Pediatric Langerhans cell histiocytosis: the impact of mutational profile on clinical progression and late sequelae.

Langerhans cell histiocytosis (LCH) is a clonal histiocytic disorder with recurrent mutations of BRAF and MAP2K1, but data on the impact of genetic features on progression and long-term sequelae are sparse. Cases of pediatric LCH with long-term follow-up from our institution were analyzed for mutations in BRAFV600 and MAP2K1 exons 2 and 3 by immunostaining with mutation-specific VE1 antibody, as well as allele-specific PCR and sequencing, respectively. Clinical and follow-up data were obtained from our files and a questionnaire sent to all former patients. Sixteen of 37 (43%) evaluable cases showed BRAFV600E, one case a BRAFV600D and eleven (30%) a MAP2K1 mutation. Nine cases were unmutated for both genes. All cases with risk organ involvement showed either BRAFV600 or MAP2K1 mutation. Patients with BRAFV600 mutation excluding Hashimoto-Pritzker cases had a significantly higher risk for relapses (p = 0.02). Long-term sequelae were present in 19/46 (41%) patients (median follow-up 12.5 years, range 1.0 to 30.8) with a trend for higher rates in mutated cases (mutated = 9/17, 53% versus non-BRAFV600/MAP2K1 mutated = 2/7, 29%). In addition, 8/9 cases with skin involvement including all Hashimoto-Pritzker cases (n = 3) were positive for BRAFV600E. Infants below 2 years more frequently had BRAFV600 mutations (p = 0.013). Despite favorable prognosis, pediatric LCH shows a high frequency of relapses and long-term medical sequelae.

CD74 regulates complexity of tumor cell HLA class II peptidome in brain metastasis and is a positive prognostic marker for patient survival.

Despite multidisciplinary local and systemic therapeutic approaches, the prognosis for most patients with brain metastases is still dismal. The role of adaptive and innate anti-tumor response including the Human Leukocyte Antigen (HLA) machinery of antigen presentation is still unclear. We present data on the HLA class II-chaperone molecule CD74 in brain metastases and its impact on the HLA peptidome complexity.We analyzed CD74 and HLA class II expression on tumor cells in a subset of 236 human brain metastases, primary tumors and peripheral metastases of different entities in association with clinical data including overall survival. Additionally, we assessed whole DNA methylome profiles including CD74 promoter methylation and differential methylation in 21 brain metastases. We analyzed the effects of a siRNA mediated CD74 knockdown on HLA-expression and HLA peptidome composition in a brain metastatic melanoma cell line.We observed that CD74 expression on tumor cells is a strong positive prognostic marker in brain metastasis patients and positively associated with tumor-infiltrating T-lymphocytes (TILs). Whole DNA methylome analysis suggested that CD74 tumor cell expression might be regulated epigenetically via CD74 promoter methylation. CD74high and TILhigh tumors displayed a differential DNA methylation pattern with highest enrichment scores for antigen processing and presentation. Furthermore, CD74 knockdown in vitro lead to a reduction of HLA class II peptidome complexity, while HLA class I peptidome remained unaffected.In summary, our results demonstrate that a functional HLA class II processing machinery in brain metastatic tumor cells, reflected by a high expression of CD74 and a complex tumor cell HLA peptidome, seems to be crucial for better patient prognosis.

Notch receptors in human choroid plexus tumors.

