PEC-PRO: A new prognostic score from a series of 87 patients with localized perivascular epithelioid cell neoplasms (PEComas) treated with curative intent.

BACKGROUND: Perivascular epithelioid cell neoplasms (PEComas) encompass a heterogeneous family of mesenchymal tumors. Previously described clinicopathologic features aimed at distinguishing benign from malignant variants but lacked prognostic value. METHODS: This retrospective analysis examined clinicopathologic data from patients who had localized PEComa across French Sarcoma Network centers. The authors analyzed 12 clinicopathologic features in a Cox proportional hazard framework to derive a multivariate prognostic risk model for event-free survival (EFS). They built the PEComa prognostic score (PEC-PRO), in which scores ranged from 0 to 5, based on the coefficients of the multivariate model. Three groups were identified: low risk (score = 0), intermediate risk (score = 1), and high risk (score ≥ 2). RESULTS: Analyzing 87 patients who had a median 46-month follow-up (interquartile range, 20-74 months), the median EFS was 96.5 months (95% confidence interval [CI], 47.1 months to not applicable), with 2-year and 5-year EFS rates of 64.7% and 58%, respectively. The median overall survival was unreached, with 2-year and 5-year overall survival rates of 82.3% and 69.3%, respectively. The simplified Folpe classification did not correlate with EFS. Multivariate analysis identified three factors affecting EFS: positive surgical margins (hazard ratio [HR], 5.17; 95% CI, 1.65-16.24; p = .008), necrosis (HR, 3.94; 95% CI, 1.16-13.43; p = .030), and male sex (HR, 3.13; 95% CI, 1.19-8.27; p = 0.023). Four variables were retained in the prognostic model. Patients with low-risk PEC-PRO scores had a 2-year EFS rate of 93.7% (95% CI, 83.8%-100.0%), those with intermediate-risk PEC-PRO scores had a 2-year EFS rate of 67.4% (95% CI, 53.9%-80.9%), and those with high-risk PEC-PRO scores had a 2-year EFS rate of 2.3% (95% CI, 0.0%-18.3%). CONCLUSIONS: The PEC-PRO score reliably predicts the risk of postoperative recurrence in patients with localized PEComa. It has the potential to improve follow-up strategies but requires validation in a prospective trial.

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.

Malignant Pigmented Epithelioid Angiomyolipoma of the Kidney in a Child with Tuberous Sclerosis Complex.

INTRODUCTION: Pigmented epithelioid angiomyolipoma is a variant of epithelioid angiomyolipoma (EAML) that has not previously been described in children with tuberous sclerosis. CASE PRESENTATION: A 15-year-old boy with tuberous sclerosis had a rapidly enlarging renal mass associated with a left lung nodule. Microscopically it was a pigmented EAML, confirmed by immunohistochemistry. DISCUSSION/CONCLUSION: The pigmented variant of EAML can arise and metastasize from the kidney of a teenager with tuberous sclerosis.

Soft Tissue Perivascular Epithelioid Cell Tumour: An Unusual Finding.

Perivascular epithelioid cell tumour (PEComa) is a rare mesenchymal tumour made up of clear perivascular cells with epithelioid characteristics, which co-expresses muscle and melanocytic markers with a component of spindle cells, like sarcoma and variety of other tissues. This time, we present the case of a young patient with a tumour in the dorsal region of progressive growth, compatible with PEComa of soft tissue after histopathological and immunohistochemical analysis.

Cutaneous "fibroma-like" perivascular epithelioid cell tumor: A case report and review of literature.

Perivascular epithelioid cell tumors (PEComas) are a group of lesions sharing the common features of co-expression of melanocytic and myogenic markers, with focal association of the cells with vascular walls. The PEComa group exhibits a wide range of morphologies. A "fibroma-like" variant of PEComa has been recently described. The case reported herein is that of an infant with tuberous sclerosis complex (TSC) presenting with a lip mass. Excisional biopsy showed a moderately cellular tumor composed of spindled to stellate cells embedded within a collagenized stroma. The cells showed focal perivascular accumulation and positivity for both melanocytic (HMB-45) and myogenic (desmin) markers. This is the fifth reported case of "fibroma-like" PEComa in literature and the youngest patient to date. All of the "fibroma-like" PEComas were found in patients with tuberous sclerosis-hence, the diagnosis of this entity should prompt a workup for TSC; conversely, a fibroma-like lesion in a patient with TSC or with TSC-related conditions should be evaluated using melanocytic and myogenic markers. Melanocytic and myogenic markers are also useful in differentiating "fibroma-like" PEComa from other differential diagnoses such as fibroma and benign fibrous histiocytoma.

