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.

Massive simultaneous hepatic and renal perivascular epithelioid cell tumor benefitted from surgery and everolimus treatment:A case report

BACKGROUND Perivascular epithelioid cell tumor(PEComa)is a rare mesenchymal neoplasm that predominantly affects the kidney and uterus.The occurrence of this tumor in the liver,particularly with simultaneous involvement of the liver and kidney,is exceedingly uncommon.Pathological diagnosis is the gold standard.PEComas usually show positive immunohistochemical staining for melanocytic(HMB-45,Melan-A)and myoid(SMA,muscle-specific actin)markers.CASE SUMMARY We presented a noteworthy case of malignant PEComa affecting both the liver and kidney in a 53-year-old man with tuberous sclerosis complex(TSC).FAT2 and TP73 mutations in the kidney were identified and positive expression of diagnostic markers including HMB-45,Melan A,and TFE3 were detected.In addition,we demonstrated that hepatic artery perfusion chemotherapy was ineffective for hepatic PEComa,while surgery remained the most effective approach.Everolimus showed an excellent efficacy in the postoperative treatment of the tumor.CONCLUSION Surgical treatment is preferred for malignant PEComa affecting liver and kidney,especially with TSC;everolimus is effective postoperatively.

Hepatic perivascular epithelioid cell tumor in three patients

Perivascular epithelioid cell tumor （PEComa） is a rare, soft tissue tumor that can occur in various locations. The present report included three patients （one male and two females; age range, 25-51 years） with hepatic PEComas. The collected data included the clinical manifestations, diagnosis, management, treatment, and prognosis. Since it is difficult to diagnose hepatic PEComas by imaging, the patients were diagnosed by tumor tissue examination such as immunohistochemistry, which was positive for HMB-45, Melan-A, and SMA on all slides. The tumor was composed of diverse tissues including smooth muscle, adipose tissue, and thick-walled blood vessels. During the follow-up period, one of the tumors was malignant （double-positive for CD34 and Ki-67） and recurred 3 months after surgery. In addition, malignant hepatic PECo- mas were reviewed in the literature, indicating that the majority of hepatic PEComas are benign, but few hepatic PEComas exhibit malignant behaviors in older female patients （〉50 years of age） with abdominal discomfort and pain, larger tumor size （〉10 cm）, or positive staining for CD34 and Ki-67. In conclusion, there is no effective method to diagnose PEComas. Currently, the diagnosis of PEComas depends on immunohistochemical staining. Tumor resection and close follow-up are the principal methods for the management of PEComas.

A perivascular epithelioid cell tumor of the stomach:An unsuspected diagnosis

Perivascular epithelioid cell tumor(PEComa) is a rare mesenchymal neoplasia and currently well recognized as a distinct entity with characteristic morphological,immunohistochemical and molecular findings.We report a case of PEComa arising in the antrum of a 71-year-old female with melena.The tumor,located predominantly in the submucosa as a well delimited nodule,measured 3.0 cm in diameter and was completely resected,with no evidence of the disease elsewhere.Histologically,it was composed predominantly of eosinophilic epithelioid cells arranged in small nests commonly related to variably sized vessels,with abundant extracellular material,moderate nuclear variation and discrete mitotic activity.No necrosis,angiolymphatic invasion or perineural infil-tration was seen.Tumor cells were uniformly positive for vimentin,smooth muscle actin,desmin and melan A.Although unusual,PEComa should be considered in the differential diagnosis of gastric neoplasia with characteristic epithelioid and oncocytic features and prominent vasculature.

Hepatic perivascular epithelioid cell tumor:A case report

BACKGROUND Perivascular epithelioid cell tumor(PEComa)is a mesenchymal tumor with histologic and immunophenotypic characteristics of perivascular epithelioid cells,has a low incidence,and can involve multiple organs.PEComa originating in the liver is extremely rare,with most cases being benign,and only a few cases are malignant.Good outcomes are achieved with radical surgical resection,but there is no effective treatment for some large tumors and specific locations that are contraindicated for surgery.CASE SUMMARY A 32-year-old woman was admitted to our hospital with a palpable abdominal mass and progressive deterioration since the previous month.An ultrasoundguided percutaneous liver aspiration biopsy was performed.Postoperative pathological immunohistochemical staining was HMB45,Melan-A,and smooth muscle actin positive.Perivascular epithelioid tumor was diagnosed.The tumor was large and could not be completely resected by surgery.Further digital subtraction angiography revealed a rich tumor blood supply,and interventional embolization followed by surgery was recommended.Finally,the patient underwent transarterial embolization(TAE)combined with sorafenib for four cycles.Angiography reexamination indicated no clear vascular staining of the tumor,and the tumor had shrunk.The patient was followed up for a short period of time,achieved a stable condition,and surgery was recommended.CONCLUSION Adjuvant combination treatment with TAE and sorafenib is safe and feasible as it shrinks the tumor preoperatively and facilitates surgery.

