Thomas Robertson

Posterior fossa and spinal gangliogliomas form two distinct clinicopathologic and molecular subgroups

BackgroundGangliogliomas are low-grade glioneuronal tumors of the central nervous system and the commonest cause of chronic intractable epilepsy. Most gangliogliomas (>70%) arise in the temporal lobe, and infratentorial tumors account for less than 10%. Posterior fossa gangliogliomas can have the features of a classic supratentorial tumor or a pilocytic astrocytoma with focal gangliocytic differentiation, and this observation led to the hypothesis tested in this study - gangliogliomas of the posterior fossa and spinal cord consist of two morphologic types that can be distinguished by specific genetic alterations.ResultsHistological review of 27 pediatric gangliogliomas from the posterior fossa and spinal cord indicated that they could be readily placed into two groups: classic gangliogliomas (group I; n = 16) and tumors that appeared largely as a pilocytic astrocytoma, but with foci of gangliocytic differentiation (group II; n = 11). Detailed radiological review, which was blind to morphologic assignment, identified a triad of features, hemorrhage, midline location, and the presence of cysts or necrosis, that distinguished the two morphological groups with a sensitivity of 91% and specificity of 100%. Molecular genetic analysis revealed BRAF duplication and a KIAA1549-BRAF fusion gene in 82% of group II tumors, but in none of the group I tumors, and a BRAF:p.V600E mutation in 43% of group I tumors, but in none of the group II tumors.ConclusionsOur study provides support for a classification that would divide infratentorial gangliogliomas into two categories, (classic) gangliogliomas and pilocytic astrocytomas with gangliocytic differentiation, which have distinct morphological, radiological, and molecular characteristics.

SMARCB1 (INI-1)-deficient Sinonasal Carcinoma: A Series of 39 Cases Expanding the Morphologic and Clinicopathologic Spectrum of a Recently Described Entity

To more fully characterize the clinical and pathologic spectrum of a recently described tumor entity of the sinonasal tract characterized by loss of nuclear expression of SMARCB1 (INI1), we analyzed 39 SMARCB1-deficient sinonasal carcinomas collected from multiple medical centers. The tumors affected 23 males and 16 females with an age range of 19 to 89 years (median, 52). All patients presented with locally advanced disease (T3, n=5; T4, n=27) involving the sinuses (mainly ethmoid) with variable involvement of the nasal cavity. Thirty patients received surgery and/or radiochemotherapy with curative intent. At last follow-up, 56% of patients died of disease 0 to 102 months after diagnosis (median, 15), 2 were alive with disease, and 1 died of an unrelated cause. Only 9 patients (30%) were alive without disease at last follow-up (range, 11 to 115 mo; median, 26). The original diagnosis of retrospectively identified cases was most often sinonasal undifferentiated carcinoma (n=14) and nonkeratinizing/basaloid squamous cell carcinoma (n=5). Histologically, most tumors displayed either a predominantly basaloid (61%) or plasmacytoid/rhabdoid morphology (36%). The plasmacytoid/rhabdoid form consisted of sheets of tumor cells with abundant, eccentrically placed eosinophilic cytoplasm, whereas similar cells were typically rare and singly distributed in the basaloid variant. Glandular differentiation was seen in a few tumors. None of the cases showed squamous differentiation or surface dysplasia. By immunohistochemistry, the tumors were positive for pancytokeratin (97%), CK5 (64%), p63 (55%), and CK7 (48%); and they were negative for NUT (0%). Epstein-Barr virus and high-risk human papillomavirus was not detected by in situ hybridization. Immunohistochemical loss of SMARCB1 (INI1) expression was confirmed for all 39 tumors. Investigation of other proteins in the SWI/SNF complex revealed co-loss of SMARCA2 in 4 cases, but none were SMARCA4 deficient or ARID1A deficient. Of 27 tumors with SMARCB1 fluorescence in situ hybridization analysis, 14 showed homozygous (biallelic) deletions and 7 showed heterozygous (monoallelic) deletions. SMARCB1-deficient sinonasal carcinoma represents an emerging poorly differentiated/undifferentiated sinonasal carcinoma that (1) cannot be better classified as another specific tumor type, (2) has consistent histopathologic findings (albeit with some variability) with varying proportions of plasmacytoid/rhabdoid cells, and (3) demonstrates an aggressive clinical course. This entity should be considered in any difficult-to-classify sinonasal carcinoma, as correct diagnosis will be mandatory for optimizing therapy and for further delineation of this likely underdiagnosed disease.

