Perivascular Epithelial Cell Research Articles

Retroperitoneal hamartoma mimicking angiomyolipoma: a case report and review of literature

BackgroundHamartoma refers to the excessive focal growth of cells and tissues in organs, which is between malformation and benign tumor. Hamartomas are commonly seen in the lung, but rare in the retroperitoneum.Main textAngiomyolipoma was also called hamartoma in the early years. Hamartoma was not separated from the concept of angiomyolipoma until perivascular epithelioid cells were found in angiomyolipoma. We reported a case of retroperitoneal hamartoma, which was suspected to be angiomyolipoma in the initial imaging findings and pathological frozen section, but the paraffin section was finally diagnosed as hamartoma. Due to the fusion of the tumor with the right psoas major muscle, it may need to be cut off for complete resection of tumor, which may damage the sacrococcygeal nerve and affect the postoperative activity function, so the tumor was just partially removed. After 6 and 22 months of follow-up, the patient was in good condition. CT re-examinations showed that the epibiotic right retroperitoneal mass size was 40 × 42 × 72 mm3 (6 months, length × width × height) and 40 × 45 × 81 mm3 (22 months, length × width × height). We describe this case and review the literature.ConclusionsIn conclusion, retroperitoneal hamartoma is rare and difficult to differentiate from angiomyolipoma, in which perivascular epithelial cells could be found on pathological paraffin sections.

Tuberous sclerosis complex: a complex case.

Tuberous sclerosis complex (TSC) is an inheritable disorder characterized by the formation of benign yet disorganized tumors in multiple organ systems. Germline mutations in the TSC1 (hamartin) or more frequently TSC2 (tuberin) genes are causative for TSC. The malignant manifestations of TSC, pulmonary lymphangioleiomyomatosis (LAM) and renal angiomyolipoma (AML), may also occur as independent sporadic perivascular epithelial cell tumor (PEComa) characterized by somatic TSC2 mutations. Thus, discerning TSC from the copresentation of sporadic LAM and sporadic AML may be obscured in TSC patients lacking additional features. In this report, we present a case study on a single patient initially reported to have sporadic LAM and a mucinous duodenal adenocarcinoma deficient in DNA mismatch repair proteins. Moreover, the patient had a history of Wilms’ tumor, which was reclassified as AML following the LAM diagnosis. Therefore, we investigated the origins and relatedness of these tumors. Using germline whole-genome sequencing, we identified a premature truncation in one of the patient's TSC2 alleles. Using immunohistochemistry, loss of tuberin expression was observed in AML and LAM tissue. However, no evidence of a somatic loss of heterozygosity or DNA methylation epimutations was observed at the TSC2 locus, suggesting alternate mechanisms may contribute to loss of the tumor suppressor protein. In the mucinous duodenal adenocarcinoma, no causative mutations were found in the DNA mismatch repair genes MLH1, MSH2, MSH6, or PMS2. Rather, clonal deconvolution analyses were used to identify mutations contributing to pathogenesis. This report highlights both the utility of using multiple sequencing techniques and the complexity of interpreting the data in a clinical context.

Pancreatic perivascular epithelial cell tumour (PECOma). Case report and literature review

Pancreatic perivascular epithelial cell tumour (PECOma). Case report and literature review

Remote Radiotherapy in the Treatment of Patients with Perivascular Epithelial Cell Tumors

The main method of treating rare mesenchymal tumors PEComas is surgical removal of the tumor and external-beam radiation therapy has historically been considered ineffective. However, the individual cases in the foreign literature as well as this article authors’ experience in the form of the clinical case provided in it shows the possibility of achieving some anti-tumor effect due to the use of aggressive variants of radiation therapy. The use of variations of stereotactic radiotherapy with high dose per fraction and sum dose as an neoadjuvant and definitive treatment looks promising.

Primary hepatic perivascular epithelioid cell neoplasm (PEComa) with fever in a 53-year-old man

A 53-year-old male patient, presenting merely with fever for a week, was admitted to the hospital. Contrast-enhanced CT showed a round inhomogeneous enhancement lesion on the early arterial phase and...

