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Biomedical subjects

M Le Charpentier

Publications and source records attributed to M Le Charpentier.

At least 19 recordsLinked to original sources
PubMed2004

Severe hepatic sinusoidal obstruction associated with oxaliplatin-based chemotherapy in patients with metastatic colorectal cancer.

BACKGROUND: In advanced metastatic colorectal adenocarcinoma, the addition of a neo-adjuvant systemic treatment to surgery might translate into a survival advantage, although this is yet to be confirmed by ongoing randomized trials. The objective of this study was to assess the effects of preoperative systemic chemotherapy on the morphology of non-tumoral liver. PATIENTS AND METHODS: A large series of surgically resected liver metastases (n=153) was selected. Light microscopy, electron microscopy, and immunohistochemistry using antibodies against endothelial cells (CD31) and hepatic stellate cells (alpha-SM actin, CRBP-1) were performed to identify sinusoidal wall integrity. RESULTS: We found that 44 (51%) of the 87 post-chemotherapic liver resection specimens had sinusoidal dilatation and hemorrhage, related to rupture of the sinusoidal barrier. In contrast, the 66 livers treated by surgery alone remained normal. In 21 out of the 44 post-chemotherapy patients (48%), perisinusoidal and veno-occlusive fibrosis also developed. Sinusoidal injury persisted several months after end of chemotherapy, and fibrosis may progress. Development of lesions was strongly correlated to the use of oxaliplatin; 34 out of 43 patients (78%) treated with this drug showed striking sinusoidal alterations. CONCLUSIONS: Systemic neo-adjuvant chemotherapy in metastatic colorectal cancer frequently causes morphological lesions involving hepatic microvasculature. Sinusoidal obstruction, complicated by perisinusoidal fibrosis and veno-occlusive lesion of the non-tumoral liver revealed by this study, should be included in the list of the adverse side-effects of colorectal systemic chemotherapy, in particular related to the use of oxaliplatin.

Adenocarcinoma↗
PubMed2003

[Melanotic schwannoma, a tumor with a unpredictable prognosis: case report and review of the literature].

A large sporadic melanotic schwannoma was found at the C2-C3 level in a 66-year-old woman who presented a pyramidal syndrome of all four limbs. The diagnosis was established by histology and immunohistochemical studies and confirmed by ultrastructural examination. Thirty-six cases of melanotic schwannoma located in the spinal cord have been reported in the literature, allowing an analysis of the different histological, clinical, and therapeutic aspects. Usually considered as benign tumor, melanotic schwannoma can recur and progress to malignancy, requiring long-term follow-up, specially in patients with multiple tumors and/or Carney's syndrome.

Aged↗
PubMed2001

[Adrenocortical tumors with oncocytic cells: benign or malignant?].

Adrenocortical tumor with oncocytic cells are exceptional. They are composed exclusively or almost exclusively of oncocytic cells, which are large cells with eosinophilic granulations, corresponding to numerous mitochondria in electronic microscopic examination. This tumor is usually non-functional and benign, and has to be differentiated from the adrenocortical carcinoma.

Adenoma, Oxyphilic↗
PubMed2000

[Renal angiomyolipoma with predominant muscular epithelioid components. 2 cases].

We report two cases of pararenal angiomyolipomas, in two middle-aged women without tuberous sclerosis. Both tumors were made of muscular epithelioid cells without atypia, some of which were stained by HMB-45 antibody. The fibrous stroma contained numerous thick-walled blood vessels but no adipose component. The ultrastructural examination revealed that muscular epithelioid cells contained myofilaments and melanosomas. Because of their immunohistochemical and ultrastructural profiles, both tumors may be included in the family of lesions composed of perivascular epithelioid cells (PEC). This tumor type is considered as a particular variant of angiomyolipoma with predominant muscular epithelioid component. The immunohistochemical expression of progesterone and estrogen receptors by both tumors may suggest their hormonodependent character.

Adult↗
PubMed1999

[Renal medullary carcinoma, a new clinico-pathological entity. Immunohistochemical, ultrastructural, flow cytometric and cytogenetic study of a case].

The renal medullary carcinoma is a rare tumor. We report a case in a black patient with sickle cell trait. The tumor was located in the lower pole of the left kidney. It had a tubular and microcystic architecture. It was composed of large eosinophilic cells with vesicular nuclei containing prominent nucleoli, in a desmoplastic and inflammatory stroma. By immunohistochemistry, the tumoral cells were positive for cytokeratin and Ulex europaeus lectin. Electron microscopy revealed small intracytoplasmic lumina with microvilli. The flow cytometric study showed DNA-multiploidy. The cytogenetic study revealed tetraploidy without structural abnormality. The renal medullary carcinoma is often reported in young black patients with sickle cell trait. Its microscopic, immunohistochemical and ultrastructural features favor its identification as a particular variety of Bellini duct carcinoma. Its link with sickle cell trait has to be defined.

