Head and neck paragangliomas: Recent advances in translational and clinical research and guidelines for patient care.

Head and neck paragangliomas (HNPGLs), rare neuroendocrine tumors that mainly arise from parasympathetic ganglia along the cranial nerves, are challenging due to anatomic origin, tendency to aggressive neurovascular and skull base infiltration, unpredictable metastatic potential, radio-chemoresistance, and risk of multiplicity. Symptoms range from mild to life threatening depending on location/size, but rarely relate to catecholamine excess. Risk factors include female sex and pathogenic germline variants in genes affecting hypoxia signaling (foremost succinate dehydrogenase genes). Diagnostic work-up relies on imaging, measurements of plasma free metanephrines/methoxytyramine, genetic testing, and pathology/immunohistochemistry. Management is tailored to patient/tumor characteristics and encompasses wait-scan, upfront surgery, debulking surgery, and radiotherapy. Presurgical embolization is recommended, except for small tympanic and tympanomasoid tumors. Presurgical stenting is required for internal carotid artery involvement, and two-stage surgery for intradural extension. Current treatments for metastatic/inoperable HNPGL are non-curative, and long-term follow-up should be recommended for all patients to monitor local recurrence and new tumors.

Correction to: Paragangliomas arise through an autonomous vasculo-angio-neurogenic program inhibited by imatinib.

The given and family names of two co-authors were incorrect in the published article. The correct spelling should read as: Sampath Chandra Prasad and Vinagolu K Rajasekhar.

Paragangliomas arise through an autonomous vasculo-angio-neurogenic program inhibited by imatinib.

Tumours can be viewed as aberrant tissues or organs sustained by tumorigenic stem-like cells that engage into dysregulated histo/organogenetic processes. Paragangliomas, prototypical organoid tumours constituted by dysmorphic variants of the vascular and neural tissues found in normal paraganglia, provide a model to test this hypothesis. To understand the origin of paragangliomas, we built a biobank comprising 77 cases, 18 primary cultures, 4 derived cell lines, 80 patient-derived xenografts and 11 cell-derived xenografts. We comparatively investigated these unique complementary materials using morphofunctional, ultrastructural and flow cytometric assays accompanied by microRNA studies. We found that paragangliomas contain stem-like cells with hybrid mesenchymal/vasculoneural phenotype, stabilized and expanded in the derived cultures. The viability and growth of such cultures depended on the downregulation of the miR-200 and miR-34 families, which allowed high PDGFRA and ZEB1 protein expression levels. Both tumour tissue- and cell culture-derived xenografts recapitulated the vasculoneural paraganglioma structure and arose from mesenchymal-like cells through a fixed developmental sequence. First, vasculoangiogenesis organized the microenvironment, building a perivascular niche which in turn supported neurogenesis. Neuroepithelial differentiation was associated with severe mitochondrial dysfunction, not present in cultured paraganglioma cells, but acquired in vivo during xenograft formation. Vasculogenesis was the Achilles' heel of xenograft development. In fact, imatinib, that targets endothelial-mural signalling, blocked paraganglioma xenograft formation (11 xenografts from 12 cell transplants in the control group versus 2 out of 10 in the treated group, P = 0.0015). Overall our key results were unaffected by the SDHx gene carrier status of the patient, characterized for 70 out of 77 cases. In conclusion, we explain the biphasic vasculoneural structure of paragangliomas and identify an early and pharmacologically actionable phase of paraganglioma organization.

The Gruppo Otologico experience of endolymphatic sac tumor.

OBJECTIVE: Endolymphatic sac tumor (ELST) is a rare low grade adenocarcinoma of the skull base. During the past decade the number of the reported cases has increased. This study exposes our experience in the management of ELST with a review of the literature. STUDY DESIGN: Retrospective study of patients with ELST at a quaternary referral otology and skull base center. METHODS: A review of the records from the Gruppo Otologico revealed 7 patients treated for ELST. All papers containing series of three or more cases of ELST published in the English literature were selected for analysis. RESULTS: Hearing loss and tinnitus were present in almost all our cases. All of them were evaluated with audiometric tests, computed tomography and magnetic resonance imaging. All the patients were treated surgically with preservation of the facial nerve and preoperative embolization was performed in 5 patients. Genetic study was performed on all our cases and revealed the presence of von Hippel-Lindau syndrome in one patient who had the tumor as the initial manifestation of his syndrome. None of the patients received postoperative radiotherapy and one of them had recurrence of the tumor 13 years following surgery. CONCLUSIONS: Complete surgical resection with preoperative embolization of large tumors is the mainstay treatment for ELST. The facial nerve should not be sacrificed unless it is totally invaded by the tumor. A long term follow up is recommended and the role of postoperative adjunctive radiotherapy is still controversial.