A Case of Perivascular Epithelioid Cell Tumor (PEComa) of the Uterus Associated with Tuberous Sclerosis Complex Diagnosed by Intra-Abdominal Bleeding from the Uterus

We report a case of perivascular epithelioid cell tumor (PEComa) of the uterus associated with tuberous sclerosis complex discovered as a result of intraabdominal bleeding. A 54-year-old woman visited the department of obstetrics and gynecology with chief complaints of genital bleeding and abdominal pain lasting three weeks. Abdominal computed tomography (CT) revealed intraabdominal bleeding from the uterine corpus. She had a history of bilateral renal angiomyolipoma, which was treated with partial bilateral nephrectomy at age 25. Moreover, pulmonary lymphangioleiomyomatosis was diagnosed at age 43. Both conditions were detected by the CT scan during this hospitalization. Immediately after the CT scans, the patient entered a state of hemorrhagic shock, and we performed an emergency simple total hysterectomy. Histopathological examination on the resected specimen yielded a diagnosis of uterine perivascular epithelial cell tumor (PEComa). After making a definitive diagnosis of tuberous sclerosis complex (TSC), systemic evaluation was performed. As a result, multiple skin and intracranial lesions characteristic of TSC were identified and we stated administration of everolimus.

Risk factors in pregnant women with an oncological diagnosis and their impact in the post-partum period.

e23166 Background: An oncological diagnosis during pregnancy, or the choice of motherhood following cancer may be accompanied by anxiety, distress and depression. The aim of the study is to explore the possible risk factors in the perinatal period in women who experienced an oncological diagnosis before or during pregnancy. Methods: 32 pregnant women (25 breast, 3 cervix, 1 lung, 1 Hodgkin's lymphoma, 1 perivascular epithelial cell neoplasia, 1 epatic PEComa) were assessed during their 3rd trimester (T1) and three months’ post-partum (T2). At T1 mood states and post-traumatic symptoms were evaluated, at T2 parenting stress and perceived quality of life (QoL). Results: Depression, anger and anxiety correlated with lower physical and psychological QoL in the post-partum. Moreover, mothers who expressed higher levels of fatigue and confusion during pregnancy are associated to lower levels of perceived psychological QoL. Women who manifested hypervigilance and hyperarousal during pregnancy were more likely to perceive lower psychological QoL three months after birth. Finally, post-traumatic symptoms of intrusiveness during pregnancy correlated with higher levels of parenting stress and higher risk of dysfunctional parenting, together with a stronger perception of having a child with a difficult temperament in the post-partum period. Conclusions: Mood states and post-traumatic symptoms can decrease the mother’s quality of life and heighten parental distress. These preliminary results suggest implementing psychological support for women with current or previous oncological diagnosis during pregnancy in order to prevent the onset of dysfunctional parenting and/or problem behaviours in their children. [Table: see text]

Perivascular epithelial cell tumor (PEComa) of the pancreas: a case report and review of previous literatures.

Perivascular epithelial cell tumors (PEComas), firstly described by Bonetti in 1992, are a family of mesenchymal tumor composed of perivascular epithelioid cells having epithelioid or spindle morphology and exhibiting melanocytic and myogenic immunoreactivities. We herein described a 61-year-old woman who presented with epigastric pain. Preoperative imaging studies showed that 7-cm-sized mass was located in pancreatic head and body, and pancreaticoduodenectomy was performed. Histological findings showed that the tumor was composed of clear epithelioid cells with abundant glycogen granules, which grew in a nested and alveolar pattern around blood vessels. The tumor cells showed immunoreactivities for HMB-45 but did not express epithelial or endocrine markers. These histological features indicated those of PEComa. This report underlines that we should recognize PEComa as a preoperative differential diagnosis of pancreatic tumors.

Angiomyolipoma and Malignant PEComa: Discussion of Two Rare Adrenal Tumors.

Angiomyolipoma and PEComa are rare tumors descending from perivascular epithelial cells (PECs), with distinctive IHC, morphological, and ultrastructural features. The kidney is the most frequent site of origin, but not the only one; however, adrenal gland angiomyolipomas are extremely rare. We describe two cases being found in the adrenal glands. Given the paucity of literature on the subject, more information on this disease is necessary for diagnosis and treatment. Here, we describe two complete case reports, from presentation to treatment and follow-up, along with imaging and microscopic pathology samples, and provide a comprehensive review as to the history and current literature available regarding these extremely rare tumors.