Adult↗
PubMed1998

Ultrastructural and immunohistochemical observations concerning laminin in B16 melanoma. Is an amorphous form of laminin promoting a non hematogenous migration of tumor cells?

The gravity of cancer is related to the propensity of tumor cells to migrate from a primary site to distant organs. It is generally accepted that tumor migration occurs in the vascular stream, via the endothelial basement membrane or lamina. A recent study identified in human malignant melanomas an angio-tumoral association (termed the angio-tumoral complex) characterized by an amorphous material juxtaposed between endothelial cells and tumor cells that contained laminin. The absence of any sign of intravasation and the pericytic location of tumor cells in this typical image raised the question of the role of these complexes in promoting tumorigenesis. Using the mouse B16 melanoma model, we observed an increase of angio-tumoral complexes with tumor progression, again without any evidence of intravasation. Given the role of laminin in migration and metastasis, we discuss a non hematogenous mechanism of tumor migration along the abluminal surface of endothelium.

Animals↗
PubMed1998

Angio-tumoral laminin in murine tumors derived from human melanoma cell lines. Immunohistochemical and ultrastructural observations.

Cells in tissues interact with each other and with the extracellular matrix as part of a structural and informational unit. During cancer progression, tumor cells participate in the formation of a neotissue involving other cells and matrix. We recently observed in melanoma an association between tumor and endothelial cells via an amorphous matrix containing free laminin. The pericytic location of melanoma cells in this angio-tumoral complex raised the question of an intramesenchymal migration of metastatic melanoma cells promoted by free laminin along the endothelium. However the respective roles of melanoma cells and endothelial cells in laminin secretion were not clear. In an attempt to clarify the latter issue, we injected into mice three human melanoma cells lines, one secreting laminin and two that did not, in order to identify the source of laminin secretion in the subsequent interactions between tumor cells and vascular endothelium. Using immunohistochemistry and electron microscopy we observed in all three cases an amorphous matrix containing laminin between tumor and endothelial cells. The fact that two cell lines did not secrete laminin suggests that the periendothelial/peritumoral laminin could be of endothelial origin. Given the presence of laminin alone during intramesenchymal angiogenesis and embryogenesis, we propose an analogous role for endothelial laminin in facilitating the migration of melanoma cells along the abluminal surface of the endothelium.

Animals↗
PubMed1996

Fine-needle sampling of a case of carcinoma of the breast with neuroendocrine differentiation.

Fine-needle sampling was performed in a woman with a left breast lump. The cytologic diagnosis was consistent with a poorly-differentiated carcinoma. Cytologic features included medium-to-large, round, and spindle-shaped cells with scanty cytoplasm, nuclear molding, and rosette-like structures. Histology revealed an endocrine pattern. Immunohistochemical staining was positive for epithelial and neuroendocrine markers, and electron microscopy showed many small membrane-bound electron-dense granules, confirming the diagnosis of breast carcinoma with neuroendocrine differentiation. DNA flow cytometry and cytogenetic analyses revealed a near-tetraploid tumor.

Biopsy, Needle↗
PubMed1995

[Alveolar sarcomas of soft tissues. Immunohistochemical, ultrastructural study and flow cytometry].

Alveolar soft tissue sarcoma is an unusual tumor, known to have a poor prognosis. Although a muscular origin has been supported by most authors, the histogenesis of such tumors remains unclear. We report a case of alveolar soft tissue sarcoma with histological, ultrastructural, immunohistochemical and flow cytometry study. Pour results support a myogenic origin of these tumors and demonstrate its aneuploid nature. Pulmonary metastasis occurred early in spite of intensive chemotherapy and surgical removal of the tumor.

Adult↗
PubMed1977

[Intranuclear inclusions in giant cell bone tumor. Demonstration by electron microscopy].

In a case of giant cell tumour of bone, electron microscopy revealed filamentous inclusions within the nuclei of all the giant cells. Although not invariably present in such tumours, their similarity with the nucleocytoplasmic inclusions seen in osteoclasts in Paget's disease is underlined. This raises interesting questions as to their nature and the histogenesis of these disorders.

Adult↗