Notch signaling plays a role in development and formation of the normal choroid plexus (nCP), and in formation of various tumors in humans. Activation of Notch3 has been reported to promote tumor growth in invasive gliomas and to initiate formation of choroid plexus tumors (CPT) in mice. We investigated the expression of all currently known Notch receptors (Notch 1-4) in 55 samples of nCP and 88 CPT, including 61 choroid plexus papillomas (CPP), 22 atypical CPP and 5 choroid plexus carcinomas by immunohistochemistry. Notch expression was semiquantitatively evaluated separately for membranous/cytoplasmic and for nuclear staining. In addition, we examined Her2 expression (EGFR2, Her2/neu, ErbB2, CD340) because of its functional link to Notch signaling. All samples were negative for Notch3. Membranous/cytoplasmic expression of Notch1 (p<0.0001) and Notch4 (p=0.046) was significantly higher, whereas Notch2 expression was significantly lower (p<0.0001) in nCP compared to CPT. Nuclear expression of Notch1, -2 and -4 was significantly higher in CPT compared to nCP (p<0.0001 each). Expression of Notch2 and Notch4 showed a shift from a prevailing membranous/cytoplasmic expression in nCP to a predominant nuclear expression in CPT. Her2 was weakly expressed in 42/84 CPT but only in 2/53 nCP (p=0.0001) and positively correlated with nuclear expression of Notch1, -2 and 4 in CPT. In summary, a shift between membranous/cytoplasmic (non-canonical signaling pathway) and nuclear expression (canonical signaling pathway) of Notch1, -2 and -4 and upregulation of Her2 indicate neoplastic transformation in human CP and may reveal new therapeutic approaches.

Common and uncommon imaging findings in progressive multifocal leukoencephalopathy (PML) with differential diagnostic considerations.

OBJECTIVE: To provide a practical review of the spectrum of possible imaging findings in patients with progressive multifocal leukoencephalopathy (PML) and to address differentials. CONCLUSION: PML manifests with a broad spectrum of imaging features. Besides knowledge of preferential location, extent, temporal course, enhancement, results of functional imaging and clinical setting, recognition of imaging findings reflecting active demyelination may help the clinician in appropriately narrowing down the differential diagnosis.

T2 and DWI in pilocytic and pilomyxoid astrocytoma with pathologic correlation.

OBJECTIVE: To quantify and compare T2 signal and apparent diffusion coefficient (ADC) in pilocytic and pilomyxoid astrocytoma (PA and PMA) and correlate results with myxoid content. METHODS: Echo-planar diffusion weighted images (DWI) and standard magnetic resonance imaging (MRI) findings were reviewed retrospectively in patients with PA (n=34) and PMA (n=8). Regions of interest (ROIs) were drawn on ADC maps within tumor parts with lowest ADC values. Apparent diffusion coefficient values in tumor were normalized to those in cerebrospinal fluid (ADC/CSF). The ratio of T2 signal intensity in solid tumor parts to CSF (T2/CSF) was registered. Myxoid matrix was histologically quantified retrospectively in 8 PMAs and 17 PAs and correlated with imaging findings. RESULTS: Mean ADC/CSF for PA and PMA was 0.53±0.10 and 0.69±0.10 (p<0.01). Mean T2/CSF for PA and PMA was 0.78±0.19 and 0.93±0.09 (p<0.01). Mean proportion of myxoid tumor matrix in PA was 50% (range, 10-100%) and 93% (range, 90-100%) in PMA (p=0.004). Eight patients (32%; all PA) had less than 50% myxoid content and 17 (68%; 8 PA; 9 PMA) had more. There was positive correlation of ADC/CSF, T2/CSF and ADC (r2=0.61, 0.65 and 0.60 respectively) and significant difference between the groups with more and less than 50% myxoid content (p=0.01 for ADC/CSF and T2/CSF and p=0.02 for ADC). CONCLUSIONS: General imaging features of PA and PMA are non-specific, ADC values and T2 signal intensity are generally higher in the latter, reflecting the proportion of myxoid matrix in these tumors.

Pituicytoma in a patient with Cushing's disease: case report and review of the literature.

