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Brian P Rubin - One of the best experts on this subject based on the ideXlab platform.
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Can MDM2 analytical tests performed on core needle biopsy be relied upon to diagnose Well-Differentiated Liposarcoma?
Modern Pathology, 2010Co-Authors: Joshua Weaver, Priya Rao, John R Goldblum, Michael J Joyce, Sondra L Turner, Alexander Jf Lazar, Dolores López-terada, Raymond R Tubbs, Brian P RubinAbstract:Well-Differentiated Liposarcoma/atypical lipomatous tumor can be difficult to differentiate from benign lipomatous tumors, especially on limited biopsy material. Adjunctive tests for MDM2 (murine double minute 2) have proven useful in whole-tissue sections; however, their utility has not been determined within the increasingly popular core needle biopsy. Herein, we compare the ability of MDM2 immunohistochemistry and MDM2 fluorescence in situ hybridization (FISH) to discriminate benign lipomatous tumors from Well-Differentiated Liposarcoma on core needle biopsies. Well-Differentiated Liposarcoma ( n =17) and an assortment of benign lipomatous tumors ( n =37), which had concurrent or previous core needle biopsies, and resection specimens were subjected to both MDM2 immunohistochemistry and MDM2 FISH on both whole-tissue sections and corresponding core needle biopsy sections. Percentage tumor cells positive for MDM2 by immunohistochemistry and an MDM2: CEP12 FISH ratio was calculated in each biopsy and resection specimen pair and the results were compared. MDM2 FISH had a higher sensitivity (100%) and specificity (100%) compared with MDM2 immunohistochemistry (65 and 89%) in core needle biopsies, respectively. In addition, MDM2 immunohistochemistry had a false-positive rate of 11%, compared to 0% with FISH. The average MDM2: CEP12 ratio was similar in the biopsy material compared with the whole-tissue sections in both Well-Differentiated Liposarcoma and the benign lipomatous tumor group of neoplasms. Detection of MDM2 amplification by FISH is a more sensitive and specific adjunctive test than MDM2 immunohistochemistry to differentiate Well-Differentiated Liposarcoma from various benign lipomatous tumors, especially on limited tissue samples.
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Pseudosarcomatous fibroblastic/myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma: a lesion mimicking Well-Differentiated Liposarcoma
Modern pathology : an official journal of the United States and Canadian Academy of Pathology Inc, 2009Co-Authors: Munir R. Tanas, Andre M Oliveira, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan Melamed, Michele R. Erickson-johnson, Brian P RubinAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
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pseudosarcomatous fibroblastic myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma a lesion mimicking Well Differentiated Liposarcoma
Modern Pathology, 2009Co-Authors: Munir R. Tanas, Michele R Ericksonjohnson, Andre M Oliveira, Brian P Rubin, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan MelamedAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
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Detection of MDM2 gene amplification or protein expression distinguishes sclerosing mesenteritis and retroperitoneal fibrosis from inflammatory Well-Differentiated Liposarcoma.
Modern pathology : an official journal of the United States and Canadian Academy of Pathology Inc, 2008Co-Authors: Joshua Weaver, John R Goldblum, Sondra L Turner, Raymond R Tubbs, Wei Lein Wang, Alexander J. Lazar, Brian P RubinAbstract:Inflammatory Liposarcoma is a variant of Well-Differentiated Liposarcoma/atypical lipomatous tumor that consists of a mixture of lymphocytes, histiocytes, scattered atypical stromal cells, mature adipocytes, and rarely lipoblasts. When the inflammatory infiltrate predominates, the morphological features overlap with various fibroinflammatory disorders including sclerosing mesenteritis and retroperitoneal fibrosis, making the diagnosis difficult. Well-Differentiated Liposarcoma/atypical lipomatous tumor and deDifferentiated Liposarcoma have characteristic molecular markers in the form of giant marker and ring chromosomes consisting of amplicons of 12q13-15, which includes MDM2. MDM2 immunohistochemistry (IHC) (Zymed; clone IF2) and dual color fluorescence in situ hybridization utilizing MDM2 (12q15) and chromosome 12 centromeric probes were performed on formalin-fixed and paraffin-embedded specimens from inflammatory Well-Differentiated Liposarcoma (17 cases), sclerosing mesenteritis (14 cases), and idiopathic retroperitoneal fibrosis (10 cases). MDM2 expression as detected by IHC is a very sensitive tool in recognizing inflammatory Well-Differentiated Liposarcoma (17 of 17); however, 21% (3 of 14) and 10% (1 of 10) of sclerosing mesenteritis and retroperitoneal fibrosis, respectively, displayed weak MDM2 immunoexpression. The MDM2 fluorescence in situ hybridization assay was very specific for inflammatory Well-Differentiated Liposarcoma as 15 of 17 (88%) cases showed MDM2 amplification, whereas none of the cases of sclerosing mesenteritis or idiopathic retroperitoneal fibrosis showed amplification. Five cases of retroperitoneal fibrosis were noncontributory secondary to autofluorescence, potentially limiting the usefulness of the assay in certain situations such as inappropriate fixation. Increased MDM2 expression and/or MDM2 amplification can be employed to aid discrimination of inflammatory Well-Differentiated Liposarcoma from fibroinflammatory mimics. MDM2 fluorescence in situ hybridization is a very specific method (100%), but less sensitive (88%), whereas MDM2 expression by IHC is very sensitive (100%), but less specific (83%). Therefore, a positive screen of difficult cases with MDM2 IHC would require confirmation by the fluorescence in situ hybridization. However, lack of MDM2 immunoexpression would rule out the possibility of inflammatory Well-Differentiated Liposarcoma.
