Mature posterior fossa teratoma mimicking dermoid cyst.

We describe a very rare case of mature posterior fossa teratoma in an adult who presented with clinico-radiological findings consistent with a dermoid cyst. A computed tomography scan showed a hypodense mass in the cistern magna with calcification and a sinus tract in the occipital bone. Magnetic resonance imaging revealed a hypo- to hyperintense mass without contrast enhancement. The intraoperative picture showed a dermal sinus and a cyst containing lipid, keratin and hair. Histopathological examination showed a tumor with components of all the three germ layers; thereby, a diagnosis of mature teratoma was made. The histopathological differentiation between teratoma and dermoid cyst is very valuable for ruling out the presence of immature/malignant or germinomatous components that would require further adjuvant therapies. Thus, we here present a rare case of posterior fossa teratoma mimicking dermoid cyst and emphasize the importance of histopathological differentiation between these entities.

Reward Contingency Modulates Neuronal Activity in Rat Septal Nuclei during Elemental and Configural Association Tasks.

It has been suggested that septal nuclei are important in the control of behavior during various reward and non-reward situations. In the present study, neuronal activity was recorded from rat septal nuclei during discrimination of conditioned sensory stimuli (CSs) of the medial forebrain bundle associated with or without a reward (sucrose solution or intracranial self-stimulation, ICSS). Rats were trained to lick a spout protruding close to the mouth just after a CS to obtain a reward stimulus. The CSs included both elemental and configural stimuli. In the configural condition, the reward contingency of the stimuli presented together was opposite to that of each elemental stimulus presented alone, although the same sensory stimuli were involved. Of the 72 responsive septal neurons, 18 responded selectively to the CSs predicting reward (CS(+)-related), four to the CSs predicting non-reward (CS(0)-related), nine to some CSs predicting reward or non-reward, and 15 non-differentially to all CSs. The remaining 26 neurons responded mainly during the ingestion/ICSS phase. A multivariate analysis of the septal neuronal responses to elemental and configural stimuli indicated that septal neurons encoded the CSs based on reward contingency, regardless of the stimulus physical properties and were categorized into three groups; CSs predicting the sucrose solution, CSs predicting a non-reward, and CSs predicting ICSS. The results suggest that septal nuclei are deeply involved in discriminating the reward contingency of environmental stimuli to manifest appropriate behaviors in response to changing stimuli.

Delayed tentorial herniation after crainoplasty with polymethylmethacrylate: a rare complication.

We report the case of a 49-year-old man who underwent a craniectomy for severe head trauma and subsequent cranioplasty with polymethylmethacrylate. He was discharged with moderate right-hand weakness. Five years after the cranioplasty he experienced double vision and slight right hemiparesis. Magnetic resonance imaging (MRI) revealed signs of tentorial herniation but no specific space-occupying lesions. The hand-moulded polymethylmethacrylate bone flap was found to be uneven and protrusions on the inner surface of the bone graft slightly compressed the brain below. His symptoms improved dramatically after a second cranioplasty using a ceramic implant. Although some complications including infection and cosmetic problems have been reported, tentorial herniation during late follow-up as a specific complication of cranioplasty has not been documented previously. We attribute his neurological improvement to the release of compression from the initial graft and to the consequent restoration of cerebrospinal fluid dynamics.

Histone deacetylase inhibitor, FK228, induces apoptosis and suppresses cell proliferation of human glioblastoma cells in vitro and in vivo.

We investigated the effects of FK228 on cell proliferation and apoptosis against human glioblastoma (GM) T98G, U251MG, and U87MG cells. Upon exposure to FK228, cell proliferation was inhibited, and apoptosis detected by the cleavage of CPP32 was induced. FK228 increased the expression levels of p21 (WAF-1) and of pro-apoptotic Bad protein in all GM cells. Furthermore, FK228 treatment also reduced the anti-apoptotic protein Bcl-xL in all GM cells and anti-apoptotic Bcl-2 in U87MG cells, thereby shifting the cellular equilibrium from life to death. An increased accumulation of histone H4 was detected in the p21 (WAF-1) promoter and the structural gene (exon 2) and the Bad structural gene (exon 2 and 3) upon treatment with FK228, as assessed by chromatin immunoprecipitation (ChIP) assay. Thus, the results indicated that an increased expression of p21 (WAF1) and Bad due to FK228 is regulated, at least in part, by the degree of acetylation of the gene-associated histone. We also found that FK228 inhibits cellular invasiveness and decreases MMP-2 activity. In addition, the growth of transplanted human GM m-3 cells into the subcutaneous tissue of hereditary athymic mice was significantly inhibited, and apoptosis was induced with FK228 treatment. The results suggested that FK228 might be useful in the treatment of human GM, although further studies will be needed.