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.

A retrospective clinical analysis of 11 cases of PEComa from different sites.

PURPOSE: The objective of this paper is to offer a thorough examination of the clinical presentations, etiology, and treatment strategies associated with perivascular epithelioid cell tumors (PEComas). METHODS: This retrospective study examined the comprehensive archival data of PEComa cases diagnosed at Beijing Hospital from 2015 to 2023. The pathology slides of all patients were thoroughly reassessed by two experienced pathologists. A thorough retrospective analysis was undertaken, incorporating clinicopathological data including gender, age at diagnosis, initial clinical manifestations, signs, disease onset site, tumor markers, imaging findings, therapeutic modalities, pathological features, immunohistochemical profiles, treatment responses, and prognostic indicators. Patients were evaluated for disease severity according to established pathological classification criteria and were followed up until the designated analysis cut-off date. In instances where patients were unable to be monitored on-site, they were contacted via telephone for postoperative follow-up inquiries. RESULTS: This study included 11 patients with ages ranging from 17 to 66 years old, presenting with the disease in multiple anatomical sites, including the retroperitoneum (2/11), liver (4/11), kidney (4/11), lung (1/11), and broad ligament of the uterus (1/11). Most patients presented with non-specific clinical symptoms and were subsequently diagnosed with space-occupying lesions upon physical examination. The tumor demonstrated progressive growth and enlargement, which could result in compression of neighboring organs. Preoperative imaging alone is insufficient for a definitive diagnosis of PEComa, but MRI can provide an initial evaluation of the tumor's potential malignancy. Molecular marker testing specific to PEComa, such as HMB-45 (90.0%), SMA (81.8%), Melan-A (90.9%), vimentin (90.9%), and Desmin (36.3%), was conducted on all patients. No adjuvant therapies were administered postoperatively. Upon analysis, no instances of relapse at the primary site or the development of new tumors at other sites were observed. Regular imaging reviews of three patients with malignant PEComa post-surgery showed no evidence of recurrence. CONCLUSIONS: The clinical presentation, tumor biomarkers, and imaging characteristics of PEComa lack specificity, necessitating dependence on pathology and immunohistochemistry for precise diagnosis. The mainstay of treatment consists of surgical resection, with patients typically experiencing a favorable prognosis.

Primary Liver Perivascular Epithelioid Cell Tumor (PEComa): Case Report and Literature Review.

A primary liver perivascular epithelioid cell tumor (PEComa) is an extremely rare entity. In this article, we present a case report with a review of the literature on the patients diagnosed with primary liver PEComa and an elaboration of diagnostic and treatment modalities. A systematic literature search was conducted using the terms "perivascular epithelioid cell tumor", "PEComa", "liver", and "hepatic". All articles describing patients diagnosed with primary liver PEComa were included. We identified a total of 224 patients of primary liver PEComa from 75 articles and a case from the present study with a significant preponderance of females (ratio 4:1) and with a mean age of 45.3 ± 12.1 years. Most of the patients (114 out of 224, 50.9%) were asymptomatic. A total of 183 (81.3%) patients underwent surgical hepatic resection at the time of diagnosis, while 19 (8.4%) underwent surveillance. Recurrence and metastases were detected in seven (3.1%) and six (2.7%) patients, respectively. In conclusion, surgical resection remains the cornerstone of therapy; however, the presence of nonspecific imaging features makes it difficult to reach a definite diagnosis preoperatively. Therefore, a multidisciplinary approach should be the gold standard in selecting the treatment modality.

A case of pancreatic PEComa with prominent inflammatory cell infiltration: the inflammatory subtype is a distinct histologic group of PEComa.

BACKGROUND: PEComa is a mesenchymal tumor that can occur in various organs including the uterus and soft tissues. PEComas are composed of perivascular epithelioid cells, and angiomyolipoma (AML), clear cell sugar tumor (CCST), and lymphangiomyomatosis (LAM) are considered lesions of the same lineage as tumors of the PEComa family. Histologically, a common PEComa shows solid or sheet-like proliferation of epithelioid cells. This is accompanied by an increase in the number of dilated blood vessels. Here, we report a case of pancreatic PEComa with marked inflammatory cell infiltration. CASE PRESENTATION: A 74-year-old male patient underwent an appendectomy for acute appendicitis. Postoperative computed tomography and magnetic resonance imaging revealed a 30 × 25 mm non-contrast-enhanced circular lesion in the tail of the pancreas. The imaging findings were consistent with a malignant tumor, and distal pancreatectomy was performed. Histologically, most area of the lesion was infiltrated with inflammatory cells. A few epithelioid cells with large, round nuclei, distinct nucleoli, and eosinophilic granular cytoplasm were observed. Spindle-shaped tumor cells were observed. Delicate and dilated blood vessels were observed around the tumor cells. Immunohistochemically, the atypical cells were positive for αSMA, Melan A, HMB-45, and TFE3. The cytological characteristics of the tumor cells and the results of immunohistochemical staining led to a diagnosis of pancreatic PEComa. CONCLUSIONS: A histological variant known as the inflammatory subtype has been defined for hepatic AML. A small number of tumor cells present with marked inflammatory cell infiltration, accounting for more than half of the lesions, and an inflammatory myofibroblastic tumor-like appearance. To our knowledge, this is the first report of pancreatic PEComa with severe inflammation. PEComa is also a generic term for tumors derived from perivascular epithelioid cells, such as AML, CCST, and LAM. Thus, this case is considered an inflammatory subtype of PEComa. It has a distinctive morphology that is not typical of PEComa. This histological phenotype should be widely recognized.

