S100 proteins and their implication in the thalamus: an integrative review / Las proteínas S100 y su implicación en el tálamo: una revisión integradora

SUMMARY: S100 proteins belong group of calcium-binding proteins and are present in physiological intracellular and extracellular regulatory activities, such as cell differentiation, and act in inflammatory and neoplastic pathological processes. Recently, its expressions in the nervous system have been extensively studied, seeking to elucidate its action at the level of the thalamus: A structure of the central nervous system that is part of important circuits, such as somatosensory, behavioral, memory and cognitive, as well as being responsible for the transmission and regulation of information to the cerebral cortex. This article is an integrative review of scientific literature, which analyzed 12 studies present in Pubmed. The analysis showed that the relationship of S100 proteins and the thalamus has been described in neoplastic processes, mental disorders, hypoxia, trauma, stress, infection, Parkinson's disease and epilepsy. In summary, it is possible to conclude that this protein family is relevant as a marker in processes of thalamic injury, requiring further studies to better understand its clinical, preclinical meanings and its prognostic value.

Las proteínas S100 pertenecen al grupo de proteínas fijadoras de calcio y están presentes en actividades reguladoras fisiológicas intracelulares y extracelulares, como la diferenciación celular, y actúan en procesos patológicos inflamatorios y neoplásicos. Recientemente, sus expresiones en el sistema nervioso han sido ampliamente estudiadas, buscando dilucidar su acción a nivel del tálamo: una estructura del sistema nervioso central que forma parte de importantes circuitos, como el somatosensorial, conductual, de memoria y cognitivo, así como además de ser responsable de la transmisión y regulación de la información a la corteza cerebral. Este artículo es una revisión integradora de la literatura científica, que analizó 12 estudios presentes en Pubmed. El análisis mostró que la relación de las proteínas S100 y el tálamo ha sido descrita en procesos neoplásicos, trastornos mentales, hipoxia, trauma, estrés, infección, enfermedad de Parkinson y epilepsia. En resumen, es posible concluir que esta familia de proteínas es relevante como marcador en procesos de lesión talámica, requiriendo más estudios para comprender mejor su significado clínico, preclínico y su valor pronóstico.

Function of s100 protein in coronary atherosclerosis / Función de la proteína s100 en aterosclerosis coronaria

SUMMARY: Atherosclerosis is a complex disease whose pathogenesis includes endothelial activation, accumulation of lipids in the subendothelium, formation of foam cells, fat bands and formation of atherosclerotic plaque. These complex mechanisms involve different cell populations in the intimate sub-endothelium, and the S-100 protein family plays a role in a number of extracellular and intracellular processes during the development of atherosclerotic lesions. The aim of this study was to determine the phenotypic characteristics of smooth muscle cells and the consequent expression of S100 protein in atherosclerotic altered coronary arteries in advanced stages of atherosclerosis. 19 samples of right atherosclerotic coronary arteries in stages of fibro atheroma (type V lesion) and complicated lesions (type VI lesion) have been analyzed. According to the standard protocol, the following primary antibodies have been used in the immunohistochemical analysis: a-smooth muscle actin (α-SMA), vimentin and S-100 protein. All analyzed samples have been in advanced stages of atherosclerosis, fibro atheroma (stage V lesions) and complicated lesions (type VI lesions). Most of them have had the structure of a complicated lesion with atheroma or fibro atheroma as a basis, subsequently complicated by disruption (subtype VI a), hemorrhage (subtype VI b) or thrombosis (subtype VI c), as well as by the presence of several complications on the same sample. Marked hypocellularity is present in the subendothelium of plaques. Cell population at plaque margins is characterized by immunoreactivity to α-SMA, vimentin, and S100 protein. Some of these cells accumulate lipids and look like foam cells. In the cell population at the margins of the plaques, smooth muscle cells of the synthetic phenotype are present, some of which accumulate lipids and demonstrate S100 immunoreactivity. Summarizing numerous literature data and our results, we could assume that smooth muscle cells, due to their synthetic and proliferative activity in the earlier stages of pathogenesis, as well as the consequent expression of S100 protein, could accumulate lipids in the earlier stages of atherosclerosis which, in advanced stages analyzed in this study, result in immunoreactivity of foam cells of smooth muscle origin to S100 protein.

