Germline mosaicism in Rett syndrome identified by prenatal diagnosis.

Rett syndrome is an X-linked neurodevelopmental dominant disorder that affects almost exclusively girls. The vast majority of cases are sporadic and are caused by de novo mutations in the MECP2 gene, located in Xq28. Only few familial cases have been reported: in four cases, the mother was an asymptomatic carrier and in other four cases, the germline mosaicism in the mother was postulated. Owing to the above reported cases of germline mosaicism, we decided to offer prenatal diagnosis to all expectant mothers with a Rett daughter despite the absence of the causative mutation in parents' blood. We describe here the outcome of the first nine cases of prenatal diagnosis followed by our center. In eight cases, the fetus did not carry the mutation. In one case, the female fetus did carry the same mutation of the affected sister. The couple decided to interrupt the pregnancy and to devolve fetal tissues for research purposes. Our results indicate that prenatal diagnosis should be proposed to all couples with a Rett daughter, even when the mutation is apparently de novo. Moreover, one positive prenatal test among the first nine cases indicates that germline mosaicism may be seriously considered for the assessment of recurrence risk during genetic counseling.

Lipomatous mixed tumour of the skin: a histological, immunohistochemical and ultrastructural study.

BACKGROUND: Mixed tumours are composed of an admixture of an epithelial/myoepithelial and usually a myxochondroid stromal component. Adipocytes are found more rarely, and account for a minor part of the tumour. To date, only three cases of mixed tumour/pleomorphic adenoma of the salivary gland have been described, showing an extensive adipocyte content of more than 90% of the tumour tissue. Owing to this peculiarity, some authors have defined it as 'lipomatous pleomorphic adenoma'. We are not aware of previously reported similar lesions in the skin. OBJECTIVES: We report a case of a tumour that occurred as a 2 x 2 x 1.5 cm nodule in the scalp of a 65-year-old man. Analogies with salivary lipomatous pleomorphic adenoma, as well as histogenesis and differential diagnoses are discussed here. METHODS: A histological, immunohistochemical and ultrastructural study was performed. RESULTS: The tumour was well-circumscribed and showed a substantial mature adipose tissue component intermingled with epithelial cells arranged in ducts and branching tubules, embedded in a fibromyxoid stroma, which was diagnostic of a chondroid syringoma/mixed tumour. Adipocytes strongly expressed S-100 protein and cytokeratin 14. Transitional elements from epithelial/myoepithelial cells into adipocytes were observed. They coexpressed cytokeratin 14, S-100 protein and vimentin, and showed lipid droplets, desmosome-type junctions, cytoplasmic tonofilaments and basal lamina. CONCLUSIONS: The tumour differed from lipomas with myxoid stroma and from lipoadenomas, which show non-proliferating normal sweat glands admixed with adipose tissue. Because of the similarity to lipomatous pleomorphic adenoma/mixed tumour of salivary glands, we suggest that it should be called 'lipomatous mixed tumour of the skin'.

Quantitative in situ evaluation of telomeres in fluorescence in situ hybridization-processed sections of cutaneous melanocytic lesions and correlation with telomerase activity.

BACKGROUND: Telomere length is correlated with cellular ageing and immortalization processes. In some human cancers telomere length measurement has proved to be of diagnostic and prognostic value. Results comparable with the traditional terminal restriction fragment length determination by Southern blotting have been obtained in metaphase and interphase cells in some studies by fluorescence in situ hybridization (FISH) analysis; FISH additionally allows for the quantification of telomeres at the cellular level. OBJECTIVES: In this study, 32 melanocytic lesions were analysed by FISH, aiming at investigating possible telomere differences among various benign and malignant lesions and correlation with telomerase activity (TA) level. METHODS: FISH was performed on paraffin sections from six common naevi, eight Spitz naevi, 12 melanomas, six melanoma metastases and nine control samples of normal skin. Telomere mean maximum diameter (Feret max), area and number per nuclear area were calculated by image analysis on fluorescent images elaborated through KS400 and in situ imaging system (ISIS) for FISH analysis programs. Mean TA level was also calculated in all lesions and correlated with telomere parameters. RESULTS: Telomere number per nuclear area was significantly lower in melanomas and metastases than in benign common and Spitz naevi and in control skin (7 small middle dot24 +/- 3.3; 6.11 +/- 3 vs. 14.46 +/- 5.6; 16.92 +/- 7.8; and 12.59 +/- 3.4, respectively; P < 0 .001). No significant differences were found for the other telomere parameters. In common and Spitz naevi, telomere number was positively correlated with Feret max (P = 0.046 and P < 0.0001, respectively). TA was significantly higher in melanomas and metastases than in the other groups (70.18 +/- 25.2; 105.07 +/- 30 vs. 2.16 +/- 2.4; 2 .99 +/- 2.1; 2 +/- 1.2, respectively; P< or = 0. 001) and it was inversely correlated with telomere number per nuclear area in melanomas (P = 0.0041). No other significant correlations were found. CONCLUSIONS: Encouraging results have been obtained from quantitative telomere evaluation in the diagnosis of melanocytic lesions, although an analysis of a larger number of cases would be necessary to provide more reliable data. An extreme shortening of some telomeres probably results in the decrease of telomeric signals and the lower mean number of detectable telomeres in melanomas and metastases. In melanomas, telomere number per nuclear area is also inversely correlated with TA levels. Quantitative FISH of melanocytic lesions could give more specific information at the cellular level in telomere and telomerase fields of investigation.