Clinicopathological features of two ultra-rare cases of malignant perivascular epithelioid cell tumors (PEComas) involving the uterus with recent updates.

Malignant perivascular epithelioid tumors (PEComas) involving the uterus are uncommon. Herein, we present the clinicopathological features of two such cases, including their diagnostic implications with recent updates. A 62-year-old lady presented with vaginal bleeding. Ultrasonogram revealed a heterogeneous uterine mass. She underwent an endometrial biopsy and total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH-BSO), which revealed a 3.2 cm-sized proliferative tumor in the fundus. A 45-year-old lady presented with recurrent abdominal pain. She underwent cytoreductive surgery twice with adjuvant chemotherapy for multiple tumors and TAH-BSO for a uterine tumor, 2 years before. Microscopic examination of both tumors revealed markedly atypical, polygonal-shaped/epithelioid tumor cells containing eosinophilic cytoplasm and arranged in a nesting pattern with intervening thin-walled blood vessels, mitotic figures (≥ 6/10 high power fields (hpfs)), and tumor necrosis. Tumor infiltration was more than half the myometrial thickness in the first tumor and pelvic nodal metastasis. The second tumor revealed rhabdoid-like and vacuolated cells along with "spider-like" giant cells. Immunohistochemically, both the tumors were positive for HMB45 and desmin, while negative for epithelial markers. Additionally, the second tumor was positive for smooth muscle actin (SMA) and TFE3. Both patients developed tumor recurrences. In view of multiple tumor deposits, the second patient was induced with a mammalian target of rapamycin (m-TOR) inhibitor (everolimus) but unfortunately died of the disease. Malignant PEComas involving the uterus are ultra-rare, aggressive tumors. An index of suspicion, based on certain histomorphological features, supported by immunohistochemical expression of myomelanocytic markers is necessary for a correct diagnosis. Certain PEComas display TFE3 positivity. A correct diagnosis has significant implications, including an aggressive clinical course and the possibility of targeted therapy, especially in recurrences or metastasis.

Hepatic perivascular epithelioid cell tumors: The importance of preoperative diagnosis.

Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors (PEComas) because PEComas are mainly benign tumors and may not require surgical intervention. By analyzing the causes, properties and clinical manifestations of PEComas, we summarize the challenges and solutions in the diagnosis of PEComas.

Hepatic perivascular epithelioid cell tumors: Benign, malignant, and uncertain malignant potential.

In 2013, the World Health Organization defined perivascular epithelioid cell tumor (PEComa) as "a mesenchymal tumor which shows a local association with vessel walls and usually expresses melanocyte and smooth muscle markers." This generic definition seems to better fit the PEComa family, which includes angiomyolipoma, clear cell sugar tumor of the lung, lymphangioleiomyomatosis, and a group of histologically and immunophenotypically similar tumors that include primary extrapulmonary sugar tumor and clear cell myomelanocytic tumor. Clear cell tumors with this immunophenotypic pattern have also had their malignant variants described. When localizing to the liver, preoperative radiological diagnosis has proven to be very difficult, and most patients have been diagnosed with hepatocellular carcinoma, focal nodular hyperplasia, hemangioma, or hepatic adenoma based on imaging findings. Examples of a malignant variant of the liver have been described. Finally, reports of malignant variants of these lesions have increased in recent years. Therefore, we support the use of the Folpe criteria, which in 2005 established the criteria for categorizing a PEComa as benign, malignant, or of uncertain malignant potential. Although they are not considered ideal, they currently seem to be the best approach and could be used for the categorization of liver tumors.

Nuestra experiencia en el tratamiento del PEComa hepático / Our experience in the surgical treatment of liver PEComa

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PEComa (neoplasia de células epiteliodes perivasculares) asociado con cáncer papilar de tiroides bilateral sincrónico / PEComa (Perivascular Epithelioid Cell Neoplasms) associated with synchronous bilateral papillary thyroid cancer

