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

Clear cell tumor of the lung is a rare and very unusual benign pulmonary tumor. As clear cell tumor of the lung contains abundant cytoplasmic glycogen, this tumor is called "sugar tumor". We report a case of sugar tumor in a 64-yr-old man presenting as a round pulmonary nodule. On dynamic computed tomography (CT) scans, the solitary pulmonary nodule showed early wash-in enhancement with an early washout pattern like a lung malignancy. The patient underwent wedge resection for the tumor. Pathologic examination, including immunohistochemical studies, revealed that the nodule was a benign clear cell tumor, so-called "sugar tumor". Because only a small number of cases have been reported previously, clinical aspects, radiological characteristics on dynamic contrast-enhanced CT, and differential diagnosis of the tumor are not well established. Herein we present a clear cell tumor of the lung and discuss the clinical, radiological, and pathological features of the tumor.
Antigens, Neoplasm/metabolism ; Diagnosis, Differential ; Humans ; Lung/radiography/surgery ; Lung Neoplasms/diagnosis/pathology/*radiography ; Male ; Middle Aged ; Neoplasm Proteins/metabolism ; Perivascular Epithelioid Cell Neoplasms/diagnosis/pathology/*radiography ; Solitary Pulmonary Nodule/diagnosis/pathology/*radiography ; *Tomography, X-Ray Computed

We present a case of perivascular epithelioid cell tumors (PEComas) in the abdominal cavity at the falciform ligament. A 30-yr-old Korean man visited to hospital for the evaluation of a growing, palpable abdominal mass. He had felt the mass growing over 6 months. There was no family or personal history of tuberous sclerosis. The resected specimen showed a mass of 8.0x7.0x5.5 cm in size. Histological examination showed sheets of spindle-to-epithelioid cells with clear-to-eosinophilic cytoplasm. Immunohistochemically, tumor cells were positive for HMB-4 (gp100) and smooth muscle actin. They were also positive for the S-100, which is a marker of neurogenic and melanocytic tumors. Patient was treated with radical resection of tumor without any adjuvant therapy. He is well and on follow-up visits without tumor recurrence.
Abdominal Neoplasms/*diagnosis/pathology/surgery ; Actins/metabolism ; Adult ; Antigens, Neoplasm/metabolism ; Humans ; *Ligaments/pathology ; Male ; Neoplasm Proteins/metabolism ; Perivascular Epithelioid Cell Neoplasms/*diagnosis/pathology/surgery ; S100 Proteins/metabolism ; Tomography, X-Ray Computed

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 ; 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

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 pathologic features, diagnosis, differential diagnosis and biologic behavior of uterine perivascular epithelioid tumor.

METHODSFive cases of uterine perivascular epithelioid cell tumor were studied by light microscopy and immunohistochemistry. Follow-up information was reviewed.

RESULTSAll the five tumors were composed by clear or eosinophilic cells arranged in nests and cords, associated with abundant small vessels and hyalinization in the stroma. Immunohistochemically, the tumor cells demonstrated positive staining for melanocytic markers (HMB45 and/or Melan-A), desmin and smooth muscle actin. The staining for cytokeratin and CD10 was negative. All the patients followed for a certain period are still alive, with no evidence of disease recurrence.

CONCLUSIONSPerivascular epithelioid cell tumor is a rare mesenchymal tumor of uterus, with distinctive histologic and immunohistochemical features. It should be distinguished from clear cell carcinoma and epithelioid leiomyoma of uterus. Positivity for melanocytic markers (especially HMB45) plays an important role in the diagnosis of this tumor. In general, the tumor is categorized as benign, with uncertain malignant potential and malignant.

Adenocarcinoma, Clear Cell ; pathology ; Adult ; Antigens, Neoplasm ; metabolism ; Desmin ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Hysterectomy ; methods ; Immunohistochemistry ; Leiomyoma, Epithelioid ; pathology ; Melanoma-Specific Antigens ; Middle Aged ; Neoplasm Proteins ; metabolism ; Perivascular Epithelioid Cell Neoplasms ; metabolism ; pathology ; surgery ; Uterine Neoplasms ; metabolism ; pathology ; surgery

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