Glioma surgical aspirate: a viable source of tumor tissue for experimental research

Brain cancer research has been hampered by a paucity of viable clinical tissue of sufficient quality and quantity for experimental research. This has driven researchers to rely heavily on long term cultured cells which no longer represent the cancers from which they were derived. Resection of brain tumors, particularly at the interface between normal and tumorigenic tissue, can be carried out using an ultrasonic surgical aspirator (CUSA) that deposits liquid (blood and irrigation fluid) and resected tissue into a sterile bottle for disposal. To determine the utility of CUSA-derived glioma tissue for experimental research, we collected 48 CUSA specimen bottles from glioma patients and analyzed both the solid tissue fragments and dissociated tumor cells suspended in the liquid waste fraction. We investigated if these fractions would be useful for analyzing tumor heterogeneity, using IHC and multi-parameter flow cytometry; we also assessed culture generation and orthotopic xenograft potential. Both cell sources proved to be an abundant, highly viable source of live tumor cells for cytometric analysis, animal studies and in-vitro studies. Our findings demonstrate that CUSA tissue represents an abundant viable source to conduct experimental research and to carry out diagnostic analyses by flow cytometry or other molecular diagnostic procedures.

Overview and recent advances in neuropathology. Part 1: Central nervous system tumours

This review highlights the recent changes to the World Health Organization (WHO) 4th edition of the classification of central nervous system tumours. The mixed glial and neuronal tumour group continues to expand to encompass three new subtypes of glioneuronal tumours. The main diagnostic points differentiating these tumours are covered. Also covered is an update on issues relating to grading of astrocytic, oligodendroglial and pineal tumours and the recent molecular subtypes observed in medulloblastomas. The theme of molecular genetics is continued in the following section where the four subtypes in the molecular subclassification of glioblastoma; classical, mesenchymal, proneural and neural are outlined. The genetic profile of these subtypes is highlighted as is their varying biological responses to adjuvant therapies. The relationship between chromosome 1p and 19q deletions and treatment responsive oligodendrogliomas is discussed, as are the newer advances relating to silencing of the MGMT gene in astrocytomas and mutations in the IDH-1 gene in both astrocytomas and oligodendrogliomas. The final section in this article provides an update on the concept of glioma stem cells.

Atypical clinical presentations of the A3243G mutation, usually associated with MELAS

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke‐like episodes (MELAS) is a clinical syndrome associated with mitochondrial abnormalities. In approximately 80% of patients, the syndrome is associated with the A3243G mutation. However, it has been realized that the A3243G mutation is not uncommon in the general population and is found in many patients with clinical presentations other than MELAS. We present four patients who presented with rhabdomyolysis, muscle fatigue, external ophthalmoplegia and myoclonic jerks respectively. These patients were all found to have the A3243G mutation on muscle biopsy. These patients illustrate the variety of presentations associated with A3243G mutation.

Optic atrophy due to Curvularia lunata mucocoele.

The authors report on the case of a 57-year-old male who presented with poor vision of his right eye. He had right optic nerve atrophy secondary to neural compression by a mucocoele in the pituitary fossa. The patient underwent transphenoidal resection of the mucocoele. Microbiology revealed Curvularia lunata and Enterobacter aerogenes present in the specimen. He was treated with liposomal Amphotericin B and meropenem. Assessment of vision post-operatively demonstrated improvement in his visual acuity.On reviewing the published literature, this case was found to be the first in which Curvularia had caused optic neuropathy. There have been only five previously documented reports of Curvularia causing CNS infections [1–6]. This case demonstrates the importance of obtaining a tissue diagnosis together with appropriate surgical and medical management in the treatment of invasive fungal disease.