Perivascular epithelioid cell tumor of male pelvic cavity:a case report and literature review

Perivascular epithelioid cell tumors （PEComas） are a family of rare mesenchymal neoplasms. The PEComas, composed of epithelioid and spindle cells, have the same cellular and immtmohistocherrtical features but are found in different visceral and soft tissue sites. Here, we report the histological and immunohistochemical features of one case of PEComa restricted in the pelvic visceral peritoneum of a male patient. The patient was treated with radical surgery, and was well and on follow-up visits without tumor recurrence.

TFE3-expressing malignant perivascular epithelioid cell tumor of the mesentery:A case report and review of literature

BACKGROUND Perivascular epithelioid cell tumor(PEComa)is a rare mesenchymal tumor that exhibits an epithelioid and spindle cell morphology.The tumor is characterized by immunoreactivity for melanocytic and myogenic markers but can be misdiagnosed as more common tumors with similar characteristics,including gastrointestinal stroma tumors or leiomyosarcomas.Recently,a subset of PEComas has been reported to harbor a transcription factor binding to TFE3 fusion.Herein,we report a rare case of TFE3-expressing malignant PEComa arising from the mesentery.CASE SUMMARY A 50-year-old woman presented with abdominal discomfort for 3 months.Results of laboratory tests were all within the normal ranges,and the patient had no notable medical history.Magnetic resonance imaging revealed a large tumor on the right side of the pelvic floor,which was originally suspected to be a primary ovarian tumor.However,during surgery,the tumor was revealed to have originated from the mesentery.Histologically,the tumor was composed of bundles of spindle cells and sheets of epithelioid cells.Extensive coagulative necrosis and numerous mitotic figures were observed.Immunohistochemistry revealed that the tumor cells were positive for smooth muscle actin,HMB-45,and TFE3 expression.Tumor involvement of the rectal serosa was identified,leading to a final diagnosis of malignant PEComa of the mesentery.Surgical resection was followed by adjuvant chemotherapy.No recurrence or metastasis was observed over a 6-month follow-up period.CONCLUSION Malignant PEComa of the mesentery is extremely rare and should be distinguished from morphological mimics through differential diagnosis and immunohistochemistry.

Pediatric case of colonic perivascular epithelioid cell tumor complicated with intussusception and anal incarceration:A case report

BACKGROUND Perivascular epithelioid cell tumor(PEComa)represents a group of rare mesenchymal tumors.PEComa can occur in many organs but is rare in the colorectum,especially in children.Furthermore,PEComa is a rare cause of intussusception,the telescoping of a segment of the gastrointestinal tract into an adjacent one.We describe a rare case of pediatric PEComa complicated with intussusception and anal incarceration,and conduct a review of the current literature.CASE SUMMARY A 12-year-old girl presented with abdominal pain and abdominal ultrasound suggested intussusception.Endoscopic direct-vision intussusception treatment and colonoscopy was performed.A spherical tumor was discovered in the transverse colon and removed by surgery.Postoperative pathologic analyses revealed that the tumor volume was 5.0 cm×4.5 cm×3.0 cm and the tumor tissue was located in the submucosa of the colon,arranged in an alveolar pattern.The cell morphology was regular,no neoplastic necrosis was observed,and nuclear fission was rare.The immunohistochemical staining results were as follows:Human melanoma black 45(HMB 45)(+),cluster of differentiation 31(CD31)(+),cytokeratin(-),melanoma-associated antigen recognized by T cells(-),smooth muscle actin(-),molleya(-),desmin(-),S-100(-),CD117(-),and Ki67(positive rate in hot spot<5%).Combined with the results of pathology and immunohistochemistry,we diagnosed the tumor as PEComa.Postoperative recovery was good at the 4 mo follow-up.CONCLUSION The diagnosis of PEComa mainly depends on pathology and immunohistochemistry.Radical resection is the preferred treatment method.

Perivascular epithelioid cell tumor of the cecum： a case report and review of literatures

Perivascular epithelioid cell tumors （PEComas） are a group of rare mesenchymal neoplasms which composed of histologically and immunohistochemically distinctive perivascular epithelioid cells （PECs）. In recent years, PEComas have been manily reported in liver, kidney, lung, uterus and adnexa,1 but rare in small or large intestine.2-6 Here, we describe a case of PEComa restricted in the cecal mucosa, which displayed histological characteristics of epithelioid clear cells.

Utility of transbronchial biopsy in the diagnosis of lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis(LAM)is a rare cystic lung disease that targets women during their reproductive years.A confident diagnosis can often be based on clinical grounds,but diagnostic certainty requires pathological analysis.Although surgical lung biopsy is considered the gold standard for obtaining tissue in patients with diffuse lung disease,it is also associated with higher morbidity and mortality than alternative,less invasive techniques.The objective of our study was to examine the utility of transbronchial biopsy in the diagnosis of LAM.We conducted two online surveys of over 1000 LAM patients registered with the LAM Foundation who were accessible by email.Transbronchial biopsy specimens were subsequently collected and reviewed by an expert pathologist to validate the diagnosis.We found that transbronchial biopsy has a yield of approximately 60% in patients with LAM.We conclude that transbronchial biopsy may be a safe and effective method for establishing the diagnosis of LAM,obviating the need for surgical lung biopsy in more than half of LAM patients.