Perivascular Epithelioid Cell Differentiation Research Articles

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

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). 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. PEComa of the colon. Tumor resection was performed. The patient is well after 2 months of treatment, pending further follow-up. 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.

Sporadic Renal Angiomyolipoma: Can We Adopt a Uniform Management Protocol?

AbstractRenal angiomyolipomas (AMLs), formerly known as PEComas (tumors showing perivascular epithelioid cell differentiation) are common benign renal masses composed of a varying ratio of fat, blood vessels, and smooth muscles. They are largely asymptomatic and diagnosed incidentally on imaging.The adipose tissue content is the factor that gives AMLs their characteristic appearance on imaging and makes them easily identifiable. However, the fat-poor or fat-invisible varieties, which are difficult to differentiate radiologically from renal cell carcinomas (RCCs), present a diagnostic challenge. It is thus essential to establish the diagnosis and identify the atypical and hereditary cases as they require more intense surveillance and management due to their potential for malignant transformation.Multiple management options are available, ranging from conservative approach to embolization and to the more radical option of nephrectomy. While the indications for intervention are relatively clear and aimed at a rather small cohort, the protocol for follow-up of the remainder of the cohort forming the majority of cases is not well established. The surveillance and discharge policies therefore vary between institutions and even between individual practitioners. We have reviewed the literature to establish an optimum management pathway focusing on the typical AMLs.

A case of caecal "PECOMA": An uncommon entity.

Introduction and importanceWorld Health Organization (WHO) defines PEComa as a mesenchymal tumor composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. The symptoms and clinical signs of PEComa patients are nonspecific. Hence, diagnosis is usually difficult. Since it's a rare diagnosis, further research might help in understanding the disease better.Case presentationThe patient in this study was an asymptomatic patient, who did colonoscopy as part of a regular check-up. A submucosal cecal tumor was detected in colonoscopy, and apart from that, all other investigative parameters were within normal limits.Clinical discussionLaparoscopic Ileocecectomy was performed, and the histopathology report was suggestive of Pecomatosis (PEComa – Perivascular epithelioid cell tumor). The PEComas, neoplasms with perivascular epithelioid cell differentiation, are mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells (PEC). The characteristic features of PEC are the positivity of melanocytic markers and smooth muscle markers.ConclusionPerivascular epithelioid tumors are mostly rare in the gastrointestinal tract, and even more unusual to be detected in Cecum. Surgery is the mainstay of the treatment, although, adjuvant therapy has been tried in recent times. The patients have to be kept in close follow-up, as there are reported cases of recurrences and distant metastasis.

MR findings of uterine PEComa in patients with tuberous sclerosis: report of two cases

Tuberous sclerosis complex (TSC), a rare autosomal dominant neurocutaneous disorder, is characterized by the presence of benign congenital tumors in multiple organs. Neoplasms with perivascular epithelioid cell differentiation (PEComas), including angiomyolipoma (AML) and lymphangioleiomyomatosis (LAM), can occur in association with TSC. This report describes two cases of uterine PEComas presenting characteristic MR imaging features reflecting pathological findings. From MR images, both cases showed single or multiple large, irregularly shaped or lobulated hemorrhagic lesions within the myometrium. They differed from typical adenomyotic cysts in their large size and irregular margins. Histopathologic analysis revealed that the hemorrhage was caused by adenomyosis and tumor cells that proliferated in surrounding stroma of the hemorrhagic lesions, compatible with PEComas. Microscopic observation revealed an infiltrative growth pattern of PEComas, with small nodules formed. The tumor lesions, however, were difficult to detect on MR images. The myometrium showed normal appearance on both T1-weighted and T2-weighted images in both cases. We speculate that PEComas may infiltrate extensively into the myometrium even when the myometrium shows almost normal radiologic appearance.

Angiomyolipome épithélioïde du rein : à propos d’une observation et discussion des critères de malignité

Renal epithelioid angiomyolipoma (E-AML) is a rare mesenchymal tumor of the kidney included in the family of tumor with perivascular epithelioid cell differentiation (PEComas) and is frequently associated with tuberous sclerosis complex. Since its clinical and radiological features are not specific, the diagnosis remained mostly pathological. Microscopically, E-AML demonstrate proliferation of more than 80% of epithelioid cells with atypia, often associated with necrosis, hemorrhage, mitotic activity and vascular invasion. Tumor's cells are immunohistochemically positive for melanocytic and smooth muscle markers. The pathologic prognostic predictors are not well known and the malignancy remained based on the identification of distant metastasis. We herein report a case of E-AML diagnosed in a 58-year-old woman and review analysis in the literature to discuss the prognostic indicators of malignancy useful for risk stratification of E-AML and to manage the patients.