Giant renal angiomyolipoma – case report

renal angiomyolipoma is rare benign renal neoplasm composed of variable amounts of adipose tissue, smooth muscle tissue originating from perivascular epithelial cells and blood vessels. the incidence of renal angiomyolipoma is from 0,3% to 3,0%. tumors over 10 cm are diagnosed rare. clinically renal angiomyolipoma is usually associated with tuberous sclerosis complex and is more frequent in women. about 20% of these tumor are seen in patients with the tuberous sclerosis complex and 80% patients with tuberous sclerosis complex develop renal angiomyolipomas. the tumor is diagnosed by ultrasound, computer tomography scan (ct), magnetic resonance imaging (mri), histology and immunohistochemistry. the authors of this article presented a case of a 47-year-old caucasian woman who was admitted to the hospital because of giant renal angiomyolipoma. the patient underwent radical left nephrectomy without complications. the authors performed a literature review on giant renal angiomyolipoma treatment.

Update on Vascular Neoplasms

This article provides an update on vascular neoplasms. New immunohistochemical markers for the diagnosis of vascular neoplasms tumor 1, infantile hemangiomas, myopericytomas, perivascular epithelial cell tumors, acquired elastotic hemangiomas, vascular proliferations in radiated skin, and new histopathologic variants of AIDS-related Kaposi sarcoma are explored.

Fertility-sparing operation for recurrence of uterine cervical perivascular epithelioid cell tumor

Perivascular epithelioid cell tumors (PEComa) are mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelial cells. Although the uterine corpus seems to be one of the most prevalent sites of involvement, PEComa of the uterine cervix are very rare. Only four cervical PEComa cases have been described, and were treated with hysterectomy and radiotherapy.We report a case of a 24-year-old nulligravida woman who presented with acute abdominal pain and was diagnosed with a rupture of an ovarian chocolate cyst. Subsequent surgery revealed that the tumor arose in the uterus, and the histological diagnosis was uterine PEComa with low potential malignancy. Recurrent PEComa in the uterine cervix were excised twice, and she remains disease free 12 months after the last operation. To the best of our knowledge, this is the first report of recurrent cervical PEComa with fertility-preserving surgery. Estimating the malignant potential and appropriate surgery are essential for young patients with uterine PEComa.

Renal epithelioid angiomyolipoma: a malignant disease

Renal angiomyolipomas are recognized as clonal neoplasms with clonal chromosomal aberrations and a common progenitor cell, the perivascular epithelial cell (PEC). The epithelioid variant is a recently identified entity, characterized by predominance of PEC and a unique morphologic and immunohistochemical profile. There is accumulating evidence suggesting that renal epithelioid angiomyolipoma (REA) is a malignant disease. We searched the literature for descriptions of clinical behavior of REA. A Pubmed search was performed using the following key words: angiomyolipoma, epithelioid, perivascular epithelial cell or/and renal tumors. We reviewed a case of fatal REA at our institution. A pathologist reviewed slides to confirm the diagnosis. Upon review of 140 articles, 37 eligible articles were found including 10 articles describing the clinical course of REA. Almost all of the patients described, for whom there was a follow-up available, died of neoplastic progression of the disease, with liver, lung and bone metastases. Four cases were reclassified after retrospective pathology review, and they were fatal. Three of these had been misdiagnosed as renal cell carcinoma (RCC), while 1 was diagnosed as classic angiomyolipoma. Unlike commonly benign classic angiomyolipoma, REA behaves aggressively. It is crucial for the clinician to be aware of and identify this epithelioid variant as a malignant disease. It should be carefully differentiated from RCC. Resection alone may not be curative, and adjuvant therapy should be considered. A multimodality treatment approach needs to be explored for this newly recognized malignant variant renal angiomyolipoma.

Expression of nerve growth factor is upregulated in the rat thymic epithelial cells during thymus regeneration following acute thymic involution

Neuroimmune networks in the thymic microenvironment are thought to be involved in the regulation of T cell development. Nerve growth factor (NGF) is increasingly recognized as a potent immunomodulator, promoting “cross-talk” between various types of immune system cells. The present study describes the expression of NGF during thymus regeneration following acute involution induced by cyclophosphamide in the rat. Immunohistochemical stain demonstrated not only the presence of NGF but also its upregulated expression mainly in the subcapsular, paraseptal, and perivascular epithelial cells, and medullary epithelial cells including Hassall's corpuscles in both the normal and regenerating thymus. Biochemical data obtained using Western blot and RT-PCR supported these results and showed that thymic extracts contain NGF protein and mRNA, at higher levels during thymus regeneration. Thus, our results suggest that NGF expressed in these thymic epithelial cells plays a role in the T lymphopoiesis associated with thymus regeneration during recovery from acute thymic involution.