RESUMEN: La aterosclerosis es una enfermedad compleja cuya patogenia incluye activación endotelial, acumulación de lípidos en el subendotelio, formación de células espumosas, bandas grasas y formación de placa aterosclerótica. Estos complejos mecanismos involucran diferentes poblaciones celulares en el subendotelio íntimo, y la familia de proteínas S-100 juega un papel en varios procesos extracelulares e intracelulares durante el desarrollo de lesiones ateroscleróticas. El objetivo de este estudio fue determinar las características fenotípicas de las células de músculo liso y la consecuente expresión de la proteína S100 en arterias coronarias alteradas ateroscleróticas en estadios avanzados de aterosclerosis. Se analizaron 19 muestras de arterias coronarias ateroscleróticas derechas en estadios de fibroateroma (lesión tipo V) y lesiones complicadas (lesión tipo VI). Según el protocolo estándar, en el análisis inmunohistoquímico se utilizaron los siguientes anticuerpos primarios: α-actina de músculo liso (α-SMA), vimentina y proteína S-100. Todas las muestras analizadas han estado en estadios avanzados de aterosclerosis, fibroateroma (lesiones estadio V) y lesiones complicadas (lesiones tipo VI). La mayoría de ellos han tenido la estructura de una lesión complicada con ateroma o fibroateroma como base, complicada posteriormente por disrupción (subtipo VI a), hemorragia (subtipo VI b) o trombosis (subtipo VI c), así como por la presencia de varias complicaciones en la misma muestra. La hipocelularidad marcada estaba presente en el subendotelio de las placas. La población celular en los márgenes de la placa se caracterizaba por inmunorreactividad a α-SMA, vimentina y proteína S100. Algunas de estas células acumulan lípidos y parecen células espumosas. En la población celular en los márgenes de las placas, estaban presentes las células de músculo liso de fenotipo sintético, algunas de las cuales acumulaban lípidos y mostraban inmunorreactividad S100. Resumiendo numerosos datos de la literatura y nuestros resultados, podríamos suponer que las células del músculo liso, debido a su actividad sintética y proliferativa en las primeras etapas de la patogénesis, así como la consecuente expresión de la proteína S100, podrían acumular lípidos en las primeras etapas de la aterosclerosis que, en estadios avanzados analizados en este estudio, dan como resultado inmunorreactividad de células espumosas de origen muscular liso a la proteína S100.

Histological variability and the importance of clinicopathological correlation in cutaneous Rosai-Dorfman disease

Abstract: Rosai-Dorfman disease is a benign histiocytic proliferative disorder of unknown etiology. The disease mainly affects lymph node tissue, although it is rarely confined to the skin. Here, we describe a 53-year-old woman with purely cutaneous Rosai-Dorfman disease. The patient presented with a large pigmented plaque on her left leg, and sparse erythematous papules on her face and arms. A complete clinical response was achieved with thalidomide, followed by recurrence at the initial site one year later. The histological examination displayed the typical features of Rosai-Dorfman disease in the recent lesions but not in the older lesions. In the setting of no lymphadenopathy, the histopathological features of Rosai-Dorfman disease are commonly misinterpreted. Therefore, awareness of the histological aspects present at different stages, not always featuring the hallmark microscopic signs of Rosai-Dorfman disease, is particularly important for a correct diagnosis of this rare disorder.

Evaluación de reactividad inmunohistoquímica con método del Complejo Avidina­Biotina (ABC) / Evaluation of immunohistochemical reactivity with Avidin-Biotin Complex (ABC) method