PEComa of the terminal ileum mesentery as a secondary tumour in an adult survivor of embryonal rhabdomyosarcoma.

Perivascular epithelioid cell tumours (pecomas) are rare mesenchymal tumours that are characterized by perivascular epithelioid cell differentiation and immunoreactivity to myogenic and melanocytic markers. These tumours can be classified as benign, uncertain malignant potential, or malignant. Because of the rarity of pecomas, their cause and clinical prognosis remain unclear. To the best of our knowledge, no reports in the literature describe a pecoma of the terminal ileum mesentery as a secondary tumour in an adult survivor of childhood embryonal rhabdomyosarcoma, let alone any childhood cancer. Here, we present the case of a 27-year-old man with a pecoma involving the mesentery of the terminal ileum. At the age of 5, he had been treated with a combination of chemotherapy and high-dose pelvic radiation therapy for embryonal rhabdomyosarcoma, most likely arising from the posterior bladder wall. During routine follow-up 22 years after this patient's initial treatment, computed tomography imaging revealed a mass within the terminal ileum mesentery. The tumour was successfully treated with surgical resection, and pathology examination determined the mass to be a pecoma with uncertain malignant potential. This first case of a pecoma of the terminal ileum mesentery arising within a high-dose radiation therapy field as a secondary tumour in an adult survivor of childhood cancer highlights the importance of screening and surveillance in high-risk childhood cancer survivors treated with high-dose radiation therapy. Further research to build a better understanding of this remarkably rare tumour is warranted.

Laparoscopic Resection of Hepatic Angiomyolipoma - An Uncommon Primary Liver Tumor: A Case Report and Literature Review

PEComas are an uncommon group of mesenchymal neoplasms that exhibit perivascular epithelioid cell differentiation. The term PEComa includes a collection of different subcategories, such as lymphangioleimyomatosis, clear cell tumor of the lung, and angiomyolipoma (AML) which is the topic of discussion in this article. The main problem concerning the diagnosis of hepatic AML is the wide non-specific imaging findings, stressing the need for a tissue diagnosis. Histological examination of a hepatic AML shows different types of tissues such as smooth muscle cells, fat cells (adipocytes), and blood vessels. The ultimate method for diagnosing an AML case is through immunohistochemical examination. AML displays positive immunoreactivity to HMB-45 and Melan- A, and negative to CAM5.2 and AE1/AE3 as well as S100 of the melanoma. The management of hepatic AML has been a matter of debate between different groups, and in this article we discuss a hepatic AML case that presented to our group and was treated with a minimally invasive surgical procedure.

Retroperitoneal neoplasm with perivascular epithelioid cell differentiation: A case report and review of literature

The retroperitoneal neoplasm with perivascular epithelioid cell differentiation (PEComa) is an extremely rare pathological entity. In this article, we reported one case of a 45-year-old woman who was admitted to our hospital (The Second People’s Hospital of Hefei, China) for retroperitoneal neoplasm with perivascular epithelioid cell differentiation. The B ultrasonic examination showed echopoor in the region of cavitas pelvis. The histologic characteristics and immunohistochemical phenotype both revealed the neoplasm with perivascular epithelioid cell differentiation.

Multiple Perivascular Epithelioid Cell Tumors: Clear Cell Tumor of the Lung Accompanied by Angiomyolipoma of the Liver

Clear cell tumor (CCT) of the lung is very rare, and angiomyolipoma (AML) of the liver is also very rare. Both CCT and AML have been identified as a group of neoplasms with perivascular epithelioid cell differentiation (PEComa). We report a case with multiple PEComas of a combination of CCT of the lung and AML of the liver. The patient underwent surgical resection of an abnormal nodule of the lung 5 years after treatment of AML of the liver. The histological diagnosis of the pulmonary nodule was CCT. Neither lesion demonstrated malignant phenotypes, such as high mitotic activity, necrosis, or lymphovascular invasion. Each tumor of the lung and liver was solitary and differed from each other histologically. Therefore, these tumors were considered to be multifocal, not metastatic PEComas. This case is, to our knowledge, the first report of multiple PEComas of pulmonary CCT and hepatic AML. These findings suggest that patients with PEComas may require whole-body follow-up examinations because different subtypes of PEComas may occur multifocally.

Perivascular epithelioid cell tumor located retroperitoneally with pulmonary lymphangioleiomyomatosis: report of a case

Perivascular epithelioid cell neoplasms, also known as "PEComas", are unusual mesenchymal tumors, exhibiting perivascular epithelioid cell differentiation and characterized by a mixed myogenic and melanocytic phenotype. "PEComas not otherwise specified" (PEComas-NOS) are especially rare; consequently, there are no published large series, but only case reports. These tumors are rarely located retroperitoneally, with only about 15 such cases reported. We report a case of pulmonary diffuse lymphangioleiomyomatosis with large retroperitoneal PEComa-NOS in a 66-year-old woman. Treatment consisted only of tumor resection, without additional adjuvant therapy. We emphasize the importance of correct immunohistochemistry diagnosis, initiation of recommended treatment, and surveillance of this unique family of tumors.