Telomerase activity, Ki-67, cyclin D1 and A expression, and apoptosis in solitary fibrous tumors: additional features of a predictable course?

Solitary fibrous tumors (SFTs) are infrequent soft tissue neoplasms which are usually benign and surgically curable. However, their behavior is not always predictable, although several clinical and pathological criteria of malignancy have been established. In many cancers, including some soft tissue tumors, telomerase activity (TA) has been shown to be a new reliable pathological marker of malignancy. Overexpression of some cyclins is associated with higher degrees of malignancy and predictive of the clinical course. In this study, we evaluated TA, mitotic and apoptotic indices (MI, AI), and the expression of Ki-67, cyclins D1 and A in five typical and two clinicopathologically atypical SFTs, the latter two of which had also recurred. High TA was demonstrated in the two atypical cases, which also showed a higher labeling index to Ki-67, as well as higher cyclin D1 and A expression, and either none or very few apoptoses. We suggest that TA, Ki-67, cyclin expression, and AI be evaluated in SFTs as possible adjunctive pathological criteria of behavior.

Cell proliferation, cell death, E-cadherin, metalloproteinase expression and angiogenesis in gastric cancer precursors and early cancer of the intestinal type.

The aim of this study was to analyse the morphological, kinetic and molecular characteristics of low-grade (LGD) and high-grade dysplasias (HDG) in comparison with intestinal metaplasia type III (IM III) and normal mucosa (NM) as well as with early gastric cancer of the intestinal type (EGC). Based on this it was verified whether these categories are distinct, progressive proliferative steps from IM III to LGD, HGD and EGC, according to Correa's sequence of events. The morphology, mitotic index (MI), and the apoptotic index (AI) were assessed. The E-cadherin expression (E-Cad), matrix-metalloproteinase activity (MMP2), and the number of microvessels (NV) were also evaluated. Among the categories, MI increases from NM to IM III and LGD, and from LGD to HGD and EGC, while AI continues to increase also from HGD to EGC. E-cad decreases from NM to EGC, although not significantly from LGD to HGD; MMP2 is significantly more expressed only in EGC. Three groups are obtained by means of cluster analysis. The first group includes all the NMs and IM IIIs, all except 1 LGD, about half of HGDs, and 1 EGC. E-Cad is highly expressed, MMP2 and angiogenesis are low, the proliferative activity is low and mitoses are partly balanced by apoptoses. The second group includes some EGCs and HGDs and is characterised by a very high proliferative activity and cell death; there is an initial loss of cell adhesion, an increase of MMP2 and NV. The third group includes the majority of EGCs, but also 1 HGD: it has intermediate MI and AI, the lowest expression of E-Cad, the highest expression of MMP2 and the most numerous microvessels. These results underscore the necessity of evaluating each case individually within the same singular category of Correa's sequence. The use of kinetic and molecular parameters in addition to the morphological analysis may give important information on the behaviour of the various lesions.

Cyclooxygenase-2 immunoreactivity in the ischemic neonatal human brain. An autopsy study.