Multifocal supratentorial diffuse glioma in a young patient with Ollier disease

Ollier disease is a rare disorder characterised by the development of multiple enchondromas in long bones. Here we present a 19-year-old man with Ollier disease who also developed three synchronous brain tumours. Craniotomy, biopsy and debulking was performed for one lesion followed by a period of observation, and 9 months later he underwent a second craniotomy and debulking for symptomatic progression. Histopathological examination revealed a diagnosis of multifocal diffuse glioma (World Health Organization grade II). This report highlights the increased incidence of primary brain tumours in patients with Ollier disease and identifies the importance of screening patients with Ollier disease for primary neoplasms.

Retinal hemorrhages associated with meningitis in a child with a congenital disorder of glycosylation

A 9-month old infant presented in a state of shock to a district hospital. She was subsequently referred to the regional tertiary hospital. On admission, bruises were noted on the vertex of the skull. Retinal hemorrhages were present on ophthalmological examination. CT scan of the brain showed poor grey–white matter differentiation with apparent frontoparietal fractures of the skull. Her case was subsequently referred to the relevant authorities as it was suspicious for nonaccident injury (NAI). Her condition deteriorated and she died the next day. Postmortem examination showed that the bruises on the vertex were caused by rapid widening of the sutures of the skull, caused by rising intracranial pressure. There was no skull fracture or evidence of trauma. Histological examination of the brain showed meningitis which had extended to the optic nerve sheath. Hemorrhages were noted in the retinas as well as the optic nerve sheath. An incidental congenital disorder of glycosylation (CDG) was diagnosed on brain histology and confirmed by metabolic tests. Retinal hemorrhages are known to occur in head injuries especially in association with NAI. In this case, suspicion of NAI was further augmented by the presence of apparent bruises on the head. The full postmortem examination showed no evidence of injuries and instead showed that the child was suffering from meningitis. Blood culture grew Group A Streptococcus pyogenes. The underlying mechanisms for such a presentation and the association with CDG are discussed.

Sebaceous adenoma arising within an ovarian mature cystic teratoma in Muir-Torre syndrome.

This is the first reported case of a sebaceous adenoma arising within an ovarian mature cystic teratoma in a patient with Muir-Torre syndrome. The pathologic findings and a literature review are presented, including the importance and possible benefits of an early diagnosis of Muir-Torre syndrome. It is proposed that the presence of a sebaceous adenoma in an ovarian cystic teratoma may serve as a useful trigger to consider further history and investigations, with the goal of identifying an important genetic cancer predisposition syndrome.

When does ALS start? A novel SOD-1 p.Gly142Arg mutation causing motor neurone disease with prominent premorbid cramps and spasms

Amyotrophic lateral sclerosis (ALS) is characterised by progressive muscle weakness and degeneration of upper and lower motor neurones. The risk of developing ALS is partly genetic and partly environmental. Approximately 10% of cases of ALS are familial and a number of causative genes have been identified.1 Many of the causative genes encode proteins that accumulate in cells in ALS. Mutations of the copper-zinc (Cu, Zn) superoxide dismutase type 1 (SOD1) gene account for approximately 20% of familial and 3% of sporadic ALS cases. Over 150 mutations in the coding region of SOD1 have been found in patients with ALS worldwide, with variation of the frequency of SOD1 mutations in different populations. However, not all SOD1 mutations are pathogenic and there is a variety of clinical presentations of patients with pathogenic mutations. Furthermore, the different mutations have diverse effects on the structure of the SOD1 protein, and some cause no abnormality other than decreasing the net charge of the protein. We now describe two sisters, from a family of Caucasian genetic background, with a novel SOD1 mutation, and unusual clinical features before the onset of weakness. The proband developed painful leg and hand cramps and leg stiffening in her sixth decade. After about 10 years, she …