leading to expression of melanocytic markers, or from pericytic cells. The majority of cases are benign, but a small subset behaves in a malignant fashion. Unfortunately, given their rarity, reliable criteria for predicting malignancy have yet to be established. PEComas of the female genital tract account for nearly 25% of PEComas of all body sites, and the most common site of occurrence is the uterine corpus; less common sites include the cervix, adnexa, vagina/vulva or broad or round ligament exceptionally. The present review aims to elucidate the clinical, pathological and molecular features of gynecological PEComas. Moreover, prognostic and therapeutic implications are also discussed.

SMARCA4-deficient uterine sarcoma: A case report and a concise review

Background

SMARCA4-deficient uterine sarcoma (SDUS) is a newly discovered undifferentiated uterine mesenchymal malignancy which has loss of expression of SMARCA4.

Case

A 46-year-old woman presented with heavy irregular vaginal bleeding over the previous 5 months. Computed tomography and magnetic resonance imaging showed a large pelvic mass centered within the uterus, suspicious of malignancy with regional metastatic lymphadenopathy. Biopsy confirmed SDUS and patient underwent chemotherapy. Her symptoms improved 3 months after treatment.

Conclusion

An extremely rare case of this newly described entity is reported. Recognizing the characteristic imaging and pathology findings of SDUS is essential for an accurate diagnosis, which may affect patient survival.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Endometrial polyp-like perivascular epithelioid cell neoplasm associated with TFE3 translocation: report of one case

This article reports the pathologic features and malignant biological behavior of a perivascular epithelioid cell neoplasm (PEComa) with the clinical manifestation being endometrial polyps. The case was cured with curettage in a local hospital one year ago. The postoperative diagnosis was "endometrial polyps". This time, due to "irregular bleeding", we carried out another curettage in our hospital. After the operation, 3 pieces of polyps were inspected with diameters of 0.3 cm, 0.5 cm and 0.6 cm, respectively. The tumor consisted of epithelioid cells with alveolar and nesting pattern and showed a diffuse strong expression of HMB45, Melan-A and TFE3. The patient then underwent a hysterectomy and the "polyps" were sent for pathological examination. The result showed that tumor cells infiltrated the deep muscle layer, close to the outer membrane, suggesting a malignant biologic behavior. TFE3-related PEComa is different from general PEComa. This neoplasm and Melanotic Xp11 renal carcinoma have similar clinicopathologic features, histology, immunity and molecular phenotypes, belonging to the same type of tumor. It has been suggested in the literature naming this neoplasm as 'Xp11 neoplasm with melanocytic differentiation' or 'melanotic Xp11 neoplasm'. Our case has expanded our understanding of PEComa characteristics and increased data for TFE3 translocation-related PEComa, reminding us to avoid misdiagnosis when PEComa manifests as small polyps.

Surprise Lymph Node Histology in a Patient with Ovarian Serous Carcinoma

We report a case of a sixty-three-year-old Chinese female with a known past history of primary, biopsy-diagnosed, ovarian high-grade serous carcinoma. Following three cycles of chemotherapy, she underwent total hysterectomy, bilateral salpingo-oophorectomy cytoreductive surgery with lymphadenectomy, and multiple peritoneal biopsies. In this situation, the lymph nodes would be expected to demonstrate possible residual metastatic serous carcinoma with or without chemotherapy effect. The final diagnostic assessment in the lymph nodes, in this patient, however, was a rare combination of the following pathologies: metastatic serous carcinoma, with areas of chemotherapy effect, and incidental PEComatosis, focally in association with endometriosis, both within lymph nodes and surrounding connective tissue. PEComas have been described in patients with the tuberous sclerosis complex, but the current patient was not known to suffer from this condition. This case is also unusual, as although PEComas have been described as arising in the female genital tract, the associated phenomenon of endometriosis is exceedingly rare, and this is the first known reported case of lymph nodes harbouring a similar combination of pathologies.

Malignant Pleural PEComa: A Previously Undocumented Site

Perivascular epithelioid cell (PEC) tumors are rare tumors of mesenchymal origin and can affect many anatomic regions. Although these tumors are usually benign, malignant variants exist. We document for the first time a malignant PEComa arising from the pleura of a 43-year-old Malay woman. The pathology of the tumor as well as differential diagnoses is discussed.