Pituicytoma is an exceptionally rare low-grade glioma (WHO grade I) of the neurohypophysis and infundibulum. We are reporting the case of a 48-year-old man who presented with severe Cushing's syndrome. Endocrinological evaluation unequivocally confirmed pituitary-dependent Cushing's syndrome (=Cushing's disease). Cranial MR-imaging displayed a conspicuous area in the dorsal and basal pituitary gland and a minimal bulging of the pituitary gland paramedian of the pituitary stalk on the right side. Transsphenoidal inspection revealed a small tumor in the basal and dorsal pituitary gland. Surprisingly, the definite postoperative histopathological diagnosis of the removed tumor was pituicytoma and not pituitary adenoma. Hence, the microadenoma responsible for Cushing's disease was not yet removed and persistent hypercortisolism necessitated transsphenoidal re-operation. During re-operation, hemihypophysectomy was performed on the right side. The non-tumorous specimen of the adeno-hypophysis showed signs of Crooke's hyalinization consistent with Cushing's disease. Undetectable postoperative ACTH- and cortisol levels provided clear evidence that the underlying ACTH-source was successfully removed during re-operation. Coincidence of pituicytoma and pituitary-dependent Cushing's disease has not previously been reported.

De novo expression of the hemoglobin scavenger receptor CD163 by activated microglia is not associated with hemorrhages in human brain lesions.

The main function of CD163 (hemoglobin scavenger receptor) is to bind the hemoglobin-haptoglobin complex, thereby mediating extravasal hemolysis. However, CD163 also has an antiinflammatory function. After CD163-mediated endocytosis, hemoglobin is catabolized further by hemeoxygenase 1 (HO-1). Previously, we found expression of HO-1 to be restricted to microglia/macrophages at sites of hemorrhages in human traumatic and ischemic brain lesions. We now investigated if CD163 expression is also correlated with hemorrhages in brain lesions. Methods. Autopsy brain tissue from 44 cases with hemorrhagic brain lesions (32 traumatic brain injuries/TBI, 12 intracerebral bleedings/ICB), 56 non-hemorrhagic brain lesions (30 ischemias, 26 hypoxias) and 6 control brains were investigated. The post injury survival times ranged from a few minutes to 60 months. Results. In controls, single perivascular monocytes expressed CD163, but only single CD163+ microglia were found in 3/6 cases. CD163+ cells in the parenchyma (activated microglia/macrophages) increased significantly within 24 hours after trauma and ischemia and within 1-7 days following ICB or hypoxia. Overall, significantly lower and higher levels of parenchymal CD163+ cells occurred in hypoxia and ischemia, respectively. Perivascular CD163+ cells also increased significantly in all pathological conditions. In areas remote from circumscribed brain lesions (TBI, ICB, ischemia), significant changes were only found in ICB and ischemia. Conclusions. De novo expression of CD163 by activated microglia/macrophages and CD163+ infiltrating monocytes are neither restricted to nor predominant in hemorrhagic brain lesions. Thus, the antiinflammatory function of CD163 probably predominates, both in hemorrhagic and non-hemorrhagic brain lesions and points to possible immunomodulatory treatment strategies targeting CD163.

Erythropoietin receptor expression in normal and neoplastic choroid plexus.

BACKGROUND: The erythropoietin receptor (EpoR) is expressed widely throughout the human CNS, including the choroid plexus. Recent studies have shown that EpoR is also expressed in various human tumors, including carcinomas, meningiomas and gliomas. Thereby, the Epo-EpoR pathway plays a role in inhibition of apoptosis and tumor growth, infiltration, angiogenesis and metastasis as well as treatment resistance and is a potential target in oncological treatment. Lower levels of EpoR have been associated with shorter survival in high grade gliomas and higher risk of tumor recurrence in meningiomas. METHODS: Since the EpoR status in human choroid plexus tumors (CPT) is not known, we investigated 57 CPT from 43 cases including 14 recurrent tumors and compared them with 23 samples of normal choroid plexus (CP). CPT samples consisted of choroid plexus papillomas/CPP (n = 41), atypical CPP (n = 15) and choroid plexus carcinoma/CPC (n = 1). EpoR expression was determined by immunohistochemistry using semi-quantitative scoring for staining intensity and was validated in exemplary cases using western blot and RT-PCR. RESULTS: EpoR expression was observed in all samples of normal and neoplastic CP with significantly lower expression levels in CPT (p < 0.001). CONCLUSION: No significant correlation was found between EpoR expression and age, gender, WHO grade, number of mitosis or tumor recurrence. EpoR expression in CPT is in line with its expression in normal CP and with previous reports on EpoR expression in other glial neoplasms. Association of EpoR levels in CPT with survival, as known in astrocytic gliomas, remains to be determined.