Robotic Partial Adrenalectomy for 10-cm Angiomyolipoma

Abstract Introduction: Angiomyolipoma belongs to the family of PEComas. They are various mesenchymal tumors that all show perivascular epithelioid cell differentiation. Generally, the angiomyolipom...

Melanotic Xp11.2 Neoplasm of the Ovary

We describe a primary ovarian neoplasm, occurring in a 15-year-old female patient, with morphologic, immunohistochemical, and molecular genetic features identical to those of the very rare tumors of the kidney previously described as "melanotic Xp11 translocation renal cancer." This represents, to the best of our knowledge, the first report of a melanotic Xp11 translocation-associated neoplasm arising outside of the kidney. We discuss the relationship of these rare tumors to neoplasms showing perivascular epithelioid cell differentiation, in particular those showing TFE3 rearrangements.

Synchronous Transperitoneal Laparoscopic Resection of Right Retroperitoneal Schwannoma and Left Kidney Monotypic PEComa in the Presence of a Duplicated Inferior Vena Cava (IVC)

A 21-year-old female presented with a retroperitoneal mass in the right side and a centrally located renal mass in the left kidney with an aberrant vascular anatomy of a double inferior vena cava. The 2 tumors were radically excised by a transperitoneal laparoscopic approach in one session. Histopathologic examination revealed the right retroperitoneal lesion to be a schwannoma and the renal mass to be a cluster of monotypic neoplasms with perivascular epithelioid cell differentiation (PEComas). The latter is a rare tumor.

Sinonasal perivascular epithelioid cell tumor: Benign or malignant neoplasm?

Neoplasms showing perivascular epithelioid cell differentiation (PEComas) are uncommon tumors of the sinonasal tract. They are often misdiagnosed as angiomyolipoma or a simple benign tumor or polyp. We present a further case of a sinonasal PEComa and review the literature in an attempt to ascertain their malignant potential. Published evidence on invasiveness and characteristics were defined on systematic review. MEDLINE and EMBASE were searched from 1966 and 1980, respectively, to week 3 of December 2010. Publications reporting PEComa or angiomyolipoma were sought. Only those describing a sinonasal origin were included. Demographics, anatomic site, local invasion, recurrence rates, and mortality were recorded. A case report of a locally invasive intranasal PEComa is described. In addition to the case we present, 12 case reports were located (n = 13). The mean age of patients was 59.6 (SD, 14.98 years) years. The location was within the right sinonasal tract in 54% of cases, the left sinonasal tract in 38% of cases, and not reported in 8% of cases. Treatment focused on local surgical excision and this was achieved endoscopically in 100% of cases. Recurrence rate was 8%. Mean follow-up was 17.4 (SD, 20.68 months) months. Invasion was noted in 23% of cases. There was a single death recorded. PEComas of the paranasal sinuses and skull base appear to have a biological behavior different from simple benign angiomyolipomas reported elsewhere in the body. PEComa may be more intermediate or malignant in clinical behavior.

A proposal for creating a guideline for cancer registration of the fibromatosis, PEComa group, malignant lymphoma In Situ and dendritic cell tumors (III).

BackgroundUnderstanding the biologic behavior of a tumor is a prerequisite for tumor registration code assignment. The aim of this report was to propose appropriate behavior codes of the International Classification of Disease Oncology 3 (ICD-O3) to rare, yet pathologically interesting hematopoietic and soft tissue tumors.MethodsThe Study Group for Hematopathology, the Bone and Soft Tissue Pathology Study Group, and the Cancer Registration Committee prepared the questionnaire containing provisional behavior codes of selected diseases.ResultsIn situ lesions of mantle cell and follicular lymphomas, dendritic cell tumors, and neoplasms with perivascular epithelioid cell differentiation (PEComa), not otherwise specified were classified as malignant (-/3). The fibromatosis group, with the exception of lipofibromatosis, was proposed as benign (-/0). Lipofibromatosis and several diseases that belong to the PEComa group were proposed as uncertain malignant potential (-/1). For the hematologic and soft tissue tumors, 274 and 288 members of the Korean Society of Pathologists, respectively, provided opinions through questionnaire, and most responders showed agreement with the provisional behavior code proposed.ConclusionsThe determination of behavior codes for the rare diseases described in this study, especially those of the PEComa group or malignant lymphoma, could be viewed as impractical and premature, but this study provides the basis for future research on this topic.

