Biomedical subjects
Jean-Paul Saint-André
Publications and source records attributed to Jean-Paul Saint-André.
Sources of variability in histological scoring of chronic viral hepatitis.
Inter-observer agreement on activity and fibrosis scores used in chronic viral hepatitis has only been studied under selected conditions. The aim of this study was to identify the sources of variability due to specimen characteristics and observers. This study included 254 liver specimens and 15 pathologists and used the Metavir score. In 44 specimens scored by 4 academic pathologists, agreement of Metavir score was good overall, but better for fibrosis (kappa = 0.59) than for activity (kappa = 0.43) and poor for lobular necrosis (kappa = 0.15). The mean agreement was better for senior (0.60 +/- 0.24) than junior pathologists (0.52 +/- 0.30, P < .05). Mean intrabserver agreement was better than inter-observer agreement (0.77 +/- 0.18 vs. 0.58 +/- 0.26, P < .01). In 157 specimens scored by 2 expert pathologists (one senior, one junior), agreement of Metavir score was only good but greatly improved after consensus reading (fibrosis: kappa = 0.48 and 0.77, activity: kappa = 0.44 and 0.70, respectively, before and after consensus). Several causes of disagreement were identified: specimen length, fibrosis class number, observer bias, and putative causes related to Metavir score or specimen. In an intercenter evaluation involving 59 specimens, 1 expert and 10 nonacademic pathologists, agreement was very poor and did not improve over 5 years for activity (kappa = 0.22-0.25) or fibrosis (kappa = 0.13-0.18). In conclusion, the level of experience (specialization, duration, and location of practice) has more influence on agreement than the characteristics of the specimen (length, fibrosis class number, miscellaneous factors). Agreement can be improved by experienced pathologist or consensus reading.
C-cell hyperplasia and medullary thyroid carcinoma: clinicopathological and genetic correlations in 66 consecutive patients.
Routine calcitonin (CT) assay programs and genetic testing for RET proto-oncogene mutations have consistently modified the management and understanding of C-cell proliferative disorders. We report a series of 66 consecutive patients with C-cell hyperplasia (CCH) or medullary thyroid carcinoma (MTC) observed in our institution within an 8-year time period. All the patients had a preoperative basal CT assay and an RET proto-oncogene sequencing. Seventeen patients (F-M ratio: 8:9, mean age: 29.7 y) had a multiple endocrine neoplasia Type 2: 3 children <10 years of age had CCH only, and 14 patients had an MTC, with neoplastic CCH in 10/14 cases. Twenty-seven patients (F-M ratio: 18:9, mean age: 56.6 y) had a sporadic MTC, with physiological CCH in 8 and neoplastic CCH in 3 cases. Twenty-two men (mean age: 46.2 y) had CCH only (physiological CCH in 17 men and neoplastic CCH in 5). We conclude that (1) clinical and pathological characteristics (familial MTC, tumor multifocality, neoplastic CCH) usually associated with hereditary MTC may be misleading and that on the contrary, RET sequencing gives no false positive result; (2) sporadic neoplastic CCH accompanies (and probably precedes) a number of sporadic MTC; and (3) women presenting with a sporadic elevated basal CT have a 100% risk of having an MTC (15/15), but this risk is 3-fold less in men (31%), who will most often have CCH only (69%).
[Diagnosis of the follicular variant of papillary thyroid carcinoma. Significance of immunohistochemistry].
AIMS: To study the expression of cytokeratin 19 (CK-19), HBME-1 and Ret in follicular-patterned thyroid tumors, and their significance for the diagnosis of the follicular variant of papillary thyroid carcinoma. MATERIALS AND METHODS: 111 well-differentiated follicular tumors were examined by immunohistochemistry: 59 papillary carcinomas (43 of the follicular variant), 40 follicular adenomas (among which 11 atypical adenomas), 10 oxyphil cell tumors and 2 follicular carcinomas. RESULTS: CK-19 was diffusely expressed in all the papillary carcinomas, and was also expressed in 2/4 oxyphil cell carcinomas and 4/11 atypical adenomas. 90% of the follicular adenomas (26/29), the six oxyphil cell adenomas and the two follicular carcinomas showed at best a focal staining of dystrophic areas. 78% of the papillary carcinomas and 3/11 atypical adenomas were stained with HBME-1, whereas 26/29 adenomas (90%) and the 10 oxyphil cell tumors were negative. 34% of the papillary carcinomas expressed Ret (most of them were of the usual type (14/20)). The staining was often weak and focal (13/20). The other tumors were all negative for Ret. CONCLUSIONS: CK-19 is a sensitive (100%) and specific (82.5%) marker of papillary carcinomas, which can be helpful in the diagnosis of its follicular variant. HBME-1 can improve this specificity when associated with CK-19. The Ret protein expression is of limited practical interest.
[Definition and histologic characterization of neuroendocrine tumors].
Neuroendocrine tumours are defined by a common phenotype, which is not supported by a common embryologic origin. This common phenotype is characterized by the expression of general neuroendocrine markers, and sometimes by cell specific hormonal products. Neuroendocrine tumours are ubiquitous, but the major localizations are the digestive tract. According to the classification of lung tumours, they are divided in low grade and high grade tumours. Since most digestive and pancreatic tumours are low grade tumours, a specific classification of neuroendocrine tumours was recently proposed. Size, degree of invasion, major secretion, and proliferation rate are the main criteria of this classification. Most neuroendocrine tumours are sporadic. A few cases occur in the context of a multiple endocrine neoplasia type 1.
Renal involvement in monoclonal (type I) cryoglobulinemia: two cases associated with IgG3 kappa cryoglobulin.
Renal involvement has been described rarely in monoclonal (type I) cryoglobulinemia, although this complication is frequent among patients with mixed (type II or III) cryoglobulin. We report two patients with glomerulonephritis and monoclonal IgGkappa cryoglobulin. Both patients presented with nephrotic syndrome, microscopic hematuria, and impaired renal function. Hepatitis C serology was negative, bone marrow aspiration was normal, and the renal biopsy specimen showed membranoproliferative glomerulonephritis with glomerular subendothelial deposits of monoclonal IgGkappa. In both cases, circulating cryoglobulin and monotypic tissue deposits were found to be IgG3kappa, suggesting that this isotype may have a particular propensity to cause this type of membranoproliferative glomerulonephritis. Although 18 cases of type I cryoglobulinemia with biopsy-proven glomerulonephritis have been reported to date, this is the first characterization of immunoglobulin heavy-chain isotype in this disease.
Incidental langerhans cell histiocytosis of thyroid: case report and review of the literature.
We report a case of a 42-yr-old woman with Langerhans cell histiocytosis (LCH) confined to the thyroid and associated with lymphocytic thyroiditis and a papillary microcarcinoma. This patient remains free of symptoms 14 mo after surgery. Thyroid LCH is rare. In children, it usually occurs as part of a multisystemic disease, whereas it is usually exclusive in adults. Isolated thyroid LCH is frequently associated with another thyroid disease, especially lymphocytic thyroiditis, suggesting that it is a reactive process rather than a neoplastic proliferation. The prognosis of isolated thyroid LCH is good. However, because it can rarely precede or reveal a multisystemic disease, additional investigations as well as a prolonged follow-up are justified.