Inmunohistoquímica es toda técnica que permite detectar in situ componentes celulares y extracelulares por medio de anticuerpos específicos, empleando sistemas de detección enzimáticos. Dentro de los métodos inmunohistoquímicos, la técnica del complejo avidina­biotina(ABC) es ampliamente utilizada debido a su alta sensibilidad. El objetivo del presente estudio fueevaluar la reactividad inmunohistoquímica del anticuerpo 4C4.9 para la detección de la proteínaS-100, utilizando el método ABC. Para la evaluación de la reactividad inmunohistoquímica se utilizaron 2 biopsias de piel humana con diagnóstico histopatológico de melanoma maligno nodular ulcerado y nevus melanocítico intradérmico, provenientes del Laboratorio de Investigación en Biotecnología Animal de la Universidad de La Frontera, Temuco, Chile. Se utilizó el Kit VECTASTAIN®como método de detección, la dilución del anticuerpo 4C4.9 fue 1/250 y la temperatura de incubación fue a 4 ºC ó 37 ºC por 18 horas. Para validar la técnica, se realizó un control positivo y otro negativo para 4C4.9. Los resultados de la tinción inmunohistoquímica por el método del complejo ABC mostraron tinción positiva para la proteína S-100, tanto en melanoma maligno nodular ulcerado, como en nevus melanocítico intradérmico, incubados durante 18 horas a 4 ºC ó 37 ºC. Sin embargo, la inmunotinción fue más intensa cuando el anticuerpo primario se incubó a 37 ºC. Para una correcta interpretación de los resultados, es necesario tener en consideración que la reacción antígeno-anticuerpo se ve influenciada por diversos factores, como la concentración del anticuerpo, el tiempo y la temperatura de incubación. En conclusión, nuestros resultados sugieren incubarlas muestras con el primer anticuerpo (4C4.9) en una dilución de 1/250 en agua destilada, incu-bando durante 18 h a 37 ºC. Se recomienda la utilización del anticuerpo 4C4.9 como apoyo al diagnóstico y diagnóstico diferencial.

Immunohistochemistry is anytechnique that can detect cellular and extracellular components in situ by means of specific antibodies,using enzymatic detection systems. Among immunohistochemical methods, the technique ofavidin - biotin complex (ABC) is widely used because of its high sensitivity. The aim of this study was to evaluate the immunohistochemical reactivity of the4C4.9 antibody for detection of S-100 protein using the ABC method. For the evaluation ofimmunohistochemical reactivity 2 biopsies of humanskin were used with histopathological diagnosis ofulcerated malignant melanoma and melanocyticintradermal nevi from the Research Laboratory onAnimal Biotechnology of the Universidad de La Fron-tera, Chile. The Kit VECTASTAIN® was used asdetection method, the dilution the 4C4.9 antibodywas 1/250 and incubation temperature was at 4 °Cor 37 °C for 18 hours. To validate the technique, apositive control and a negative for 4C4.9 was performed. The results of immunohistochemicalstaining by the method of ABC complex showed positive staining for protein S-100 both in ulcerated malignant melanoma and melanocytic intradermalnevi, incubated for 18 hours at 4 °C or 37 °C.However, immunostaining was more intense when the primary antibody was incubated at 37° C. For acorrect interpretation of the results, it is necessary to take into consideration that the antigen-antibody reaction is influenced by various factors such as the concentration of antibody, time and temperature ofincubation. In conclusion, our results suggest incubating the samples with the first antibody (4C4.9)at 1/250 dilution in distilled water, incubating for 18h at 37 ºC. However, immunostaining was moreintense when the primary antibody was incubated at37° C. For a correct interpretation of the results, it isnecessary to take into consideration that antigen-antibody reaction is influenced by various factors suchas the concentration of antibody, time and temperature of incubation. In conclusion, our results suggest incubating the samples with the first antibody(4C4.9) at 1/250 dilution in distilled water, incubating for 18 h at 37 ºC. The use of the antibody 4C4.9 is recommended to support the diagnosis and differential diagnosis.

Diffuse Ganglioneuromatosis of the Colon Presenting as a Large Subepithelial Tumor in Adults: Report of Two Cases / 대한소화기학회지

Colonic diffuse ganglioneuromatosis is a benign neoplastic condition characterized by disseminated, intramural, or transmural proliferation of neural elements involving the enteric plexuses, sometimes associated with von Recklinghausen's disease and other multiple tumor syndromes. Colonic diffuse ganglioneuromatosis is usually large, ranging from 1 to 17 cm, and thus can distort the surrounding tissue architecture as well as infiltrate the adjacent bowel wall. However, colonic diffuse ganglioneuromatosis is an exceptional finding in adults and only individual cases are reported in the literature. Herein, we report two unusual cases of adult patients with colonic diffuse transmural ganglioneuromatosis presenting as a large subepithelial tumor.

