Cerebellar liponeurocytoma with atypical histological features - a rare example of a glioneuronal tumor.

We present a case of a rare neoplasm in a 77-year-old woman with previous oncological history, who developed a rapid onset of cerebellar symptoms. The neuroimaging detected a posterior fossa tumor suspected of meningioma which was completely resected soon after. Histologically the neoplasm had two components with different immunophenotype. One constituent was lobular, composed of monotonous mitotically active round cells with a predominant neuronal profile. The second, astrocytic component contained lipomatous cells intermixed with larger gemistocytic astrocytes. Fields of geographic necrosis as well as multifocal microvascular proliferation were observed. The Ki67 proliferation index was 12%. After two years of follow-up the patient remains free of symptoms and radiologic recurrence. The presented case of cerebellar liponeurocytoma is unusual in terms of its atypical histological features and prominent astrocytic component. The authors propose that the term 'lipomatous glioneuronal tumor' seems to be more appropriate for this type of lesion, considering its histologic spectrum and possible extracerebellar location.

Extracardiac rhabdomyomas--presentation of two cases with analysis of AKT/mTOR and ERK1/2 signaling.

Extracardiac rhabdomyomas (RM) are very rare benign tumors with a poorly understood pathogenesis. In this report we describe two RM cases--a sublingual adult type tumor and a genital type tumor involving the uterine cervix. The patho-clinical characteristics, as well as the pioneer immunohistochemical analysis of ERK1/2 and AKT/mTOR pathway status is included. The expression of key proteins involved in above signaling gives new insight into the biology of extracardiac RM.

Proliferation index revisited in neuroblastic tumors.

Neuroblastic tumors (NB) are the most common extracranial pediatric neural crest-derived tumors, with a dismal outcome in a substantial group of patients. The study objective was to evaluate the patho-clinical correlations and prognostic impact of the proliferation index (PI) measured with two markers, Ki67 and topoisomerase II alpha (Topo2A), in a NB series. A retrospective analysis of 118 NB from 103 consecutive patients was performed. Analyzed data included tumor stage, histology, mitosis/karyorrhexis index (MKI), MYCN status, and overall survival. Patients' median follow-up period was 50 months. Ki67 and Topo2A PI were assessed immunohistochemically on representative tissue slides in hot spots. PI for Ki67 was in the range 0-72% (median 18%) and for Topo2A was in the range 0-58% (median 20%), being strongly interrelated (r = 0.83). Median PIs with both markers were lower in children older than 18 months (> 18 m) than in the younger patients, with p = 0.0002 and p = 0.005 respectively. Higher Ki67 and Topo2A correlated with metastatic stage, higher MKI, and inversely with increasing tumor differentiation. The cut-off values of PI Ki67 > 30% and Topo2A > 20% were associated with fatal outcome of the disease. In the subgroup of patients > 18 m already at cut-offs Ki67 > 10% and Topo2A > 15% a fatal outcome was predicted by Kaplan-Meyer analysis. Cox regression analysis identified cumulative PI (joint Ki67 and Topo2A index) as an independent prognostic factor. The conclusion is that the proliferation index measured with the examined markers provides substantial prognostic information in NB, especially in infants. PI assessment should become an element of the standard pathological checkup list of NB tumors.