Malignant PEComa of the adrenal gland

Perivascular epithelioid cell neoplasms, also known as PEComas, are unique mesenchymal tumors exhibiting perivascular epithelioid cell differentiation, characterized by a mixed myogenic and melanocytic phenotype. PEComas arising in visceral organs outside of the kidney, liver, and lung are rare, and often pose problems in diagnosis. Examples of this neoplasm originating in the adrenal gland are limited. The present report details the clinical and pathologic features of an unusual case of a pure epithelioid PEComa (epithelioid angiomyolipoma) of the adrenal gland exhibiting clinically malignant behavior in the form of pulmonary metastases, a feature not previously described in tumors of this site. The diagnosis was supported by immunohistochemical studies demonstrating expression of myoid and melanocytic antigens. The present case serves to emphasize the potential of PEComa for clinically aggressive behavior and the importance of distinguishing this tumor from other epithelioid neoplasms that are more commonly encountered in the adrenal gland.

Primary malignant gastric PEComa – Diagnostic and technical dilemmas

IntroductionThe World Health Organisation defines PEComa's as “a mesenchymal tumour composed of histologically and immunohistochemically distinctive perivascular cells”.1 These ubiquitous tumours show distinctive perivascular epithelioid cell differentiation and arise most commonly at visceral and abdominopelvic sites. Presentation of caseWe present a case of a forty-two year old man presenting to accident and emergency department with upper gastro-intestinal bleeding. He had a palpable epigatric mass on examination. He underwent a CT Scan Abdomen which displayed a tumour arising from the gastric wall. Upper GI endoscopy and biopsy was carried out and biopsied were taken for histological analysis. A primary gastric PEComa was diagnosed and the patient underwent distal polya gastrectomy and gastrojejunostomy. This is believed to be the first reported case of a Primary malignant gastric PEComa. DiscussionPerivascular epithelioid carcinomas were first described in 1943 as an abnormal myoblast in a case of renal angiomyolipoma. PEComas display a strong female predominance with a typical benign course. There are approximately 100 reported cases of PEComa to date, with 55 of which were malignant. PEComa's may be subdivided into benign, uncertain malignant potential and malignant. Their natural history can be very aggressive leading to multiple metastases and death as expected with a high-grade sarcoma. ConclusionThis case depicts the aggressive nature of malignant gastric PEComa's. The majority of PEComa's are benign in nature and have a better prognosis. We display here the challenges in ascertaining a definitive diagnosis and management of such patients due to limited clinical studies.

Concept of perivascular epithelioid cells and neoplasms with perivascular epithelioid cell differentiation

一、血管周上皮样细胞的由来 1991年意大利病理学者Pea等[1]在肺透明细胞糖瘤(CCST)和肾血管平滑肌脂肪瘤(AML)中同时观察到一种胞质透亮至淡嗜伊红色的上皮样细胞.随后的一些研究显示,CCST和AML均表达HMB45,电镜检测也观察到胞质内含前黑色素颗粒.鉴于此,Bonetti等[2]于1992年首次提出血管周上皮样细胞(PEC)这一概念,并在随后的文章中指出CCST和AML关系密切,同属一个家族,这个家族以含有表达HMB45的PEC为特征[3]。

Clinicopathological features of uterine neoplasms with perivascular epithelioid cell differentiation

To study the neoplasm with perivascular epithelioid cell differentiation (PEComa) with respect to their morphologic, immunohistochemical and clinical phenotypes. Three PEComas were included in this study, one located at the left uterine horn, and two presented as a mass in the uterine corpus. The tumors were examined by histopathology and immunohistochemistry. The lesions were composed of spindle, blunt epithelioid cells, with foci of, or scattered, cells showing adipose differentiation in two cases. The myomelanocytic differentiation was demonstrated, proving the diagnosis as PEComa. Mild nuclear atypia and focal necrosis was observed in one lesion, and the rest two showed malignant morphologic phenotypes including moderate nuclear atypia and coagulative necrosis. The mitotic and Ki67-labelling indices ranged from 0.5/10 HPF to 14/10 HPF and 0.6% to 7.0%, respectively. All of the three patients remain alive. Malignant nature of the two lesions with worrisome morphology was confirmed by occurrence of metastases after hysterectomy. PEComa is a rare tumor, occurring preferentially in the uterus. It is regarded as a tumor with uncertain malignant potential, but a minority of them shows malignant clinical behaviors. Some pathologic parameters including large tumor size, sheet-like necrosis, marked nuclear atypia, elevated mitotic index (> or = 10/10 HPF), aberrant mitotic figure and vascular invasion may help to establish a diagnosis of malignant PEComa.