Uterine Mesenchymal Tumors: Update on Classification, Staging, and Molecular Features

The spectrum of mesenchymal neoplasia in the uterus has expanded in recent years. First, the identification of prevalent, recurrent molecular alterations has led to a more biologically and clinically congruent classification of endometrial stromal tumors. Likewise, the diagnostic criteria of several rare and miscellaneous tumor types have been refined in recent case series (Perivascular Epithelioid Cell tumor, inflammatory myofibroblastic tumor). Pure mesenchymal tumors are still broadly classified based on morphology according to the tumor cell phenotype. Smooth muscle tumors predominate in frequency, followed by tumors of endometrial stromal derivation; the latter are covered in depth in this article with an emphasis on defining molecular alterations and their morphologic and clinical correlates. The remaining entities comprise a miscellaneous group in which cell derivation does not have a normal counterpart in the uterus (eg, rhabdomyosarcoma) or is obscure (eg, undifferentiated uterine sarcoma). This article discusses their clinical relevance, recent insights into their molecular biology, and the most important differential diagnoses. Regarding the latter, immunohistochemistry and (increasingly) molecular diagnostics play a role in the diagnostic workup. We conclude with a few considerations on intraoperative consultation and macroscopic examination, as well as pathologic staging and grading of uterine sarcomas as per the most recent American Joint Cancer Commission and the Fédération Internationale de Gynécologie et d'Obstétrique staging systems.

Isolated sporadic uterine lymphangioleiomyoma with unusual clinical and pathological features

We report a unique uterine neoplasm, favoured to represent an isolated extrapulmonary lymphangioleiomyoma with unusual pathological features, in a postmenopausal woman without tuberous sclerosis complex. The large neoplasm consisted of smooth muscle fascicles and cystic spaces lined by lymphatic cells, which were negative for the melanocytic staining that is characteristically positive in lymphangioleiomyomatosis (LAM). There are fewer than 30 cases of uterine LAM reported, none of which have demonstrated this morphology or these immunohistochemical findings. The origin of LAM cells in the more typical pulmonary LAM remains unclear; the unusual features in this case may represent a distinct pathological entity or a rare variant of typical extrapulmonary LAM, and may contribute to determining the cellular origin of these rare tumours. Conversely, this may represent a case of 'prepulmonary' LAM, providing supporting evidence for a possible gynaecological origin of these tumours in the broader affected (almost exclusively female) population.

An unusual case of uterine PEComa presenting with disseminated intravascular coagulation

Perivascular epithelioid cell neoplasms (PEComas) are mesenchymal neoplasms originating from the perivascular epithelioid cell (PEC) line. The World Health Organization (WHO) further defines PEComa as “a mesenchymal tumor composed of histologically and immunohistochemically distinctive perivascular epithelioid cells”. Gynecologic PEComas account for approximately ¼ of the PEComa cases reported in the literature and are histologically characterized by stromal hyalinization with complete or partial circumscription with hyaline background and diffuse, small vessel vascularity (Musella et al., 2015). Uterine PEComas typically present with vaginal bleeding and/or a uterine mass, are managed surgically with resection, and can be followed by adjuvant treatment if indicated based on pathologic risk factors for aggression. Adjuvant therapy is not standardized given the rarity of these tumors, and can include chemotherapy, radiation, targeted therapy (mTOR inhibitors due to common gene mutations and a hypothesized pathophysiology of this neoplasm) and/or hormones. In this case report, we describe an unusual presentation for a uterine PEComa in a woman initially complaining of worsening cutaneous bruising and petechiae, found to be in florid disseminated intravascular coagulation (DIC) without a clear etiology. Ultimately her extensive hematology evaluation only found a large uterine mass that appeared to be a 9 cm fibroid. She underwent hysterectomy following recovery from her DIC, and was diagnosed with a large uterine PEComa.

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PEComas are mesenchymal perivascular epithelioid cell (PEC) neoplasms.

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Disseminated intravascular coagulation (DIC) has been reported in solid tumors.

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DIC is mediated in solid tumors by the generation of tissue factor.

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Primary treatment for PEComa is excision.

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Postoperatively, treatment for PEComa can be with targeted medical therapy.