Andre M Oliveira - One of the best experts on this subject based on the ideXlab platform.
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carboxypeptidase m a biomarker for the discrimination of Well Differentiated Liposarcoma from lipoma
Modern Pathology, 2009Co-Authors: Michele R Ericksonjohnson, Amber R Seys, Christopher W Roth, Allison A King, Rachael L Hulshizer, Xiaoke Wang, Yan W Asmann, Ricardo V Lloyd, Eapen K Jacob, Andre M OliveiraAbstract:The discrimination between Well-Differentiated Liposarcomas/atypical lipomatous tumors and lipomas can be diagnostically challenging at the histological level. However, cytogenetic identification of ring and giant rod chromosomes supports the diagnosis of Well-Differentiated Liposarcoma/atypical lipomatous tumor. These abnormal chromosomes are mainly composed of amplified genomic sequences derived from chromosome 12q13-15, and contain several genes, including MDM2, CDK4 (SAS), TSPAN31, HMGA2, and others. MDM2 is consistently amplified in Well-Differentiated Liposarcomas/atypical lipomatous tumors, and up to 25% in other sarcomas. As part of a large genomic study of lipomatous neoplasms, we initially found CPM to be consistently amplified in Well-Differentiated Liposarcomas/atypical lipomatous tumors. To further explore this initial finding, we investigated the copy number status of MDM2 and CPM by fluorescent in situ hybridization (FISH) on a series of 138 tumors and 17 normal tissues, including 32 Well-Differentiated Liposarcoma/atypical lipomatous tumors, 63 lipomas, 11 pleomorphic lipomas, 2 lipoblastomas, 30 other tumors and 17 normal fat samples. All 32 Well-Differentiated Liposarcoma/atypical lipomatous tumors showed amplification of MDM2 and CPM, usually >20 copies per cell. The other tumors lacked MDM2 and/or CPM amplification. Chromogenic in situ hybridization confirmed the above results on a subset of these tumors (n=27). These findings suggest that identification of CPM amplification could be used as an alternative diagnostic tool for the diagnosis of Well-Differentiated Liposarcoma/atypical lipomatous tumors.
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Pseudosarcomatous fibroblastic/myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma: a lesion mimicking Well-Differentiated Liposarcoma
Modern pathology : an official journal of the United States and Canadian Academy of Pathology Inc, 2009Co-Authors: Munir R. Tanas, Andre M Oliveira, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan Melamed, Michele R. Erickson-johnson, Brian P RubinAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
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pseudosarcomatous fibroblastic myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma a lesion mimicking Well Differentiated Liposarcoma
Modern Pathology, 2009Co-Authors: Munir R. Tanas, Michele R Ericksonjohnson, Andre M Oliveira, Brian P Rubin, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan MelamedAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
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Formation of the 12q14-q15 amplicon precedes the development of a Well-Differentiated Liposarcoma arising from a nonchondroid pulmonary hamartoma.