Complexity of PEComas : Diagnostic approach, molecular background, clinical management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[A suspected carcinoma finding in the uterus]. / Karzinomverdächtiger Herdbefund im Uterus.

Epithelioid tumor cells of a uterine perivascular epithelioid cell tumor (PEComa) may mimic carcinoma cells in an endometrial sampling (pitfall). Immunohistochemistry (HMB45 positive, keratin negative) helps in the differential diagnosis.

[Complexity of PEComas : Diagnostic approach, molecular background, clinical management (German version)]. / Komplexität von PEComen : Diagnose, Molekulargenetik, klinisches Management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[TNM classification of gynecologic malignancies : What remains to be done beyond 2017?] / TNM-Klassifikation gynäkologischer Tumoren : Was bleibt über 2017 hinaus zu tun?

For some gynecologic malignancies, there are disagreements between the most recent WHO and TNM classifications and the recommendations of the International Collaboration of Cancer Reporting. These discrepancies are addressed and discussed in this paper. The WHO definition for primary vaginal cancer does not match the TNM definition. The paper also discusses and provides TNM classifications for rare gynecologic tumors like primary malignant vulvar melanomas, sarcomas of the vulva, perivascular epithelioid cell tumor (PECom) of the uterus, undifferentiated uterine sarcomas, and extra-intestinal gastrointestinal stromal tumors (GIST), and provides some recommendations for the reporting and categorization of regional lymph nodes in nonuterine serous pelvic cancer.

[Solitary fibrous tumor/hemangiopericytoma of central nervous system: a clinicopathological analysis of 60 cases].

Objective: To investigate the clinical manifestations, imaging features, clinicopathologic features, and differential diagnosis of solitary fibrous tumors/anginoblastomas (SFT/HPCs) originating in the central nervous system. Methods: Sixty cases of SFT/HPCs originating in the central nervous system were collected at Nanjing Jinling Hospital, from January 1, 2008 to December 31, 2016. The clinical data, imaging data, histomorphologic changes and immunohistochemical finding were analyzed in the sixty cases. Results: The 60 cases included 26 males and 34 females, aged 14 to 85 (median 49) years. The main clinical manifestations were headache, dizziness with nausea and vomiting. Radiologically, the tumors were large, enhancing, solid and cystic masses attached to the dura. Histopathologically, the neoplasms were composed of spindle cells with oval nuclei, inconspicuous nucleoli and moderate amount of eosinophilic cytoplasm arranged in fascicles with areas of hyalinized stroma, myxoid changes and a staghorn vascular pattern. Immunohistochemically, tumor cells of all cases were positive for vimentin (100.0%, 60/60), STAT6 (98.3%, 59/60), CD34 (61.7%, 37/60), and the tumor cells were typically positive for CD99, bcl-2, EMA and SSTR2 as well.Negative for S-100 protein, SOX10, E-cadherin, GFAP. Ki-67 index ranged from 1% to 50%. Forty cases were followed up for 6 to 82 months with average of 40 months, 30 patients were alive and 10 patients died. Conclusions: Central nervous system SFT/HPCs can be aggressive and relapses may occur several years after diagnosis. STAT6 is highly sensitive and specific for the diagnosis. Complete tumor resection is optional treatment followed by radiotherapy and chemotherapy. There is a correlation between the prognosis and the location of the disease, the histological grade, Ki-67 index, and fusion gene variants.

[Clinical analysis of hepatic perivascular epithelioid cell neoplasm: a report of eleven cases].

Objective: To investigate the clinical features, diagnosis and therapy of hepatic perivascular epithelioid neoplasms (PEComa). Methods: The clinical data of eleven patients with hepatic PEComa who received surgical treatment at Shengjing Hospital Affiliated to China Medical University from April 2012 to October 2017 were collected. The clinical manifestations, imaging features, diagnostic and therapeutic strategies, pathologic features, prognosis were analyzed. Results: The patients aged from 35 to 55 years (mean: 47 years , 3 males and 8 females). Two patients had epigastric pain, the others rarely had any clinical symptom. Hepatitis C virus (HCV) infection was present in one patient 9.09%(1/11), the rate of correct diagnosis by imageological examination before operation was only 9.09%(1/11). All patients received a surgical resection, the final diagnosis of hepatic PEComa was made with pathology and immunohistochemistry. The antibodies used for immunohistochemistry varied from patient to patient. The positive rates of Melan A, HMB45, smooth muscle actin and S-100 were 100%(10/10), 90%(9/10), 77.8%(7/9)and 33.3%(3/9) respectively, the Ki-67 positive index was 1%-10%. One patient died after surgery because of hemorrhage, other ten patients received long-term follow-up(5-71 months), and no recurrence or metastasis was observed. Conclusion: Hepatic PEComa is a rare mesenchymal neoplasm which expresses both melanocytic and myogenic markers. Middle aged females are susceptive to hepatic PEComa, and patients rarely have any specific clinical presentation. It's difficult to make a correct diagnosis before operation. The diagnosis finally depends on the pathological examination. Surgical resection and close follow-up are the principal methods for the management of hepatic PEComa.

