Neuroendocrine, immunohistochemical, and ultrastructural study of pineal region tumors.

Thirteen patients with tumors in the pineal region were submitted to pre- and post-operative blood sampling (08:00, 14:00, 20:00, and 02:00 hr) for three or four consecutive days. A single cerebrospinal fluid (CSF) sample was collected at surgery, and melatonin levels determined. In all patients, serum and CSF beta subunit of human chorionic gonadotrophin (betaHCG), carcino embryonic antigen (CEA), and alpha-fetoprotein (AFP) levels were measured. Histology revealed four pineocytomas, one pineoblastoma, four germinomas, one immature teratoma, one pilocytic astrocytoma, one lymphoma, and one meningioma. Serum and CSF levels of serological biomarkers were normal, except for one of the germinoma cases. In most patients, alteration either in the circadian rhythm or in the melatonin concentration was observed before surgery. In benign neoplasms the circadian rhythm was conserved. In pineoblastoma, lymphoma, and three out of four germinomas, melatonin concentrations were undetectable. In one case of germinoma, melatonin levels were high, with the circadian rhythm being abolished. According to conventional histology, all germinomas were similar. Therefore, in a rare case of pineal germinoma with high melatonin levels, the tissue was subjected to an in depth investigation (immunohistochemical and ultrastructural) in order to determine the pathology and the possible differences from the other typical germinomas. Results were compared to those provided from other pineal neoplasms. Electron microscopy examination detected the presence of clusters of intermediate filaments and numerous electrondense granules only in the case of a germinoma producing melatonin.

Cerebral rhabdomyosarcoma with rhabdoid tumor-like features.

The present paper describes a case of cerebral neoplasm presenting histological-immunohistochemical characteristics of malignant rhabdoid tumor (MRT) and ultrastructural features of both MRT and rhabdomyosarcoma (R). MRT was first described as an aggressive neoplasm of unknown histogenesis of the kidney, then many other sites of onset were reported, including the central nervous system. However, it has been shown that other tumors of known histogenesis can mimic histologic and ultrastructural features of MRT. On the basis of our findings we agree with authors who support the notion that extrarenal MRT has often a different histogenesis from MRT of kidney, and it probably is a 'phenotypic' entity rather than a distinct pathologic entity.

Singular case of tardive anastomotic disjunction in a Dacron R vascular graft.

We investigated a case of anastomotic disjunction of the termino-lateral insertion of a bifurcate aortic graft in the right external iliac artery. The graft in woven Dacron R n. 19, was implanted in 1977 and the left femoral insertion became infected shortly after surgery. The infection was treated according to standard procedures with removal of the infected branch, reconstruction with the transobturatory by-pass and antibiotics. For antibiotic treatment of local and general sepsis the approach was completely new as regards dose regimen and duration. In 1993 a pseudoaneurysm developed through weakening of the right iliac anastomosis. In view of the anamnesis we were surprised to find that the origin was of a mechanical nature.

Anastomotic disjunction in long-term patent vascular synthetic grafts in Dacron.

This study follows the recently published paper on the in vivo behaviour of patent Dacron vascular prostheses and focuses in particular on anastomotic disjunction. The question of the evolution of anastomoses was tackled by examining its three basic components: prosthetic tissue, suture thread and arterial wall. The authors' observations were based on material taken from reoperations performed between 7 and 18 years after the first graft. These data enable the authors to affirm that the prosthesis undergoes a general physical and chemical deterioration which varies in intensity according to the type of weaving. On the contrary, in the anastomotic zone this phenomenon is not intense enough to jeopardize the anchorage of the suture thread since the original weft does not show any loss of compactness. In spite of surface morphological deterioration of various intensity, the suture threads maintain satisfactory mechanical properties and structural integrity. The artery wall in the anastomotic zone shows a massive degeneration in terms of its true anatomic structure responsible for the rupture of the suture rima. On the basis of these results the authors conclude that this phenomenon represents the "Achilles' heel" of anastomotic junction.

[Biodegradation of dacron vascular prostheses. Physico-chemical, histological, morphometric and ultrastructural study]. / Biodegradazione delle protesi vascolari in Dacron. Studio chimico-fisico, istologico, morfometrico ed ultrastrutturale.

The paper deals with study of long-term stability as far as concerns Dacron vascular prostheses in woven and knitted double velour. Among our vascular prostheses case-reports, we evaluated three of them explanted after 11, 12, 20 years; all of the prostheses were patent. Chemical-physical, histopathological and ultrastructural analysis have been carried on in order to evaluate in vivo ageing of the examined prostheses. The results all indicate strong alterations of the original properties related to double velour of knitted prostheses and weak alterations of woven one.

[Prognostic implications of the proliferation index (H3-TdR-labeling index) and ploidy in neuroectodermal tumors (astrocytomas and glioblastomas)]. / Implicazioni prognostiche dell'indice di proliferazione (3H-TdR-labeling index) e della ploidia nei tumori neuroectodermici (astrocitomi e glioblastomi).

Kinetic cellular methods were used in 53 cases of various sizes of astrocytomas and glioblastomas to obtain reliable prognostic information. Kinetic analysis revealed a wide variation of proliferative activity, with a gradual increase of the mean value from the most differentiated astrocytomas to glioblastomas. DNA content was significantly correlated with the degree of histological differentiation. Chromosomic patterns, which were detected in a few cases, were generally aspecific. The sole recurrent alteration in the karyotype was a small metacentric marker. The comparison of results obtained with the follow-up of patients showed that the labeling index offers a more accurate estimate of the proliferative potential of individual tumours, and thus of the probability of survival, than histological diagnosis and the evaluation of other biological parameters such as ploidy and karyotype.