Differential Expression of E-Cadherin, beta-Catenin, and S100A4 in Intestinal Type and Nonintestinal Type Ampulla of Vater Cancers

BACKGROUND/AIMS: Epithelial-mesenchymal transition (EMT)-related proteins may exhibit differential expression in intestinal type or pancreatobiliary type ampulla of Vater carcinomas (AVCs). We evaluated the expression of E-cadherin, beta-catenin, and S100A4 in intestinal and nonintestinal type AVCs and analyzed their relationships with clinicopathological variables and survival. METHODS: A clinicopathological review of 105 patients with AVCs and immunohistochemical staining for E-cadherin, beta-catenin, and S100A4 were performed. The association between clinicopathological parameters, histological type, and expression of EMT proteins and their effects on survival were analyzed. RESULTS: Sixty-five intestinal type, 35 pancreatobiliary type, and five other types of AVCs were identified. The severity of EMT changes differed between the AVC types; membranous loss of E-cadherin and beta-catenin was observed in nonintestinal type tumors, whereas aberrant nonmembranous beta-catenin expression was observed in intestinal type tumors. EMT-related changes were more pronounced in the invasive tumor margin than in the tumor center, and these EMT-related changes were related to tumor aggressiveness. Among the clinicopathological parameters, a desmoplastic reaction was related to overall survival, and the reaction was more severe in nonintestinal type than in intestinal type AVCs. CONCLUSIONS: Dysregulation of E-cadherin, beta-cadherin, and S100A4 expression may play a role in the carcinogenesis and tumor progression of AVCs.

Endoscopic Resection as a Possible Radical Treatment for Duodenal Gangliocytic Paraganglioma: A Report of Four Cases / 대한소화기학회지

Gangliocytic paraganglioma (GP) is a rare, benign tumor which is usually found in the duodenum. We here report four recent cases of GP, with successful endoscopic resection in three cases, including a lesion on the ampulla of Vater. In all cases, each lesion had a stalk that facilitated removal using an endoscopic approach. Endoscopic mucosal resection is a feasible and safe treatment if the location, depth, and lymph node status are all favorable and is also helpful for definite diagnosis of unknown duodenal mass. To avoid morbidity resulting from open surgical resection, careful inspection for the peduncle of the GP will help determine the feasibility of endoscopic resection.

A Case of Metachronous Development of Esophageal Squamous Cell Carcinoma in the Patient with Esophageal Carcinosarcoma / 대한소화기학회지

Esophageal carcinosarcoma is a rare malignant esophageal neoplasm consisting of both carcinomatous and sarcomatous elements, with an incidence of 0.5%. There have been only a few case reports of carcinosarcoma and squamous cell carcinoma coexisting in the esophagus. However, all of these are cases of synchronous or metachronous development of carcinosarcoma after chemoradiotherapy in patients of esophageal squamous cell carcinoma. A 53-year-old man underwent esophagogastroduodenoscopy because of chest pain for several months. Endoscopic examination revealed a huge pedunculated esophageal polypoid mass. Endoscopic submucosal dissection (ESD) was performed and histopathologic examination confirmed spindle cell carcinoma (carcinosarcoma). He refused additional esophagectomy. After 21 months, third follow-up endoscopy showed poorly-demarcated flat, faint discolored lesions at different location from the previous ESD site and endoscopic biopsies confirmed squamous cell carcinoma. To the best of our knowledge, this is the first case of metachronous development of esophageal squamous cell carcinoma in a patient with esophageal carcinosarcoma.

A Case of Low-grade Fibromyxoid Sarcoma of the Colon / 대한소화기학회지

Low-grade fibromyxoid sarcoma is a slowly growing soft tissue neoplasm that shows benign histologic features but may have clinical course of malignant disease. It has been reported to occur in the thigh, inguinal area, axilla, shoulder, neck, perineum or buttock. However, there have been few cases of abdominal organ involvement. A 21-year-old woman presented with a large palpable abdominal mass. A 7x4 cm sized round soft tissue tumor at right upper quadrant area was identified by abdominopelvic CT scan. Percutaneous ultrasound-guided biopsy revealed features of spindle cell tumor. On exploration, the tumor originated from transvers colon and was attached to gastrocolic ligament, transverse mesocolon and stomach. The tumor could be dissected with transverse colectomy and partial gastrectomy. The excised tumor, measuring 7x5x5 cm, was well demarcated and appeared as an ovoid mass with firm and myxoid cut surface. She was diagnosed with low-grade fibromyxoid sarcoma arising from transverse colon, and is currently being followed-up without recurrence or metastasis.

