Cell Proliferation ; Cytoplasm ; metabolism ; Female ; Giant Cells ; pathology ; Humans ; Hysterectomy ; Immunophenotyping ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms ; diagnosis ; Salpingectomy ; Uterine Neoplasms ; diagnosis

Perivascular epithelioid cell tumors (PEComas) are unusual mesenchymal neoplasms composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Although PEComas have the potential to behave in a malignant fashion, malignant PEComas arising from the retroperitoneum are extremely rare. A 68-year-old woman presented with a painful palpable mass in her left upper abdomen. Computed tomography of the abdomen showed a 9 cm sized heterogeneous mass in left para-aortic space and multiple hypervascular nodules in the liver. 18F-fludeoxyglucose-PET/CT showed multifocal hypermetabolic lesions in retroperitoneum, liver, and skeletal bones. Percutaneous needle biopsies were done on the retroperitoneal and hepatic mass. Both specimens were positive for human melanoma black-45 (HMB-45) on histological and immunohistochemical staining which was compatible with PEComas. Herein, we report a rare case of retroperitoneal PEComa with multiple metastases involving liver and bone at initial diagnosis that exhibited aggressive behavior and resulted in a devastating prognosis.
Aged ; Bone Neoplasms/pathology/radiography/secondary ; Female ; Fluorodeoxyglucose F18 ; Humans ; Liver Neoplasms/pathology/radiography/secondary ; Perivascular Epithelioid Cell Neoplasms/*diagnosis/pathology ; Positron-Emission Tomography ; Tomography, X-Ray Computed

Adolescent ; Carcinoma, Renal Cell ; metabolism ; pathology ; Desmin ; metabolism ; Diagnosis, Differential ; Humans ; Leg ; MART-1 Antigen ; metabolism ; Male ; Melanoma ; metabolism ; pathology ; Melanoma-Specific Antigens ; metabolism ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; surgery ; Sarcoma, Clear Cell ; metabolism ; pathology ; Skin Neoplasms ; metabolism ; pathology ; surgery

Actins ; metabolism ; Adult ; Diagnosis, Differential ; Endometrial Neoplasms ; metabolism ; pathology ; surgery ; Endometrial Stromal Tumors ; metabolism ; pathology ; surgery ; Female ; Humans ; Hysterectomy ; Leiomyoma, Epithelioid ; metabolism ; pathology ; Melanoma-Specific Antigens ; metabolism ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; surgery ; Receptors, Progesterone ; metabolism ; Sarcoma, Clear Cell ; metabolism ; pathology ; Uterine Neoplasms ; metabolism ; pathology ; surgery

Actins ; metabolism ; Angiomyoma ; metabolism ; pathology ; surgery ; Cranial Fossa, Middle ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Male ; Melanoma-Specific Antigens ; metabolism ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms ; immunology ; S100 Proteins ; metabolism ; Skull Base Neoplasms ; metabolism ; pathology ; surgery

Perivascular epithelioid cell tumor (PEComa) is extremely rare, which originated from mesenchymal cells in the intestine, and composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. We report here on a case of PEComa in the sigmoid colon. A 62-year-old woman presented with hematochzia 10 days ago. Her abdominal computed tomography scan showed a 5 cm sized intraluminal fungating heterogeneously enhanced, high density mass, which infiltrated pericolic tissue surrounding the sigmoid colon. Colonoscopy showed a purple colored polypoid mass with lobulating contour in the sigmoid colon. She underwent laparoscopic anterior resection. On the histologic examination, the tumor consisted of polygonal epithelioid cells with sheet-like growth of nests, which looked like alveolar tissues in lung. The tumor cells were strongly positive stained with human melanoma black-45 (HMB-45). Pathologic examination was compatible with PEComa. Sixteen months after surgery, she did well without tumor recurrence after surgery. We review the literatures concerning PEComa of the intestine focusing on endoscopic findings.
Colonic Neoplasms/diagnosis ; Colonoscopy ; Female ; Gastrointestinal Hemorrhage ; Humans ; Melanoma-Specific Antigens/metabolism ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms/*diagnosis/pathology/surgery ; Tomography, X-Ray Computed