Spinal pilocytic astrocytoma: MR imaging findings at first presentation and following surgery.

OBJECTIVE: The objective of this article is to describe MR imaging findings of spinal cord pilocytic astrocytomas at first presentation and following neurosurgery and to discuss briefly some of the most common differential diagnoses. CONCLUSION: MR imaging findings in medullary pilocytic astrocytomas consist generally of focal or diffuse cord-enlarging masses that are irregularly shaped, accompanied by cystic elements and hydromyelia, present different degrees of contrast enhancement, high water diffusivity and a propensity for the thoracic and cervical cord.

Benign meningioma developing late lung metastases: case report and review of the literature.

Here we report the case of a 65-year-old female with a histologically benign parietal falcine meningioma who developed multiple lung metastases 15 years after tumor resection. The meningioma was initially incompletely resected due to invasion of the sagittal sinus. Since it was diagnosed as a benign meningothelial meningioma Grade I WHO, the residual tumor was followed with serial imaging without adjuvant treatment. The patient subsequently developed lung lesions later identified as metastases. The lung lesions were successfully removed surgically and histologically diagnosed as meningothelial meningioma Grade I WHO. A repeat brain MRI revealed the known residual meningioma with no signs of interval tumor growth, but did demonstrate occlusion of the sagittal sinus. In the further course, the residual meningioma was completely removed. A review of the literature revealed only 15 well-documented cases of benign meningiomas that metastasized in an interval of up to 12 years after primary tumor resection. This case illustrates that histologically benign meningiomas Grade I WHO with stable disease of the primary tumor have the potential to develop hematogenous metastases even after a long time interval.

Immunohistochemical analysis of CDX2 expression in normal choroid plexus epithelium and choroid plexus tumors.

BACKGROUND: The Wnt and BMP signaling pathways are involved in the morphogenesis of both gastrointestinal and choroid plexus epithelium. In the intestine, Wnt signaling represses the expression of the tumor suppressor gene CDX2 via SOX9, a transcription factor, which is also expressed in the choroid plexus. Recently, an inverse correlation between CDX2 expression and tumor grade, tumor stage and lymph node metastasis in colorectal adenocarcinomas has been reported. Besides intestinal tissues, expression of CDX2 has also been reported in various other epithelial tissues and carcinomas. To date, no data exist on expression of CDX2 in normal and neoplastic choroid plexus epithelium. AIM: To investigate CDX2 expression in normal and neoplastic choroid plexus. MATERIALS AND METHODS: Paraffin-embedded samples from 60 normal choroid plexus, including 23 fetal tissue samples and from 65 choroid plexus tumors (47 choroid plexus papillomas WHO grade I, 16 atypical choroid plexus papillomas and 2 choroid plexus carcinomas WHO grade III) were examined by immunohistochemistry. Samples from normal choroid plexus were collected from 45 autopsy cases and from 15 neurosurgical specimens. RESULTS: Normal and neoplastic choroid plexus lacked CDX2 expression. CONCLUSION: In our series, immunohistochemistry shows no evidence for a role of CDX2 in development or differentiation of normal choroid plexus from the 9th gestational week until adulthood. Since choroid plexus tumors reliably lack CDX2 immunoreactivity, this marker may be helpful in distinguishing cerebral metastases from CDX2-positive adenocarcinomas and choroid plexus neoplasms.

Sellar neuroblastoma mimicking a pituitary tumour: case report and review of the literature.