PEComa of the Upper Extremity: A Unique Case and Description of an Initial Response to Neoadjuvant Chemotherapy

Purpose. Tumors of the perivascular epithelial cell tumor (PEComa), first described in 1992, represent a rare soft tissue neoplasm of varying malignant potential. Cases of PEComa have been previously described in a few somatic and visceral sites, most notably in the gastrointestinal tract, genitourinary tract, and one extremity case in the thigh. To date, most malignant cases of PEComa have been resistant to chemotherapy, and as such, an appropriate therapy is not known. Case report. Here we describe the first case of PEComa of the upper extremity. Open biopsy revealed a high-grade malignant lesion, and the patient subsequently underwent both neoadjuvant therapy with doxorubicin, ifosfamide and mensa, and radiation therapy prior to wide surgical resection. After six cycles of chemotherapy, the tumor underwent an 80 reduction in size. Subsequent neoadjuvant radiation therapy of 5000 cGy did not further reduce the size of the tumor. Following limb sparing radical resection, pathology showed 20 necrosis within a high-grade malignant lesion. Twenty one months after beginning treatment, the patient shows no sign of local recurrence, but metastatic disease was confirmed after resection of a lung nodule. Conclusion. Given the favorable albeit partial response seen in this patient, the course of therapy outlined here may represent a good starting point for neoadjuvant treatment in a tumor with a historically bleak prognosis. In addition, the diagnosis of PEComa must now be entertained in the differential diagnosis of upper extremity soft tissue sarcoma.

Lack of response of a metastatic renal perivascular epithelial cell tumor (PEComa) to successive courses of DTIC based-therapy and imatinib mesylate

An 11 year-old girl presented with two large abdominal masses in the left flank and epigastrium and left supraclavicular lymphadenopathy. Subsequent investigations led to the diagnosis of metastatic perivascular epithelioid cell tumor (PEComa) arising from the left kidney. Effective treatment for this rare tumor is not yet known. The tumor did not respond to an initial treatment of two cycles of a dacarbazine (DTIC) based regimen. She was placed on a trial of imatinib mesylate based on tumor expression of c-KIT, a tyrosine kinase targeted by this drug. This report highlights the first documented case of the use of imatinib for PEComa. Lack of response and adverse effects of the drug required discontinuation of therapy.

Upregulation of TrkA neurotrophin receptor expression in the thymic subcapsular, paraseptal, perivascular, and cortical epithelial cells during thymus regeneration.

Neuroimmune networks in the thymic microenvironment are thought to be involved in the regulation of T cell development. Here, we report upon an examination of the expression of the TrkA neurotrophin receptor, the high affinity receptor for nerve growth factor, during regeneration following acute involution induced by cyclophosphamide in the rat thymus. Light and electron microscopic immunocytochemistry demonstrated enhanced expression of the TrkA receptor in the subcapsular, paraseptal, perivascular, and cortical epithelial cells during thymus regeneration. In addition, various morphological alterations, suggestive of a hyperfunctional and dynamic state, of the subcapsular, paraseptal, and perivascular epithelial cells were also observed. The presence of TrkA protein in extracts from the control and regenerating rat thymus was confirmed by western blot. Furthermore, RT-PCR analysis supported these results by demonstrating that thymic extracts contain TrkA mRNA at higher levels during thymus regeneration. Thus, our results suggest that the TrkA receptor located on the thymic subcapsular, paraseptal, perivascular, and cortical epithelial cells could play a role in the development of new T cells to replace T cells damaged during thymus regeneration.

Hepatic angiomyolipoma-misdiagnosis as hepatocellular carcinoma: A report of 14 cases.

