Complexity of PEComas : Diagnostic approach, molecular background, clinical management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[Complexity of PEComas : Diagnostic approach, molecular background, clinical management (German version)]. / Komplexität von PEComen : Diagnose, Molekulargenetik, klinisches Management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

Lower exposure rates of partially absorbable mesh compared to nonabsorbable mesh for cystocele treatment: 3-year follow-up of a prospective randomized trial.

INTRODUCTION AND HYPOTHESIS: In surgery for pelvic organ prolapse (POP) the use of alloplastic meshes has become common. Among possible complications, mesh exposure is the most frequent problem. It is hypothesized that exposure rates are correlated to mesh weight and the amount of foreign material. Therefore, we conducted a prospective open-label randomized multicenter trial comparing a conventional polypropylene mesh (PP) with a partially absorbable polypropylene mesh (PA) for cystocele treatment. METHODS: A total of 200 patients with POP > stage I were randomized either to a conventional or a partially absorbable mesh. Exposure rates were observed after 3, 12, and 36 months and correlated to mesh material, patient characteristics, intraoperative data, and treatment centers. Furthermore, management of mesh exposure, satisfaction with surgery, and postoperative pain were evaluated. RESULTS: At all follow-up intervals mesh exposure rate was smaller in the group of the partially absorbable mesh (3 months PP 11.3 % vs PA 3.2 %, p=0.0492; 12 months 6.6 % vs 6.3 %; 36 months 7.5 % vs 3.4 %). Over the course of time, mesh exposure was observed in 27 patients, with surgical intervention necessary in 11 patients. The rate of recurrent POP was higher (p>0.05) in patients with the partially absorbable mesh. The majority of patients were fully satisfied with the operation (52.8 %) and had no pelvic floor pain (67.5 %). CONCLUSION: In this prospective, randomized trial with a long-term follow-up there was a low exposure rate in both treatment groups with a trend toward fewer exposures in the group of the partially absorbable mesh.

Use of cryostat sections from snap-frozen nervous tissue for combining stereological estimates with histological, cellular, or molecular analyses on adjacent sections.

Adequate tissue preparation is essential for both modern stereological and immunohistochemical investigations. However, combining these methodologies in a single study presents a number of obstacles pertaining to optimal histological preparation. Tissue shrinkage and loss of nuclei/nucleoli from the unprotected section surfaces of unembedded tissue used for immunohistochemistry may be problematic with regard to adequate stereological design. In this study, frozen cryostat sections from hippocampal and cerebellar regions of two rat strains and cerebellar and cerebral regions from a human brain were analyzed to determine the potential impact of these factors on estimates of neuron number obtained using the optical disector. Neuronal nuclei and nucleoli were clearly present in thin sections of snap-frozen rat (3 microm) and human (6 microm) tissue, indicating that neuronal nuclei/nucleoli are not unavoidably lost from unprotected section surfaces of unembedded tissue. In order to quantify the potential impact of any nuclear loss, optical fractionator estimates of rat hippocampal pyramidal cells in areas CA1-3 and cerebellar granule and Purkinje cells were made using minimal (1 microm) upper guard zones. Estimates did not differ from data reported previously in the literature. This data indicates that cryostat sections of snap-frozen nervous tissue may successfully be used for estimating total neuronal numbers using optical disectors.