Clinical features,radiological profiles,pathological features and surgical outcomes of pituicytomas:a report of 11 cases and a pooled analysis of individual patient data

Background:Pituicytoma is an extremely rare low-grade glial tumor that is closely related to the neurohypophysis axis.Most studies of pituicytomas include only several cases.To better understand this disease,we reviewed a series of cases of pituicytomas.The diagnosis and treatment of pituicytoma must be further elucidated.Methods:Eleven patients with pituicytoma admitted to Beijing Tiantan Hospital from 2012 to 2019 were selected.The clinical features,including radiological and histological examination,surgical records and prognosis were reviewed.Sixty-eight other previously published cases of pituicytoma also were used to analyze the predictive factors for the results.The Cox regression model was used for univariate and multivariate analyses.Results:Our patients included 5 males(45.5%)and 6 females(54.5%),with a mean age of 49.3 years.The tumor was located in the suprasellar region in 5 patients(45.5%),intrasellar region in 4 patients(36.4%),and intrasellarsuprasellar region in 2 patients(18.2%).All patients were misdiagnosed with other common tumors in the sellar region before the operation.During the operation,gross total resection(GTR)of the tumor was achieved in 6 patients(54.5%),and subtotal resection(STR)was achieved in 5 patients(45.5%).The mean progression-free survival(PFS)time was 29.82 months.Tumor progression after surgical resection occurred in 4 patients(36.4%).Among them,60.0%of the patients(cases 4,5,7)with STR experienced progression,while 16.7%of the patients(case 2)with GTR experienced progression.Combined with the 68 cases in the literature,GTR was an independent risk factor for PFS time(P<0.05).Conclusions:Pituicytomas are more common in middle-aged people and the sellar region.The clinical manifestations of pituicytomas are different,but no diagnostic clinical features have been identified other than an abnormally abundant blood supply.Currently,GTR is the best approach for the treatment of pituicytomas.More patients and longer follow-up periods were needed to further elucidate the biological features of pituicytomas.

Ruin Probabilities for a Two-Dimensional Perturbed Risk Model with Stochastic Premiums

In this paper, we consider a two-dimensional perturbed risk model with stochastic premiums and certain dependence between the two marginal surplus processes. We obtain the Lundberg-type upper bound for the infinite-time ruin probability by martingale approach, discuss how the dependence affects the obtained upper bound and give some numerical examples to illustrate our results. For the heavy-tailed claims case, we derive an explicit asymptotic estimation for the finite-time ruin probability.

Statistical Inference for the Covariates-driven Binomial AR(1)Process

The binomial autoregressive(BAR(1))process is very useful to model the integer-valued time series data defined on a finite range.It is commonly observed that the autoregressive coefficient is assumed to be a constant.To make the BAR(1)model more practical,this paper introduces a new random coefficient binomial autoregressive model,which is driven by covariates.Basic probabilistic and statistical properties of this model are discussed.Conditional least squares and conditional maximum likelihood estimators of the model parameters are derived,and the asymptotic properties are obtained.The performance of these estimators is compared via a simulation study.An application to a real data example is also provided.The results show that the proposed model and methods perform well for the simulations and application.