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.

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.

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.

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.

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.

Pancreatic PEComa, a not so uncommon neoplasm? Systematic review and therapeutic update. / PEComa pancreático ¿una neoplasia no tan infrecuente? Revisión sistemática y actualización clínico-terapéutica.

Pancreatic PEComas are extremely rare neoplasms with malignant potential, which mostly affect middle-aged women and are characterized by presenting melanocytic and myogenic markers in immunohistochemical analysis. There are no symptoms or pathognomonic imaging tests, so the diagnosis is established with the analysis of the surgical specimen or the FNA obtained with preoperative endoscopic ultrasound. The mean treatment consists on radical excision, adapting the intervention to the location of the tumor. To date, 34 cases have been described; however, more than 80% of them have been reported in the last decade, which suggests that it is a more frequent pathology than expected. A new case of pancreatic PEComa is reported and a systematic review of the literature is carried out according to the PRISMA guidelines with the aim of divulge this pathology, deepening its knowledge and updating its management.

[Perivascular epithelioid cell tumor of the lung: a clinicopathological analysis of eight cases].

Objective: To investigate the clinicopathological features of perivascular epithelioid cell tumor (PEComa) of the lung. Methods: Eight PEComa cases of the lung diagnosed at the First Affiliated Hospital of Soochow University, Suzhou, China from July 2008 to December 2021 were collected and subject to immunohistochemical staining, fluorescence in situ hybridization and next generation sequencing. The relevant literature was reviewed and the clinicopathological features were analyzed. Results: There were 5 males and 3 females, aged from 18 to 70 years (mean 39 years). There were 3 cases of the right upper lung, 3 cases of the left lower lung, 1 case of the left upper lung and 1 case of the right middle lung. Seven cases were solitary and 1 case was multifocal (4 lesions). Seven cases were benign while one was malignant. The tumors were all located in the peripheral part of the lung, with a maximum diameter of 0.2-4.0 cm. Grossly, they were oval and well circumscribed. Microscopically, the tumor cells were oval, short spindle-shaped, arranged in solid nests, acinar or hemangiopericytoma-like patterns, with clear or eosinophilic cytoplasm. The stroma was rich in blood vessels with hyalinization. Coagulated necrosis and high-grade nuclei were seen in the malignant case, and calcification was seen in 2 cases. Immunohistochemically, the tumor cells were positive for Melan A (8/8), HMB45 (7/8), CD34 (6/8), TFE3 (4/7), and SMA (3/8). All cases were negative for CKpan and S-100. TFE3 (Xp11.2) gene fusion was examined using the TFE3 break-apart fluorescence in situ hybridization in 5 cases, in which only the malignant case was positive. The next generation sequencing revealed the SFPQ-TFE3 [t(X;1)(p11.2;p34)] fusion. Follow-up of the patients ranged from 12 to 173 months while one patient was lost to the follow-up. The malignant case had tumor metastasis to the brain 4 years after the operation and then received radiotherapy. Other 6 cases had no recurrence and metastasis, and all the 7 patients survived. Conclusions: Most of the PEComas of the lung are benign. When there are malignant morphological features such as necrosis, high-grade nuclei or SFPQ-TFE3 gene fusion, close follow-up seems necessary.

Clinicopathological features of primary malignant perivascular epithelioid cell tumors of ureter: Histologic-radiologic correlation.

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor that is mainly seen in middle-aged women. PEComa originating in the ureter is extremely rare it is unclear whether they display typical clinical and radiographic features seen elsewhere. Herein, we report findings from 2 cases of primary PEComa of the ureter that we classified as malignant. Case 1: A 45-year-old woman was admitted to the hospital with intermittent distension in her waist. After appropriate imaging, the right ureter and right kidney were excised under general anesthesia. The tumor measured 1.4 cm. Microscopically, the tumor displayed infiltrative growth, >2 mitoses per 10 high power fields (HPF), necrosis, and lympho-vascular invasion. Case 2: A 30-year-old woman was admitted to the hospital due to hematuria 20 days duration. The left ureter and left kidney were ultimately excised under general anesthesia. The tumor measured 2 cm. Microscopically, the tumor showed infiltrative growth and >2 mitoses/10 HPF. Our cases were diagnosed as malignant PEComa. No disease recurrence was observed in either of the two patients during the postoperative follow-up period. Malignant primary ureteral PEComa is very rare. The clinical manifestations are not specific, and it is usually misdiagnosed as a malignant neoplasm on imaging. Therefore, its diagnosis requires pathological examination and immunohistochemical analysis of the sampled or resected tumor. Treatment requires a complete surgical resection and regular clinical follow-up.

Treatment of malignant perivascular epithelioid cell tumor (PEComa) on the knee with an anterolateral thigh free flap: A case report.

RATIONALE: The World Health Organization defines a perivascular epithelioid cell tumor (PEComa) as a mesenchymal neoplasia composed of perivascular epithelioid cells with characteristic morphological and immunohistochemical features. Although PEComas have the potential to behave in a malignant fashion, malignant PEComas are extremely rare. PATIENT CONCERNS: An 83-year-old man visited our clinic presented with palpable, painless, and movable mass in the right knee area. DIAGNOSES: Malignant PEComa was diagnosed by incisional biopsy. No metastases was confirmed by radiologic imaging including PET/CT, magnetic resonance imaging, high resolution computed tomography. INTERVENTIONS: We performed wide excision of the mass and used an anterolateral thigh free flap to reconstruct the defect on the right knee. OUTCOMES: The permanent histopathology showed malignant PEComa was totally resected. The flap which was performed to cover the defect was survived and the patient discharge without any complications. LESSONS: PEComa can metastasize to various anatomical regions. Although there is no established standardized treatment, radical resection is still considered the cornerstone of treatment. Rapid and appropriate defect coverage is important to improve the patient's prognosis.

Rare perivascular epithelial cell tumor of the colon 18F-FDG PET/CT imaging: A case report.

RATIONALE: Neoplasms with perivascular epithelioid cell differentiation (PEComas) are mesenchymal tumors that rarely occur in the colon. Here, we report the occurrence of a malignant PEcoma in the colon using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). PATIENT CONCERNS: A 55-year-old woman was admitted to the hospital with abdominal pain for 10 days and a self-induced abdominal mass for 3 days. 18F-FDG PET/CT imaging showed a large hypermetabolic nodule and mass in the right mid-upper abdomen with heterogeneous density and a further increase in metabolism on the delayed scan. DIAGNOSES: PEComa of the colon. INTERVENTIONS: Tumor resection was performed. OUTCOMES: The patient is well after 2 months of treatment, pending further follow-up. LESSONS: Malignant perivascular epithelioid cell tumors originating in the colon are extremely rare, and our report suggests that PEComa should be considered as a differential diagnosis for 18F-FDG gastrointestinal malignancies. Additionally, 18F-FDG PET/CT may play a key role in the staging and extent of lesions in intestinal malignancies.

Perivascular epithelioid cell tumor (PEComa) of the liver. An extremely rare diagnosis.

Hepatic PEComa are tumors that show perivascular epithelioid cell differentiation. Scarcely published, its management is based on small case series and currently its treatment of choice is surgical resection. We present a clinical case of a 74-year-old woman who underwent surgery at our hospital for a benign hepatic PEComa.