Molecular profile of tumors with oligodendroglial morphology: Clinical relevance.

BACKGROUND: The plethora of biomarkers available for the diagnosis and prognostication of gliomas has refined the classification of gliomas. The new World Health Organization (WHO) 2016 classification integrates the phenotypic and genotyping features for a more robust diagnosis. MATERIALS AND METHODS: Fifty gliomas with oligodendroglial morphology according to the WHO 2007 classification were analyzed for isocitrate dehydrogenase 1 and 2 (IDH1/2) mutations by polymerase chain reaction, 1p/19q status by fluorescent in situ hybridization (FISH), and IDH1 and X-linked alpha-thalassemia retardation (ATRX) expression by immunohistochemistry. Tumors were reclassified into oligodendrogliomas, astrocytomas, and glioblastomas (GBMs) according to the new "integrated" diagnostic approach. RESULTS: 30% of previously diagnosed oligodendrogliomas and almost 90% of oligoastrocytomas were reclassified as astrocytomas. Twenty gliomas showed 1p/19q co-deletion, while 18 gliomas showed polysomy of chromosome 1/19. Polysomy of chromosome 1/19 was significantly associated with astrocytic tumors (P ≤ 0.001). Loss of ATRX expression was seen in 20 of 23 WHO grade II/III astrocytomas and 3 of 7 GBMs. All WHO grade II and III gliomas in our cohort showed IDH1/2 mutations. Moreover, 4 of 7 GBMs showed the wild-type IDH1/2 mutation, and 2 of 3 GBMs which showed IDH1/2 mutations were secondary GBMs. There was no significant difference in progression-free and overall survival between WHO grade II and III gliomas, possibly because all these tumors showed IDH1/2 mutations. In multivariate analysis, only the WHO grade (grade IV versus II and III combined) was significantly associated with increased risk of recurrence and death (P = 0.016 and 0.02). CONCLUSION: The new integrated diagnosis provides a more meaningful classification, removing the considerable subjectivity that existed previously.

Neurological complications in carotid body tumors: a 6-year single-center experience.

OBJECTIVE: Carotid body tumors are considered rare. However, there has been an increase in the number of these tumors managed at our center in recent years. Delayed presentation with large tumors is common. We studied the clinical profile, interventions, and outcomes of these tumors and assessed the factors influencing operative neurological morbidity and recurrence. METHODS: This retrospective study was conducted at the Christian Medical College in Vellore, a tertiary care center in south India. We analyzed the inpatient and outpatient records of patients diagnosed to have carotid body tumors undergoing excision from January 1, 2005 to December 31, 2011. Patients diagnosed to have vagal paragangliomas were excluded. RESULTS: Thirty-four of 48 tumors were excised from 32 patients (11 female, 21 male). Average age at presentation was 38.2 years, and three patients had familial bilateral tumors. All patients presented with a painless neck mass. There were 27 Shamblin group III, six Shamblin group II, and one Shamblin group I tumor. Eleven Shamblin group II/III tumors were associated with transient cranial nerve palsy or paresis (32.3%). Two Shamblin group III tumors were associated with perioperative stroke (5.8%). Preoperative embolization was done in 17 tumors, 12 of which were associated with neurological complications (two stroke, nine nerve palsy, one hemianopia). One patient underwent thrombolysis for a middle cerebral artery thrombus and recovered completely on follow-up, and another with a capsuloganglionic infarct managed conservatively had minimal persistent disability. Three patients had persistent nerve palsy (8.8%). Although complications were more common in patients with higher Shamblin group tumors, the difference was not statistically significant. CONCLUSIONS: The overall rate of neurological complications is higher with tumors of higher Shamblin groups. Preoperative embolization was not effective in reducing neurological complications. The rates of postoperative stroke and permanent cranial nerve palsy after resection of large tumors are acceptable.