Case for diagnosis / Caso para diagnostico

Granular cell tumor is a rare benign neoplasm of neural origin. We report the case of a female patient, 27 years old presenting a brown-red nodule in the right arm, which pathological examination showed to be formed by polygonal cells with eosinophilic granular cytoplasm and immunohistochemistry positive for S100 protein and CD68. Granular cell tumor is usually solitary and in half the cases located in the head and neck areas, 30% of these in the tongue. It is most frequent between the third and fifth decades of life in women and people of African-American ethnicity. Its origination is controversial, including the possible origins in muscle, fibroblasts, neural crest, neural sheath or histiocytes. The positivity for S-100 and CD68 suggest the neural origin.

O tumor de células granulares é uma neoplasia benigna rara, de origem neural. Relatamos caso de paciente feminina, 27 anos, com nódulo de superfície acastanhada no braço direito, cujo exame anatomopatológico evidenciou densa proliferação de células, com amplo citoplasma contendo grânulos eosinofílicos, e imuno-histoquímica positiva para proteínas S100 e CD68. O tumor de células granulares é geralmente solitário e, em metade dos casos, localiza-se em cabeça e pescoço, dos quais 23% na língua. É mais frequente entre a terceira e a quinta décadas de vida, em mulheres e pessoas de etnia negra. A positividade para S-100 e CD68 favorece origem neural.

Correlation of Immunohistochemical Markers and BRAF Mutation Status with Histological Variants of Papillary Thyroid Carcinoma in the Korean Population

Several pathologic characteristics are associated with an adverse clinical outcome in papillary thyroid carcinoma (PTC), including the histological variant. This study aimed to investigate immunohistochemical expression and BRAF mutation status based on the histological variant and evaluated potential markers of aggressive behavior of PTC in Korean patients. In all, 407 PTC cases were classified to each histological variant, and the 94 representative cases were subjected to immunohistochemistry and BRAF mutation analysis. The classic type, follicular variant (FV) and tall cell variant (TCV) represented 76.9%, 14.2% and 6%, respectively. TCV showed a larger tumor size (P = 0.009), frequent extrathyroidal extension (P = 0.022) and cervical lymph node (LN) metastasis (P = 0.018). TCV and FV showed the reduced expression of galectin-3 (P = 0.003) and HBME1 (P = 0.114). Regardless of histology, PTEN loss and diffuse S100A4 expression were associated with LN metastasis (P = 0.007, P = 0.013). All TCVs harbored BRAF V600E mutation, and FV harbored less BRAF V600E mutation (P = 0.043). Immunohistochemical evaluation showed characteristic patterns in histological variants. PTEN and S100A4 expression are suggested as indicators of regional lymph node metastasis.

Massive retinal gliosis: An unusual case with immunohistochemical study.

Massive retinal gliosis (MRG) is a rare, benign intraocular condition that results from the proliferation of well-differentiated glial cells. Immunohistochemically, these cells show positivity for glial fibrillary acid protein (GFAP), neuron specific enolase (NSE), and S-100 protein. We encountered a case of a 45-year-old female with loss of vision in the left eye. She had a history of trauma to that eye two years ago. Enucleation was carried out, because malignancy was suspected due to retinal calcification. On the basis of light microscopy and immunohistochemistry (IHC) performed on the enucleated eye, it was diagnosed as massive retinal gliosis.

Spinal Cord Injury Markedly Altered Protein Expression Patterns in the Affected Rat Urinary Bladder during Healing Stages

The influence of spinal cord injury (SCI) on protein expression in the rat urinary bladder was assessed by proteomic analysis at different time intervals post-injury. After contusion SCI between T9 and T10, bladder tissues were processed by 2-DE and MALDI-TOF/MS at 6 hr to 28 days after SCI to identify proteins involved in the healing process of SCI-induced neurogenic bladder. Approximately 1,000 spots from the bladder of SCI and sham groups were visualized and identified. At one day after SCI, the expression levels of three protein were increased, and seven spots were down-regulated, including heat shock protein 27 (Hsp27) and heat shock protein 20 (Hsp20). Fifteen spots such as S100-A11 were differentially expressed seven days post-injury, and seven proteins including transgelin had altered expression patterns 28 days after injury. Of the proteins with altered expression levels, transgelin, S100-A11, Hsp27 and Hsp20 were continuously and variably expressed throughout the entire post-SCI recovery of the bladder. The identified proteins at each time point belong to eight functional categories. The altered expression patterns identified by 2-DE of transgelin and S100-A11 were verified by Western blot. Transgelin and protein S100-A11 may be candidates for protein biomarkers in the bladder healing process after SCI.