Angiomyolipoma (AML) is a rare benign mesenchymal tumor of the liver, composed o f a varying heterogeneous mixture of three tissue components: blood vessels, smooth muscle, and adipose cells. It has recently been proposed that the perivascula r epithelial cell (PEC) is the common progenitor[1,2]. Since its first d escription by Ishak in 1976 [3], there have been more than 100 cases repo rted in the English literature[4-6]. With the advance of radiological techniques, many more tumors are being diagnosed by the means. But radiological findings of AML may only be suggestive of the lesion; its definitive diagnosis r equires histological confirmation[9-19]. Some authors regard renal and hepatic AMLs, pulmonary and soft tissue lymphangiomyomatosis[2], pulmon ary and pancreatic clear cell “sugar” tumor, and cardiac rhabdomyoma as closely related groups of tumors, based on their morphologic overlap and common immuno reactivity for HMB-45[1]. They show different microscopic appearances, however, according to their organ of origin. The goals of this study were to hig hlight more subtle morphology and to gain possible insights into the differential diagnosis that could provide important information about this disease.

P2 receptors in the thymus: expression of P2X and P2Y receptors in adult rats, an immunohistochemical and in situ hybridisation study.

The expression of the seven P2X receptor subtypes and of two P2Y receptors was examined immunohistochemically and by in situ hybridisation in thymi of adult male rats. P2X4, P2Y2 and 4 receptor mRNA colocalisation studies combining in situ hybridisation and immunohistochemistry were also carried out. P2X and P2Y receptors were found on thymocytes. P2X receptors were also abundant in cells of the thymic microenvironment, involved in control of T-cell maturation in vivo. We are the first to describe the expression of P2X4 receptors on thymocytes and confirm the finding of P2X1 and P2Y2 receptors on subpopulations of lymphocytes. P2X1,2,3,4 and 5 receptors were present in blood vessels of the thymus. P2X1,2 and 4 receptors were detected in vascular smooth muscle, while P2X3 receptors appeared to be associated with endothelial cells; some small arteries were positive for P2X5, possibly labelling vascular smooth muscle or fibroblasts in the adventitia. P2X2,3,6 and 7 receptors were found on thymic epithelial cells. P2X2 and 3 receptors were abundant on medullary epithelial cells, whilst P2X6 receptors were prominent in Hassall's corpuscles. P2X2 receptors were found on subcapsular and perivascular epithelial cells. P2X2,6 and 7 receptors were detected in epithelial cells along the thymic septa. Expression of P2X receptors was also investigated by Western blotting of crude thymic tissue extracts under reducing conditions. All seven P2X receptor subtypes were found to be dimers of approximately 70 kDa and 140 kDa molecular weight. ATP-mediated apoptosis and cell proliferation of thymocytes are discussed.

Role of the Perivascular Epithelium in the Histogenesis of Hassall's Corpuscles

Thirteen human thymuses and one thymoma were morphologically and immunohistologically investigated to define the histogenesis of Hassall's corpuscles (HCs). The following monoclonal antibodies: antisquamous cytokeratin on paraffin sections and TE-4 and TE-8 on frozen sections, were used to show the distribution of the epithelial components; PAL-E on frozen and anti-CD31 and anti-CD34 on paraffin sections detected the endothelial cell distribution. In the thymoma, epithelial onion-like structures, looking like true HCs, were found to originate from the perivascular epithelium lining dilatated spaces and some of them partially obliterated the space where the blood capillary showed thickened wall and endothelial regressive changes. Antisquamous cytokeratin stained: (1) in the thymus: subcapsular, medullary, and HC epithelial cells; (2) in the thymoma: epithelial cells lining the perivascular spaces and forming HCs. TE-4 stained: (1) in the thymus: the subcapsular and medullary epithelium; (2) in the thymoma: the epithelium lining the perivascular spaces and epithelial cells forming HCs. TE-8 stained: (1) in the thymus: HCs only; (2) in the thymoma: HCs and perivascular epithelial cells. PAL-E, CD31, and CD34, which specifically react with endothelial cells, stained remnants of capillary structures in the core of some HCs. The results indicate that: (1) corpuscular structures in thymoma originate from perivascular epithelium; (2) thymus medullary epithelial cells stained by cytokeratin and TE-4 correspond to perivascular epithelial cells whose staining is well documented in thymoma; (3) the subcapsular-perivascular epithelium and HCs represent different steps of differentiation of a single ectodermal cell lineage; (4) the PAL-E-, CD31-, and CD34-positive reaction in the core of some HCs suggests that the perivascular epithelium would be stimulated to transform into HCs as a consequence of endothelial changes with fragmentation of the capillary included in the perivascular space.