Actins ; metabolism ; Adenocarcinoma, Clear Cell ; metabolism ; pathology ; Adult ; Carcinoma, Renal Cell ; metabolism ; pathology ; Desmin ; metabolism ; Diagnosis, Differential ; Endometrial Stromal Tumors ; metabolism ; pathology ; Female ; Follow-Up Studies ; Humans ; Hysterectomy ; Leiomyoma, Epithelioid ; metabolism ; pathology ; Melanoma ; metabolism ; pathology ; Melanoma-Specific Antigens ; metabolism ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; surgery ; Receptors, Progesterone ; metabolism ; Uterine Neoplasms ; metabolism ; pathology ; surgery ; Vimentin ; metabolism

OBJECTIVETo study the clinicopathologic features and differential diagnosis of perivascular epithelioid cell tumors (PEComas) occurring in the urinary system.

METHODSThe clinicopathologic features of 21 cases of PEComa from September 2002 to September 2010 occurring in the urinary system were retrospectively reviewed. Immunohistochemical study for HMB 45, S-100 protein, smooth muscle actin, desmin, Melan A and Ki-67 was carried out.

RESULTSAmongst the 21 cases studied, there were 5 males and 16 females. The age of patients ranged from 16 to 76 years (median = 51.3 years). Twenty cases occurred in the kidney and 1 in the bladder. The predominant histopathologic subtype of renal PEComas was classic type (10/20), followed by epithelioid type (5/20), smooth muscle type (3/20), inflammatory type (1/20) and sclerosing type (1/20). Immunohistochemical study showed that HMB 45 and smooth muscle actin were positive in 95.2% (20/21) and 80.9% (17/21) cases, respectively. Melan A, desmin and S-100 protein were expressed in 71.4% (15/21), 61.9% (13/21) and 33.3% (7/21) cases, respectively. The mean proliferative index was 1.29% (range = 0 to 5%). HMB 45 and Melan A were expressed in all of the 5 cases of epithelioid PEComas, whereas smooth muscle actin and desmin were only expressed in one of them. There was no significant difference between epithelioid PEComas and non-epithelioid PEComas in the expression of HMB 45, Melan A, smooth muscle actin and desmin. Positive staining for HMB 45 and smooth muscle actin was demonstrated in the case of bladder PEComa.

CONCLUSIONSPEComas of the urinary system predominantly affect the kidney. Epithelioid renal PEComas and bladder PEComa are relatively rare and have unique pathologic features. It is necessary to distinguish PEComas from other malignant tumors. Immunohistochemical study for HMB 45, Melan A and smooth muscle actin is helpful for confirmation of diagnosis.

Actins ; metabolism ; Adolescent ; Adult ; Aged ; Carcinoma, Renal Cell ; metabolism ; pathology ; Desmin ; metabolism ; Diagnosis, Differential ; Female ; Gastrointestinal Stromal Tumors ; metabolism ; pathology ; Humans ; Immunohistochemistry ; Kidney Neoplasms ; metabolism ; pathology ; Leiomyosarcoma ; metabolism ; pathology ; MART-1 Antigen ; metabolism ; Male ; Melanoma ; metabolism ; pathology ; Melanoma-Specific Antigens ; metabolism ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; S100 Proteins ; metabolism ; Urinary Bladder Neoplasms ; metabolism ; pathology ; Young Adult

Actins ; metabolism ; Angiomyolipoma ; metabolism ; pathology ; surgery ; Desmin ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; S100 Proteins ; metabolism ; Skin Neoplasms ; metabolism ; pathology ; surgery

Actins ; metabolism ; Angiomyolipoma ; pathology ; Carcinoma, Renal Cell ; pathology ; Diagnosis, Differential ; Epithelioid Cells ; metabolism ; pathology ; Female ; Gastrointestinal Neoplasms ; pathology ; Gastrointestinal Stromal Tumors ; pathology ; Humans ; Kidney Neoplasms ; metabolism ; pathology ; Lung Neoplasms ; pathology ; Lymphangioleiomyomatosis ; pathology ; Male ; Melanoma ; pathology ; Melanoma-Specific Antigens ; metabolism ; Pancreatic Neoplasms ; pathology ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; Sarcoma, Clear Cell ; pathology ; Skin Neoplasms ; pathology ; Uterine Neoplasms ; pathology