Treatment of very large cranial defects with individually shaped polypropylene polyester knitwear prostheses: a series of 11 cases.

BACKGROUND: Very large cranial defects are not very common in neurosurgical practice and there is not any widely acknowledged standard of their treatment. One of the useful methods in such cases is individual forming of polypropylene-polyester knitwear. Such material was used in the past but before 2008 it was available only as standardized plates. Currently, it can be also produced as individually-shaped implants. The authors give their definition of very large cranial defects and present their experience with this cranioplastic method in such defects. METHODS: The authors collected data on 11 cases of patients with very large cranial defects, from a total of 156 cases, operated on in 5 Polish neurosurgical departments. The necessary implants were prepared for individual patients according to the data provided by a computed tomography examination and with the use of computer aided machining. RESULTS: All defects were larger than 120 cm2 (129 to 178 cm2) and exceeded 1/4 of the calvaria area. Patients were operated between 2008 to 2012. In all patients, a very good aesthetic result and correct skull reconstruction was achieved. The follow-up time in all cases exceeded 1 year and reached 4 years in one case. No complications were observed. CONCLUSIONS: Individually pre-shaped polypropylene-polyester knitwear prostheses are a good alternative to the existing cranioplasty methods, particularly in very large cranial defects.

Ultrastructure of meningiomas: autophagy is involved in the pathogenesis of "intranuclear vacuoles".

We report here common ultrastructural findings in a short list of meningiomas. At the lower power magnification, a tumour consisted of elongated or round cells and innumerable cellular processes connected with diverse intercellular junctions. Nuclei presented no specific features, nucleoli were infrequently seen and heterochromatin was clumped beneath the nuclear membranes. In a case of clear cell meningioma, cells were of watery cytoplasm. Occasionally, immobile cilia, completely ensheathed by the cytoplasm and anchored by blepharoplasts were seen; as we did not encounter those rare cilia in cross-sections, no further insight into their inner microtubular-doublet structure was possible. The cytoplasm of the cells and the processes were filled with the intermediate filaments. In the intercellular space, collagen fibrils and electron-dense material was occasionally observed. The majority of the tumour samples were filled with processes. Several types of junctional complexes were observed. The most frequent were desmosomes and in the proper plane of section their whole pentalaminar structure was readily discernible. However, robust tonofilaments, as seen in epithelial neoplasms, were not observed. Those desmosomal junctions were either completely symmetric or asymmetric, but the exact symmetry could not be judged without the assistance of a goniometer. Some junctional complexes were more elaborate, with desmosomal junctions separated by a tight apposition of membranes, which suggests tight junctions. "Intranuclear vacuoles" well-visible even at low power were defined as indentation of the cytoplasm into the nucleus. Within these vacuoles, autophagic vacuoles and lysosomal bodies were seen, suggesting an active macroautophagy process. In 2 cases, severe lipidization of meningioma cell cytoplasm was observed. In a case of anaplastic meningioma, a mitotic figure was found. In another case, empty rectangular spaces in the cytoplasm, suggestive of pre-existing crystalloid structures, were seen.

Prevalence of mutated TP53 on cDNA (but not on DNA template) in pleomorphic xanthoastrocytoma with positive TP53 immunohistochemistry.

Pleomorphic xanthoastrocytoma (PXA) is a tumor of astrocytic lineage that may have anaplastic features; such a phenotype usually correlates with a less favorable outcome. The molecular profile of PXA differs from other astrocytic tumors, but the molecular mechanisms of its formation and progression are still undefined. We analyzed a loss of heterozygosity and mutations of the SMARCB1 (also known as SNF5 or INI1) and TP53 genes in four cases of PXA. In just one case a TP53 mutation (Cys238Tyr) was readily detectable at the mRNA level, but it was almost undetectable during DNA sequencing. This case was also the only one exhibiting anaplastic features and TP53 overexpression as defined by immunohistochemistry. This observation supports our earlier findings on discrepancies in TP53 status in glioblastomas. We suggest that the incidence of TP53 mutations in pleomorphic xanthoastrocytoma may be underestimated and that molecular approaches should be used for greater diagnostic precision.