Silencing of the annexin II gene down- regulates the levels of S100A10, c-Myc, and plasmin and inhibits breast cancer cell proliferation and invasion

To explore the roles of annexin II in breast cancer progression, and to study the effect of annexin II on breast cancer cell proliferation and invasion. This study was conducted in the Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, China from December 2006 to January 2009. First, we employed Western blot and reverse transcriptase polymerase chain reaction to detect the expression of annexin II and S100A10 in a panel of well-characterized human breast cancer cell lines, and investigated the localization of annexin II and S100A10 by use of immunofluorescence. We then silenced the expression of annexin II in MDA-MB-435s, which was found to over express annexin II, using the chemically-synthetic annexin II small interfering RNA [siRNA] duplexes [including 3 groups: blank MDA-MB-435s cells, cells transfected with negative control siRNA, and cells transfected with annexin II-siRNA]. Finally, the cell proliferation, invasion, and plasmin generation were assayed, and the cellular levels of S100A10 and c-Myc were also detected. All the tests were repeated 3 times. Annexin II and S100A10 were over expressed in invasive human breast cancer cell lines. The siRNA targeting annexin II of MDS-MB 435s cells did not only decrease annexin II messenger RNA and protein levels, but also down-regulated the levels of S100A10, and c-Myc. The treated cells were remarkably blocked in the G0/G1 phase, and cells in the S/G2+M phase decreased. Additionally, the treatment with siRNA resulted in reduction of plasmin generation as well as a loss of the invasive capacity of breast cancer cells. Annexin II might be a key contributor to breast cancer proliferation and invasion

Primary Rectal Malignant Melanoma with Rapid Progression after Complete Resection / 대한소화기학회지

No abstract available.

Schwannoma of the eyelid: Apropos of two cases.

Schwannoma, also referred to as neurilemmoma, is a benign tumor of peripheral nerve arising from Schwann cells that form the neural sheath. Schwannoma of ophthalmic interest is rare although it has been reported in relation with the orbit, and less frequently with the uveal tract and conjunctiva. Isolated eyelid schwannoma is extremely uncommon. Up until now, only eight cases have been reported in literature. Herein, we report two cases of eyelid schwannoma.

Sinus Histiocytosis with Massive Lymphadenopathy: A Case Report with Pleural Effusion and Cervical Lymphadenopathy

Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare disorder characterized by a nonneoplastic proliferation of distinctive histiocyte cells within lymph node sinuses and lymphatics in extranodal sites. SHML occurs worldwide and is primarily a disease of childhood and early adulthood. A 26-yr-old man presented with painless palpable lymph node in cervical area. Radiographic studies revealed pleural effusion with lymphadenopathy and calcification in mediastinum. The cervical lymph node biopsy showed dilated sinuses filled with histiocytes with clear cytoplasm. The cells stained positive with CD68 and S-100. These cytologic and immunohistochemical findings were considered consistent with the diagnosis of SHML.

Gastric Schwannoma / 대한소화기학회지

No abstract available.

Granular Cell Tumor of the Descending Colon Treated by Endoscopic Mucosal Resection: A Case Report and Review of the Literature

Although colorectal granular cell tumors (GCTs) are rare, their incidental finding has increased as the use of diagnostic colonoscopy has become more common. Here we describe the case of a 41-yr-old man with a GCT in the descending colon that was detected after a screening colonoscopy. Endoscopic examination revealed a yellowish submucosal tumor, 13x12 mm in diameter, in the descending colon. Endoscopic mucosal resection (EMR) followed by histological examination revealed that the tumor was composed of plump histiocyte-like cells with an abundant granular eosinophilic cytoplasm and small round nuclei. The tumor cells expressed S-100 protein and stained with periodic acid-Schiff, but were negative for desmin and cytokeratin. The resected tumor was diagnosed as a GCT. Colonoscopists should consider the possibility of GCT in the differential diagnosis of yellowish submucosal tumors of the colon. In such patients, EMR seems to be a feasible and safe approach for diagnosis and treatment.

Perivascular Epithelioid Cell Tumor (PEComa) of Abdominal Cavity from Falciform Ligament: A Case Report

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.