Comprehensive Insights Into Renal Perivascular Epithelioid Cell Neoplasms: From Molecular Mechanisms to Clinical Practice.

Perivascular epithelioid cell neoplasms (PEComas) are a rare category of mesenchymal tissue tumors, manifesting across various tissues and organs such as the kidneys, liver, lungs, pancreas, uterus, ovaries, and gastrointestinal tract. They predominantly affect females more than males. PEComas characteristically express both melanocytic and smooth muscle markers, making immunohistochemistry vital for their diagnosis. Renal angiomyolipoma (AML) represents a common variant of PEComas, typically marked by favorable prognoses. Nonetheless, only a small fraction of subtypes, especially epithelioid AML, possess the capacity to be malignant. Renal PEComas usually appear as asymptomatic masses accompanied by vague imaging characteristics. The main methods for diagnosis are histopathological analysis and the application of immunohistochemical stains. Presently, a uniform treatment plan for renal PEComas is absent. Strategies for management include active surveillance, selective arterial embolization, surgical procedures, and drug-based treatments. The focus of this review is on renal PEComas, shedding light on their pathogenesis, pathological characteristics, clinical presentations, diagnosis, and treatment modalities, and incorporating a clinical case study.

Clear cell myomelanocytic tumor of ligamentum teres.

Clear cell myomelanocytic tumor (CCMMT) of the falciform ligament/ligamentum teres is a rare hepatic tumor, a variant of the perivascular epithelioid cell tumor (PEComa) family. CCMMT is the rarest variant of hepatic PEComas. Only a few cases of CCMMT have been reported in the English literature. Because of its rarity, less is known about its biological behavior. We present a case of a 31-year-old female who complained of abdominal pain, bilious vomiting, and abdominal fullness over two months. The radiological impression was of focal nodular hyperplasia. The histological examination of the resection specimen revealed a well-circumscribed tumor arranged in fascicles, sheets, and a whorling pattern. The tumor cells were spindle to epithelioid shaped with abundant clear to pale eosinophilic cytoplasm. The tumor cells expressed both myoid (smooth muscle actin) and melanocytic (MelanA and HMB45) markers, while they were negative for hepatocytic and vascular markers. Thus, based on histology and immunohistochemistry, a diagnosis of CCMMT was made. This case presents the diagnostic challenges of CCMMT and discusses the differential diagnosis with a literature review.

Malignant retroperitoneal PEComa: A case report with emphasis on radiological findings.

A perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm with distinctive perivascular epithelioid cells that usually demonstrates myomelanocytic differentiation. PEComas can arise in various organs and generally are benign. Uncommonly PEComas have been documented to be malignant with metastasis most frequently to the lung, liver, lymph nodes, and bone. Here, we present the case of a 59-year-old male with a malignant retroperitoneal PEComa with confirmed metastasis to the femur and suspected metastasis to the liver and lung. The purpose of this case study is to present the progression and findings of a metastatic malignant PEComa.

Primary Perivascular Epithelioid Cell Tumor of the Lung: A Case Report.

Perivascular epithelioid cell tumors (PEComas) are very rare mesenchymal neoplasms, composed of histologically and immunohistochemically distinctive cells that form a sheet-like appearance around vessel lumens. Although most are benign, a malignant subset does exist, complicating clinical diagnostic efforts. Proper evaluation and management are thus essential for long-term patient survival. Herein, we present a rare case of a benign pulmonary PEComa that was diagnosed postoperatively in a 45-year-old woman.

Perivascular epithelioid cell tumors of the liver misdiagnosed as hepatocellular carcinoma: Three case reports.