Extrapulmonary uterine lymphangioleiomyomatosis (LAM) and dysfunctional uterine bleeding: the first presentation of LAM in a tuberous sclerosis complex patient

Lymphangioleiomyomatosis (LAM) is a rare disease that typically affects women of childbearing age. It most commonly affects the lungs (P-LAM) but can occasionally occur in extra-pulmonary sites (E-LAM). There is a strong association between LAM and the tuberous sclerosis complex (TSC). We report a case of a 42-year-old female TSC sufferer who presented with dysfunctional uterine bleeding. She was not known to have LAM. An endometrial biopsy revealed a spindled-cell lesion suspicious of leiomyosarcoma, which correlated with cross-sectional imaging. She underwent a hysterectomy that showed a bizarre (symplastic) leiomyomatous endometrial polyp with background uterine LAM. We discuss the clinical and pathological implications of this unusual case of E-LAM and the importance of clinicopathological correlation in TSC sufferers. The association of uterine LAM with TSC is important and LAM should be considered as a differential of dysfunctional uterine bleeding and a benign mimic to uterine leiomyosarcoma in patients with TSC.

Malignant perivascular epithelioid cell tumor in the female genital tract: Preferred reporting items for systematic reviews and meta-analyses

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor, located at various anatomic sites, including the female genital tract. This study aimed to evaluate the clinicopathological characteristics of patients with PEComa arising from the female genital tract.

METHODS

A retrospective study was conducted in Taipei Veterans General Hospital (Taipei VGH) between 2008 and 2018. All published English cases based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement were also included in the current review.

RESULTS

A total of 114 women from PRISMA and 3 women from Taipei VGH were identified. The uterus was the most commonly involved site (82/114, 71.9%), followed by the cervix (12/114, 10.5%). Immunohistochemical staining showed that nearly all gynecological PEComas were positive for human melanoma black 45 (113/114, 99.1%). More than half of the gynecological PEComas were immunoreactive for desmin (50/85, 58.8%). Multi-modality treatment, including surgery and mammalian target of rapamycin (mTOR) inhibitors as targeted therapy, provided long-term disease-free survival (cure rate ranging from 50% to 100%, based on the different anatomic sites of the female genital tract).

CONCLUSION

Multi-modality treatment, including cytoreductive surgery and mTOR inhibitors with/without chemotherapy and/or radiation, should be considered for the management of women with PEComas in the genital tract.

Five cases of uterine perivascular epithelioid cell tumors (PEComas) and review of literature

OBJECTIVES

Perivascular epithelioid cell tumor (PEComa) is a rare condition and the recognition of this condition is limited. Here we report five cases of uterine PEComa to add to the limited understanding of this rare condition.

METHODS

Five cases from Obstetrics and Gynecology Hospital of Fudan University were diagnosed as uterine PEComas. We collected the patients' clinical and pathological data as well as their outcomes.

RESULTS

All the five cases were diagnosed post-operationally. Fertility-sparing surgery was done for the first case and had a mass resection only. She delivered a healthy boy through the cesarean section in November 2016 and neither recurrence nor metastasis was found for 71 months. Hysterectomy was done for the other four cases. Adjuvant chemotherapy was also given for case 2 and case 4. Case 2 had combined endometrial cancer, which could be associated with tuberous sclerosis complex (TSC). She was followed up for 22 months and neither recurrence nor metastasis was detected. Neither recurrence nor metastasis was found in case 3 for 33 months. However, the patient in case 4 died of multiple dissemination and multiple organs failures, 10 months after the second surgery. The patient in case 5 had the hysterectomy and left adnexal resection and in this case we had no data about her long-term outcomes.

CONCLUSION

It is still challenging to detect and diagnose uterine PEComa clinically and no consensus or guidelines have been established regarding the treatment of this condition. More case studies are needed to enlighten the underlying mechanism and help optimize the therapies for this condition.

SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma

Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

An Inguinal Perivascular Epithelioid Cell Tumor Metastatic to the Orbit

Malignant PEComas are rare mesenchymal neoplasms. These tumors harbor distinct myomelanocytic phenotype. The PEComa family of tumors includes lymphangioleiomyomatosis, angiomyolipoma, clear cell sugar tumor of the lung, and myomelanocytic tumor of the falciparum ligament/ligamentum teres. PEComas have no known normal cell counterpart. Majority of PEComas are benign and occur predominantly in the middle-age women. These tumors are commonly encountered in the uterus. Herein, we report a 20-year-old woman with a left inguinal mass metastatic to orbit, brain, lumbar spine, and skin at presentation. To our knowledge, this is the first case of metastatic PEComa to the orbit. This is the third case of primary PEComa of the inguinal area.

Primary Ovarian Malignant PEComa: A Case Report

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm characterized by expression of both melanocytic and smooth muscle markers. PEComas are rarely encountered in the female genital tract. We report a case of malignant primary PEComa of the ovary, and discuss the differential diagnosis. This represents the first case of primary typical malignant PEComa of the ovary.