Resumen Introducción: Los tumores de células epitelioides perivasculares (PEComas) son neoplasias poco frecuentes de origen mesenquimal. Estos incluyen el angiomiolipoma epitelioide (EAML), una neoplasia con potencial maligno y cuya presentación simultánea con cáncer de tiroides es bastante rara. Presentación del caso: Hombre de 40 años con masa de crecimiento rápido en relación con polo inferior derecho de tiroides e infiltración de tráquea. La TAC abdominopélvica contrastada muestra múltiples masas renales con masa dominante en polo superior izquierdo. El estudio histopatológico de tiroides evidenció una lesión en lóbulo derecho correspondiente a cáncer papilar de tiroides (PTC) de variante de células altas y una segunda neoplasia en el lóbulo contralateral correspondiente a PTC moderadamente diferenciado de variante clásica. En riñón se encontró una lesión correspondiente a EAML, con células de aspecto epitelioide equivalentes al 40%. Discusión: El presente artículo corresponde al primero en la literatura en describir la presentación simultánea de EAML con PTC bilateral sincrónico (SBiPTC). Se describe una vía molecular común, que corresponde a la vía TSC/mTOR, la prevalencia de SBiPTC y los marcadores inmunohistoquímicos para diagnóstico de EAML.

Abstract Introduction: Perivascular Epithelioid Cell Neoplasms (PEComas) are uncommon tumors of mesenchymal origin. These ones include the epithelioid angiomyolipoma (EAML), a tumor with malignant potential and whose simultaneous presentation with thyroid cancer is quite rare. Presentation of case: Forty years old man with fast-growing mass in relation to lower right thyroid pole and tracheal infiltration. Abdominopelvic contrast-enhanced CT shows multiple renal masses with dominant mass in the left upper pole. Thyroid histopathology showed a lesion in right lobe corresponding to tall cell variant of papillary thyroid cancer (PTC) and a second neoplasm in the contralateral lobe corresponding to classical variant of moderately differentiated PTC. In the kidney was found a tumor corresponding to EAML with epithelioid aspect cells equivalent to 40%. Discussion: This article corresponds to the first in the literature to describe the simultaneous presentation of EAML with synchronous bilateral PTC (SBiPTC) and its possible association. A common molecular pathway corresponding to the TSC/mTOR pathway is described, as well as SBiPTC prevalence and immunohistochemical markers for EAML diagnosis.

Tumor de células epitelioides perivasculares de íleon. Descripción de un caso / Perivascular epithelioid cell tumor of the ileum. A case report

Los tumores de células epiteliodes perivasculares son tumores de células epiteliales vasculares con características inmunohistoquímicas de músculo liso y células melanocíticas. Los gastrointestinales son infrecuentes. El tratamiento es quirúrgico aunque existen datos que indican buena respuesta a la rapamicina (AU)

Perivascular epithelioid cell tumors (PEComa) are tumors of perivascular epithelioid cells with immunohistochemical features of smooth muscle and melanocytic tumors. The PEComa of the gastrointestinal tract is rare. The treatment is surgical, although there are data that suggest a good response to rapamycin (AU)

PEComa, un raro tumor de células epiteloides / PEComa, a rare epithelioid cell tumor

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Tumor de células epiteliales perivasculares (PECOma) de origen pancreático. Descripción de un caso y revisión de la literatura / Pancreatic perivascular epithelial cell tumour (PECOma). Case report and literature review

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Angiomiolipoma epitelioide/PEComa hepático e hiperplasia nodular focal en una paciente con antecedentes de melanoma cutáneo / Hepatic epithelioid angiomyolipoma/PEComa and focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma

Los tumores de células epitelioides perivasculares (PEComas) hepáticos son lesiones mesenquimales poco comunes. La ocurrencia simultánea de PEComas y otras lesiones hepáticas es inusual, con solo dos reportes de casos adicionales en la literatura inglesa. Reportamos un caso de PEComa primario hepático asociado con una hiperplasia nodular focal en una paciente con antecedentes de melanoma cutáneo. El diagnóstico radiológico fue sugestivo de adenoma hepático, por lo que se realizó una resección segmentaria hepática. El tumor estaba constituido por una proliferación de células epitelioides, tejido adiposo y fibras de músculo liso entremezcladas con vasos sanguíneos. Las células tumorales mostraron positividad difusa e intensa para HMB-45, Melan-A y actina de músculo liso, siendo negativas para Hepatocyte, S100, MITF y BRAF. No se detectó mutación BRAFV600 en el estudio por biología molecular. El diagnóstico patológico final fue de angiomiolipoma epitelioide hepático/PEComa. Se realiza una discusión del diagnóstico diferencial de los PEComas hepáticos

Hepatic perivascular epithelioid cell tumors (PEComas) are uncommon mesenchymal neoplasms. PEComas concurrent with other hepatic lesions is a very rare occurrence, with only two previously reported cases. We report a primary hepatic PEComa associated with focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma. Diagnostic imaging studies suggested a hepatic adenoma and the patient underwent a segmentectomy. The tumor was mainly composed of epithelioid cells, adipose tissue and smooth muscle fibers intermixed with blood vessels. The neoplastic cells were diffusely immunoreactive for HMB-45, Melan-A and smooth muscle actin, but not for Hepatocyte, S100, MITF or BRAF. Molecular studies were negative for BRAFV600 mutation. The final diagnosis was hepatic epithelioid angiomyolipoma/PEComa. The differential diagnosis of hepatic PEComa is discussed