Malignancy in vestibular schwannoma after stereotactic radiotherapy: a case report and review of the literature.

OBJECTIVES/HYPOTHESIS: A relation between conventional radiotherapy and the development of intracranial neoplasma is well known, but radiation-associated tumor following stereotactic radiotherapy of vestibular schwannoma is underestimated. In this article we will study this relation by doing a complete literature review on all the malignant intracranial tumors that appeared following radiosurgery and adding a case of malignant vestibular schwannoma following stereotactic radiotherapy in a Neurofibromatosis type 2 patient. METHODS: Literature review and discussion. RESULTS: We found 26 cases of malignant brain tumor following stereotactic radiotherapy including our case. In 13 cases the tumor occurred in context of Neurofibromatosis type 2. None of the patients had a tumor size less than 2.5 cm. and the mean latency period between the radiotherapy and malignant tumor development was 5.8 years. CONCLUSION: Patients with vestibular schwannoma should be made aware of the low incidence of the radiation-induced malignant changes and long-term follow-up is mandatory.

Naive HIV/HCV-coinfected patients have higher intrahepatic pro-inflammatory cytokines than coinfected patients treated with antiretroviral therapy.

In the era of antiretroviral therapy, liver disease has emerged as an important cause of morbidity and mortality in HIV/hepatitis C virus (HCV) coinfected patients. It is believed that HCV is a non-cytopathic virus and that T-cell-mediated events (including the production of pro-inflammatory cytokines) have an important role in promoting both liver damage and viral clearance. Whether HIV coinfection or antiretroviral therapies influence such events is still unclear. In the current study, we compared the expression of NKp46 (a natural killer cell marker), CD3 (a T-cell marker), interferon-gamma (IFN-gamma), tumour-necrosis factor-alpha (TNF-alpha; pro-inflammatory cytokines) and interleukin-10 (IL-10; an anti-inflammatory cytokine) mRNA in the liver of naive HIV/HCV-coinfected patients (group one, n=14), coinfected patients treated with antiretroviral therapy (group two, n=23) and naive HCV mono-infected patients (group three, n=24). All three groups had comparable HCV viremia, with coinfected patients showing similar and relatively high CD4+ T-cell counts and significantly different HIV vireamia. Interestingly, when compared to groups two and three, group one showed significantly higher intrahepatic mRNA levels for CD3, IFN-gamma and TNF-alpha, whereas the expression of NKp46 and IL-10 were comparable in all three groups. Further, higher histopathological grading scores within each group were independently associated with higher mRNA contents for CD3 and IFN-gamma and higher serum alanine aminotransferase levels at the time of liver biopsy. Together, these results suggest that HIV infection may exacerbate the immune-mediated inflammatory response in the liver of patients chronically infected with HCV and antiretroviral therapy may prevent this effect.

A relapsing inflammatory syndrome and active human herpesvirus 8 infection.

We describe an immunocompetent 61-year-old woman who was negative for human immunodeficiency virus and who had recurrent human herpesvirus 8 (HHV-8) infection associated with a relapsing systemic inflammatory syndrome characterized by fever, lymphadenopathy, splenomegaly, edema, arthrosynovitis, and rash. Kaposi's sarcoma developed 10 months after the initial clinical presentation. A correlation was documented between the recurrent clinical manifestations and the HHV-8 load in plasma and peripheral-blood mononuclear cells. Histologic examination of an enlarged lymph node heavily infected with HHV-8 revealed an atypical lymphoproliferative disorder characterized by paracortical hyperplasia and collapsed primary and secondary follicles.