The American journal of surgical pathology, 2006Co-Authors: Sylvain Trahan, Michele R. Erickson-johnson, Fausto J. Rodriguez, Marie Christine Aubry, John C. Cheville, Jeffrey L. Myers, Andre M OliveiraAbstract:Pulmonary hamartoma is a benign neoplasm that rarely recurs or undergoes malignant transformation. Herein, we report a 48-year-old woman with a history of an incomplete excised nonchondroid pulmonary hamartoma presenting as an indolent tumor recurrence. Excision of the tumor revealed a Well-Differentiated Liposarcoma arising from the hamartomatous component. Fluorescence in situ hybridation analysis for HMGA2 and MDM2 was performed on both hamartomatous and Liposarcomatous component. MDM2 and HMGA2 amplification were found in a subset of stromal cells in the hamartomatous component and in most cells of the Well-Differentiated Liposarcoma. No rearrangement HMGA2 was found in the pulmonary hamartoma component. These findings suggest that the formation of the 12q14-q15 chromosome amplicon, the characteristic cytogenetic finding of Well-Differentiated Liposarcomas and the structural genomic component of the supernumerary ring and giant rod chromosomes, occurred before the morphologic changes characteristic of these malignant adipose tissue tumors and likely represents a very early molecular event in their development.
Fritz C. Eilber - One of the best experts on this subject based on the ideXlab platform.
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pericytic mimicry in Well Differentiated Liposarcoma atypical lipomatous tumor
Human Pathology, 2016Co-Authors: Jia Shen, Swati Shrestha, Greg Asatrian, Michelle A. Scott, Vi Nguyen, Paulina Giacomelli, Chia Soo, Kang Ting, Nagesh P Rao, Fritz C. EilberAbstract:Pericytes are modified smooth muscle cells that closely enwrap small blood vessels, regulating and supporting the microvasculature through direct endothelial contact. Pericytes demonstrate a distinct immunohistochemical profile, including expression of smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Previously, pericyte-related antigens have been observed to be present among a group of soft tissue tumors with a perivascular growth pattern, including glomus tumor, myopericytoma, and angioleiomyoma. Similarly, malignant tumor cells have been shown to have a pericyte-like immunoprofile when present in a perivascular location, seen in malignant melanoma, glioblastoma, and adenocarcinoma. Here, we examine Well-Differentiated Liposarcoma specimens, which showed some element of perivascular areas with the appearance of smooth muscle (n = 7 tumors). Immunohistochemical staining was performed for pericyte antigens, including smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Results showed consistent pericytic marker expression among Liposarcoma tumor cells within a perivascular distribution. MDM2 immunohistochemistry and fluorescence in situ hybridization for MDM2 revealed that these perivascular cells were of tumor origin (7/7 tumors), whereas double immunohistochemical detection for CD31/CD146 ruled out an endothelial cell contribution. These findings further support the concept of pericytic mimicry, already established in diverse malignancies, and its presence in Well-Differentiated Liposarcoma. The extent to which pericytic mimicry has prognostic significance in Liposarcoma is as yet unknown.
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Pericytic mimicry in Well-Differentiated Liposarcoma/atypical lipomatous tumor
Human pathology, 2016Co-Authors: Jia Shen, Swati Shrestha, P. Nagesh Rao, Greg Asatrian, Michelle A. Scott, Vi Nguyen, Paulina Giacomelli, Chia Soo, Kang Ting, Fritz C. EilberAbstract:Pericytes are modified smooth muscle cells that closely enwrap small blood vessels, regulating and supporting the microvasculature through direct endothelial contact. Pericytes demonstrate a distinct immunohistochemical profile, including expression of smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Previously, pericyte-related antigens have been observed to be present among a group of soft tissue tumors with a perivascular growth pattern, including glomus tumor, myopericytoma, and angioleiomyoma. Similarly, malignant tumor cells have been shown to have a pericyte-like immunoprofile when present in a perivascular location, seen in malignant melanoma, glioblastoma, and adenocarcinoma. Here, we examine Well-Differentiated Liposarcoma specimens, which showed some element of perivascular areas with the appearance of smooth muscle (n = 7 tumors). Immunohistochemical staining was performed for pericyte antigens, including smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Results showed consistent pericytic marker expression among Liposarcoma tumor cells within a perivascular distribution. MDM2 immunohistochemistry and fluorescence in situ hybridization for MDM2 revealed that these perivascular cells were of tumor origin (7/7 tumors), whereas double immunohistochemical detection for CD31/CD146 ruled out an endothelial cell contribution. These findings further support the concept of pericytic mimicry, already established in diverse malignancies, and its presence in Well-Differentiated Liposarcoma. The extent to which pericytic mimicry has prognostic significance in Liposarcoma is as yet unknown.
Michele R Ericksonjohnson - One of the best experts on this subject based on the ideXlab platform.