BACKGROUND: Hepatic perivascular epithelioid cell neoplasms (PEComas) are rare. Diagnostic and treatment experience with hepatic PEComa remains insufficient. CASE SUMMARY: Three hepatic PEComa cases are reported in this paper: One case of primary malignant hepatic PEComa, one case of benign hepatic PEComa, and one case of hepatic PEComa with an ovarian mature cystic teratoma. During preoperative imaging and pathological assessment of intraoperative frozen samples, patients were diagnosed with hepatocellular carcinoma (HCC), while postoperative pathology and immunohistochemistry subsequently revealed hepatic PEComa. Patients with hepatic PEComa which is misdiagnosed as HCC often require a wider surgical resection. It is easy to mistake them for distant metastases of hepatic PEComa and misdiagnosed as HCC, especially when it's combined with tumors in other organs. Three patients eventually underwent partial hepatectomy. After 1-4 years of follow-up, none of the patients experienced recurrence or metastases. CONCLUSION: A clear preoperative diagnosis of hepatic PEComa can reduce the scope of resection and prevent unnecessary injuries during surgery.

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.

Single-center Experience in the Diagnosis and Treatment of Hepatic Perivascular Epithelioid Cell Neoplasm.

BACKGROUND AND AIMS: Perivascular epithelioid cell neoplasms (PEComas) are a rare type of mesenchymal neoplasm and their preoperative diagnosis is challenging. In this study, we summarized the experience from a single medical center to study the examinations, clinical presentations, and pathological and histological characteristics of PEComas in the liver in order to optimize overall understanding of the diagnosis and treatment of these neoplasms. METHODS: We conducted a retrospective analysis to investigate the clinical and pathological characteristics as well as imaging presentations of 75 patients diagnosed with hepatic PEComa in The First Affiliated Hospital of Zhejiang University between April 2010 and April 2020. RESULTS: Among the 75 patients, 52 were women, and the median age was 48 years. Most patients had no specific symptoms, and two were admitted to the hospital for a second time owing to relapse. All patients underwent surgical resection. Histologically, 38 patients had classical angiomyolipoma (AML) and 37 had epithelioid AML. The PEComas were accompanied by positive immunohistochemical expression of HMB45, Melan-A, and smooth muscle actin. Follow-up data were obtained from 47 of the total 75 patients, through October 2020. Two patients had metastasis after surgery. CONCLUSIONS: AML is the most common type of hepatic PEComa. There are no specific symptoms of hepatic PEComa, and serological examinations and imaging modalities for accurate preoperative diagnosis are lacking. Epithelioid AML should be considered a tumor of uncertain malignant potential; however, the prognosis of PEComa after resection is promising.

Advancements in the diagnosis and treatment of renal epithelioid angiomyolipoma: A narrative review.

Renal epithelioid angiomyolipoma (EAML) is a unique subtype of angiomyolipoma that contains a variety of cytoplasmic-rich, eosinophilic cytoplasm epithelioid cells in addition to mature adipocytes, hyaline thick-walled vessels, and smooth muscle-like spindle cells. In recent years, increasing evidence has shown that EAML is a potentially malignant tumor. Due to the lack of typical clinical manifestations and imaging features, it is difficult to diagnose before surgery, and the diagnosis mainly depends on postoperative histopathological examination. With the advancement of pathological diagnostic techniques, more EAML cases has been discovered, but clinicians still lack a comprehensive understanding of EAML. This review comprehensively describes some pathological and clinical features of EAML, with special attention to the pathogenesis and treatment of malignant EAML in order to assist with clinical diagnosis and treatment.

A Rare Case of Epithelioid Hemangioma Presenting as an Isolated Sacral Mass.

Epithelioid hemangioma (EH) is an uncommon benign vascular tumor of mesenchymal origin. It mainly presents as expanding nodules around the ear, the forehead, and long bones. Only a handful of cases have been found in cervical, thoracic, lumbar, and sacral vertebrae as lytic lesions with pain and neurological impairment. We present the case of a 36-year-old female with an incidental finding of a sacral mass along with inguinal lymphadenopathy on imaging. Initially, there were no symptoms. The mass gradually progressed and later showed an extraosseous extension with involvement of sacral neural foramina and nerve roots causing severe low back pain and weakness of the left lower extremity. Differential diagnoses initially included secondary metastases and chordoma. However, the biopsy of the mass revealed findings consistent with an EH. To our knowledge, this is the first case of EH presenting as an isolated mass in the sacrum and the third case of EH involving the sacrum in continuation with other vertebrae. EH should be in our differential diagnoses when there is a sacral mass.