Cyclooxygenase-2 (COX-2) is known to be expressed in rat brain and up-regulated by ischemia. The administration of COX inhibitors before as well as soon after the ischemic insult reduces the extension of cerebral damage in rats. Overexpression of COX-2 has also been shown in the ischemic brain of adult human patients, while no information concerning COX-2 expression in neonatal ischemia is available. Intrapartum asphyxia and perinatal brain injury may result in cerebral palsy, mental retardation or epilepsy. COX-2 expression in the brain of neonates delivered after severe birth asphyxia was investigated using immunohistochemistry. Meningeal vessel walls of term and preterm babies widely expressed COX-2 immunoreactivity, as did periventricular large vessels in preterms. A number of brain cells (mature and immature cortical, periventricular and basal ganglia neurons, and oligodendrocytes of the cerebral white matter in brains from term neonates) also expressed COX-2. The present findings suggest that COX-2 may take part in enhancing neonatal brain damage via different mechanisms, such as those involving excitotoxicity and production of reactive oxygen species.

Acute thymic involution in fetuses and neonates with chorioamnionitis.

Chorioamnionitis represents the leading cause of preterm birth and related pathologic conditions as well as of fetal death and frequently occurs in symptom-free mothers. Recent radiologic findings have indicated that thymus size is significantly reduced in preterm infants born to mothers with subclinical, histologically proven chorioamnionitis. However, an accurate morphologic description of the thymus gland in fetuses and neonates with chorioamnionitis is lacking, although it is known that infection and other stress processes may cause lymphocyte depletion in the thymuses of infants and older babies (acute stress involution). We describe morphologic modifications in the thymus of fetuses with histologically proven chorioamnionitis and newborn infants with chorioamnionitis and proven sepsis. The main findings included (1) decreased organ volume (ANOVA, P < .0024); (2) reduced corticomedullary ratio (P < 10(-6)); (3) significant changes in the relationship between thymic parenchyma and thymic interstitial tissue with resulting increased organ complexity (P = .03); (4) severe reduction of thymocytes; and (5) other degenerative processes such as monocyte/macrophage infiltration of Hassall's bodies. These results indicate that chorioamnionitis, with or without sepsis, is associated with significant morphologic modifications in the thymus. We wish to note that the described thymic pathology is only one aspect of the fetal systemic inflammatory response syndrome with which chorioamnionitis is associated.

Microcystic adenoma of the pancreas (glycogen-rich cystadenoma) with stromal amyloid deposits.

AIMS: We report a case of a pancreatic glycogen-rich microcystic serous adenoma with stromal amyloid deposits, focusing on the significance of isolated amyloid deposits in tumours. METHODS AND RESULTS: The architectural pattern was characterized by thin-walled cysts lined by a single layer of flat or cuboidal epithelial cells intensely stained by the PAS-reaction only before diastase digestion, suggesting the presence of glycogen. Tumour stroma was composed of broad fibrocollagenous tissue with lamellar hyalinized areas which were positively stained by Congo red and showed green birefringence and dichroism with polarized light. For amyloid protein characterization, immunohistochemical studies were performed with anti-beta amyloid protein and anti-amyloid precursor pre-A4695. The former antibody diffusely stained tumour stroma, while the latter stained only scattered stroma cells. CONCLUSIONS: This is the first documented case of amyloid deposition in pancreatic serous adenoma. We indicate that the source of amyloid is an APP-like precursor secreted by stromal myofibroblasts.

Scarring in papillary carcinoma of the thyroid: report of two new cases with exuberant nodular fasciitis-like stroma.

AIMS: To describe two new cases of papillary carcinoma of the thyroid with exuberant nodular fasciitis-like stroma, one of which was characterized by previously unreported transformation into a poorly differentiated lesion. Moreover, we explore the presence of TGF-beta to help to clarify the pathogenesis of the collagen formation. METHODS AND RESULTS: The case characterized by an aggressive behaviour exhibited areas of transformation into a poorly differentiated (insular) carcinoma of the thyroid. In both cases, as revealed by immunohistochemistry, neoplastic cells produced and secreted high amounts of TGF-beta. On the contrary, TGF-beta immunoreaction was never present in the normal thyroid or in papillary carcinomas without collagen bundles, while a weak, exclusively intracellular reaction was present in a patchy manner in cases showing intratumoral fibrous bundles. CONCLUSIONS: The rare variant of papillary thyroid carcinoma characterized by exuberant stroma may give rise to more aggressive lesions, as do other histotypes of differentiated thyroid carcinomas. TGF-beta, the fundamental cytokine which mediates scarring and activation of myofibroblasts, most probably induces the exuberant stroma.