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carboxypeptidase m a biomarker for the discrimination of Well Differentiated Liposarcoma from lipoma
Modern Pathology, 2009Co-Authors: Michele R Ericksonjohnson, Amber R Seys, Christopher W Roth, Allison A King, Rachael L Hulshizer, Xiaoke Wang, Yan W Asmann, Ricardo V Lloyd, Eapen K Jacob, Andre M OliveiraAbstract:The discrimination between Well-Differentiated Liposarcomas/atypical lipomatous tumors and lipomas can be diagnostically challenging at the histological level. However, cytogenetic identification of ring and giant rod chromosomes supports the diagnosis of Well-Differentiated Liposarcoma/atypical lipomatous tumor. These abnormal chromosomes are mainly composed of amplified genomic sequences derived from chromosome 12q13-15, and contain several genes, including MDM2, CDK4 (SAS), TSPAN31, HMGA2, and others. MDM2 is consistently amplified in Well-Differentiated Liposarcomas/atypical lipomatous tumors, and up to 25% in other sarcomas. As part of a large genomic study of lipomatous neoplasms, we initially found CPM to be consistently amplified in Well-Differentiated Liposarcomas/atypical lipomatous tumors. To further explore this initial finding, we investigated the copy number status of MDM2 and CPM by fluorescent in situ hybridization (FISH) on a series of 138 tumors and 17 normal tissues, including 32 Well-Differentiated Liposarcoma/atypical lipomatous tumors, 63 lipomas, 11 pleomorphic lipomas, 2 lipoblastomas, 30 other tumors and 17 normal fat samples. All 32 Well-Differentiated Liposarcoma/atypical lipomatous tumors showed amplification of MDM2 and CPM, usually >20 copies per cell. The other tumors lacked MDM2 and/or CPM amplification. Chromogenic in situ hybridization confirmed the above results on a subset of these tumors (n=27). These findings suggest that identification of CPM amplification could be used as an alternative diagnostic tool for the diagnosis of Well-Differentiated Liposarcoma/atypical lipomatous tumors.
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pseudosarcomatous fibroblastic myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma a lesion mimicking Well Differentiated Liposarcoma
Modern Pathology, 2009Co-Authors: Munir R. Tanas, Michele R Ericksonjohnson, Andre M Oliveira, Brian P Rubin, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan MelamedAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
Munir R. Tanas - One of the best experts on this subject based on the ideXlab platform.
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Pseudosarcomatous fibroblastic/myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma: a lesion mimicking Well-Differentiated Liposarcoma
Modern pathology : an official journal of the United States and Canadian Academy of Pathology Inc, 2009Co-Authors: Munir R. Tanas, Andre M Oliveira, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan Melamed, Michele R. Erickson-johnson, Brian P RubinAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.
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pseudosarcomatous fibroblastic myofibroblastic proliferation in perinephric adipose tissue adjacent to renal cell carcinoma a lesion mimicking Well Differentiated Liposarcoma
Modern Pathology, 2009Co-Authors: Munir R. Tanas, Michele R Ericksonjohnson, Andre M Oliveira, Brian P Rubin, Chalenpoj Sthapanachai, Daisuke Nonaka, Jonathan MelamedAbstract:Cytologically atypical stromal cells were found in the perinephric adipose tissue, mimicking Well-Differentiated Liposarcoma in 12 of 59 (20%) consecutive nephrectomy specimens that were resected for renal cell carcinoma. Morphologically, the atypical cells included enlarged, hyperchromatic spindle cells and floret-type multinucleate cells. Of 59, 10 (17%) renal cell carcinomas invaded through the renal capsule into the perinephric adipose tissue. Of these cases, three (30%) contained the aforementioned atypical cells. In contrast, 9 of 49 cases without extrarenal invasion (18%) contained the atypical stromal cells. Of the 12 cases with atypical stromal cells, 3 (25%) were associated with extrarenal involvement. The atypical spindle cells exhibited focal to variable positivity for smooth muscle actin and desmin in 3 of the 14 cases (including two cases from our consultation files) each. Cytokeratin AE1/AE3, cytokeratin Cam 5.2, cytokeratin 7, epithelial membrane antigen, and S-100 were negative in all cases. Amplification of MDM2 gene region, which is commonly observed in Well-Differentiated Liposarcoma, was absent by fluorescence in situ hybridization (FISH) in the atypical stromal cells. Immunohistochemistry and FISH suggest that the atypical cells are most consistent with reactive fibroblasts/myofibroblasts. Recognition of these atypical fibroblasts/myofibroblasts may help in avoiding the potential pitfall of misdiagnosing them as Well-Differentiated Liposarcoma.