Neuroblastomas of the sellar region are exceedingly rare. Only 2 cases have previously been reported. Management of these tumours depends on the tumour's primary site, the patient's age and histopathological features. We are reporting the case of a 43-year-old woman who developed progressive bitemporal hemianopsia and visual loss, accompanied by amenorrhea and hyponatremia. Laboratory findings revealed a slightly elevated prolactin level. Cranial MR-imaging displayed an intrasellar and suprasellar lesion with a maximum diameter of 2.5 cm that was suspicious for a pituitary adenoma or tuberculum sellae meningioma. The tumour was approached via a pterional trepanation. Intraoperatively, the tumour was highly vascularized and adhesive to the optic chiasm, the floor of the third ventricle, the hypothalamus and the hypophyseal stalk. Postoperatively, vision improved and prolactin dropped to normal values, but hyponatremia persisted. Histopathological examination revealed a neuroblastoma with strong positivity for synaptophysin and chromogranin, MAP-2 protein and NeuN-antigen in the immunohistochemistry. No pituitary hormone receptors were expressed. The MIB-1 labelling index was positive in 5% of the cell nucleoli. In the further course, the patient underwent radiotherapy of the neuroaxis. A brief review of the literature is presented.

No evidence for WT1 involvement in a beta-catenin-independent activation of the Wnt signaling pathway in pituitary adenomas.

The overexpression of Wilms' tumor gene product WT1, which acts as a tumor suppressor or oncogene, has been reported in various malignancies. Recent studies have shown that the interaction partner Wnt-4 is upregulated in pituitary adenomas dependent on the Pit-1 lineage (somatotrophs, lactotrophs, and thyrotrophs). However, no data on WT1 expression in nontumorous pituitary tissue or pituitary adenomas is available to date. We investigated WT1 expression in 90 paraffin-embedded pituitary adenomas, including eight atypical adenomas, and in 28 nontumorous pituitary glands by immunohistochemistry. WT1 is absent in epithelial cells of all nontumorous pituitary glands and in 87 out of 90 pituitary adenomas. Only two GHomas (including one atypical adenoma) and one gonadotropin-producing adenoma expressed WT1 in the cytoplasm of single tumor cells without nuclear staining. There is no evidence that WT1 does regulate the Wnt-4/beta-catenin-independent pathway which is activated in the Pit-1-expressing subset of pituitary adenomas.

Outcome of transanal endorectal pull-through in patients with Hirschsprung's disease.

INTRODUCTION: Various outcomes following transanal endorectal pull-through (TERPT) in patients with Hirschsprung's disease (HD) have been reported. In this study, the postoperative course and functional outcome after TERPT in 25 patients with HD is evaluated. METHODS: Patient records of children who underwent TERPT for HD between 2002 and 2007 were reviewed retrospectively. Age at surgery, sex, associated malformations, length of follow-up, presence of colostomy, indication for laparotomy, length of the aganglionic segment, result of rectal examination under general anaesthesia 6 weeks after surgery, necessity of a dilatation program or reoperation were investigated. In addition, standardised interviews were performed to collect the following data: bowel movement per day, faecal continence in potty-trained children or in patients older than 3 years, incidence of diarrhoea or problems with micturition and the necessity for laxative therapy. RESULTS: Between 2002 and 2007, 25 patients underwent TERPT for HD. Median age at the time of surgery was 3.5 months. Median follow-up was 35 months. Calibration of the anus showed a normal age-related diameter of the anus in 12/20 children and a markedly reduced diameter in 8/20 children at 6 weeks postoperatively. Seven of the latter children underwent a dilatation program. A redo pull-through procedure was performed in 3 patients due to stenosis at the colo-anal anastomosis (n=1), a constricting muscle cuff (n=1) and a twisted pull-through (n=1). Two children developed enterocolitis. The median frequency of bowel movements was 3/day (1-5/day). Laxative treatment was required in only one patient (4.5%). None of the patients had diarrhoea. Nineteen children (86%) were potty-trained, being older than 3 years. Eighteen of them were continent (95%). One patient (5%) with trisomy 21 suffered from intermittent non-retentive faecal incontinence. None of the patients showed signs of neurogenic bladder dysfunction. CONCLUSION: The functional outcome in most patients after TERPT is satisfactory. We suggest that routine rectal digital examination and anal calibration under anaesthesia 6 weeks postoperatively might detect occult anodermal stenosis and allow early initiation of an anorectal dilatation program, which could decrease the incidence of enterocolitis, persistent constipation and the necessity for further surgical intervention.