Quantitative MRI demonstrates abnormalities of the third ventricle subventricular zone in neurofibromatosis type-1 and sporadic paediatric optic pathway glioma

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MRI provides supporting evidence of third ventricle subventricular involvement in OPG.

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Third ventricle subventricular zone ADC and CBF differs between NF1 and sporadic OPG.

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Third ventricle subventricular zone ADC correlates with vision in sporadic OPG.

Background

The subventricular zone of the third ventricle (TVZ) is a germinal stem cell niche, identified as the possible location of optic pathway glioma (OPG) cell origin. Paediatric OPGs are predominantly diagnosed as low-grade astrocytomas, which are either sporadic or are associated with neurofibromatosis type-1 (NF1). These tumours often cause a significant impairment to visual acuity (VA). Infiltrative/invasive tumour activity is associated with increased apparent diffusion coefficient (ADC) and cerebral blood flow (CBF). This study aimed to determine whether TVZ imaging features differed between sporadic-OPG, NF1-OPG and controls, and whether the ADC and CBF profile at the germinal stem cell niche (the TVZ) correlated with the primary outcome of VA.

Methods

ADC and CBF MRI data were acquired from 30 paediatric OPG patients (median age 6 years; range 8 months–17 years), along with VA measurements, during clinical surveillance of their tumour. Values for mean ADC and maximum CBF were measured at the TVZ, and normalized to normal-appearing grey matter. These values were compared between the two OPG groups and the healthy control subjects, and multivariate linear regression was used to test the linear association between these values and patient’s VA.

Results

In the TVZ, normalized mean ADC was higher in NF1-associated OPG patients (N = 15), compared to both sporadic OPG patients (N = 15; p = 0.010) and healthy controls (N = 14; p < 0.001). In the same region, normalized maximum CBF was higher in sporadic OPG patients compared to both NF1-OPG patients (p = 0.016) and healthy controls (p < 0.001). In sporadic OPG patients only, normalized mean ADC in the TVZ was significantly correlated with visual acuity (R² = 0.41, p = 0.019). No significant correlations were found between TVZ CBF and ADC values and visual acuity in the NF1-associated OPG patients.

Conclusion

Quantitative MRI detects TVZ abnormalities in both sporadic and NF1-OPG patients, and identifies TVZ features that differentiate the two. TVZ features may be useful MRI markers of interest in future predictive studies involving sporadic OPG.

Comparison between surgical fusion and the growing-rod technique for early-onset neurofibromatosis type-1 dystrophic scoliosis

Background

Spinal deformities constitute one of the most common types of manifestations of neurofibromatosis type-1 (NF-1), which can lead to either dystrophic or non-dystrophic early-onset scoliosis (EOS). Surgical treatment for EOS with NF-1 is challenging, and the outcomes have rarely been reported. The anterior-posterior procedure is widely used, but posterior-only fusion is theoretically easier and safer to perform. Is it possible that a new surgery that accommodates growth is a better choice? A direct comparison between posterior fusion and growth-friendly surgery in terms of surgical outcomes has not yet been conducted in dystrophic EOS with NF-1 patients.

Methods

Baseline information was extracted from the NF-1 database at our institute with approval from the local ethics committee. All enrolled patients were diagnosed with NF-1. Clinical and radiographic data were recorded preoperatively, after the initial surgery, and at the final follow-up. Implant-related, alignment, neurological complication and unplanned revision surgery data were recorded. We compared the outcomes of these two groups in terms of curve correction, growth parameters, complications and unplanned revision surgeries.

Results

There were eight patients in the PF group and eight patients in the GR group, with a mean follow-up of 51.0 ± 17.5 months. The main curve size was similar (PF 67.38° ± 17.43° versus GR 75.1° ± 26.43°, P = 0.501), and there were no significant differences in the initial surgery correction rate or the rate of correction. However, the patients in the GR group exhibited more T1-S1 growth during the follow-up overall and per year than did those in the PF group. The operative time was significantly longer for the PF group than for the GR group (PF, 4.39 ± 1.38 vs. GR, 3.00 ± 0.42 h; p = 0.008). Significantly fewer segments were involved in the PF group (8.25 ± 3.20) than in the GR group (13.00 ± 1.60).

Conclusion

For the initial treatment of dystrophic EOS in patients with NF-1, the GR technique is possibly a more appropriate treatment than is the PF technique in terms of trunk growth. However, the repeated procedures required for GR may be a considerable disadvantage. More studies with direct measurement of pulmonary function must be conducted to determine the effect of GR on pulmonary development. More studies with larger sample sizes and longer follow-up periods are needed to fully assess the treatment strategies.

Triple malignancy (NET, GIST and pheochromocytoma) as a first manifestation of neurofibromatosis type-1 in an adult patient

BACKGROUND

Neurofibromatosis type-1 (NF1), also called von Recklinghausen disease, is a rare genetic disease which can lead to the development of benign or even malignant tumors. NF1 is mostly diagnosed in children or early adolescents who present with clinical symptoms. A curative therapy is still missing and the management of NF1 is based on careful surveillance. Concerning tumors which affect the gastrointestinal tract in patients with NF1, the most common is a gastrointestinal stromal tumor (GIST).

CASE PRESENTATION

We present a case of a 58-year-old adult patient with dyspeptic symptoms who was incidentally diagnosed with triple malignancy (pheochromocytoma, multiple GISTs of small intestine and an ampullary NET) as a first manifestation of NF1. The patient underwent surgical treatment (adrenalectomy and pancreaticoduodenectomy) with no complications and after 2 years remains in oncological remission.

CONCLUSION

NF1 is a rare genetic disease which can cause various benign or malignant tumors. The coincidence of GIST and NET is almost pathognomonic for NF1 and should raise a suspicion of this rare disorder in clinical practice.

Ultra-deep amplicon sequencing indicates absence of low-grade mosaicism with normal cells in patients with type-1 NF1 deletions

Different types of large NF1 deletion are distinguishable by breakpoint location and potentially also by the frequency of mosaicism with normal cells lacking the deletion. However, low-grade mosaicism with fewer than 10% normal cells has not yet been excluded for all NF1 deletion types since it is impossible to assess by the standard techniques used to identify such deletions, including MLPA and array analysis. Here, we used ultra-deep amplicon sequencing to investigate the presence of normal cells in the blood of 20 patients with type-1 NF1 deletions lacking mosaicism according to MLPA. The ultra-deep sequencing entailed the screening of 96 amplicons for heterozygous SNVs located within the NF1 deletion region. DNA samples from three previously identified patients with type-2 NF1 deletions and low-grade mosaicism with normal cells as determined by FISH or microsatellite marker analysis were used to validate our methodology. In these type-2 NF1 deletion samples, proportions of 5.3%, 6.6% and 15.0% normal cells, respectively, were detected by ultra-deep amplicon sequencing. However, using this highly sensitive method, none of the 20 patients with type-1 NF1 deletions included in our analysis exhibited low-grade mosaicism with normal cells in blood, thereby supporting the view that the vast majority of type-1 deletions are germline deletions.

Influence of learning disabilities on the tumour predisposition syndrome NF1--survey from adult patients' perspective

AIM

To analyze psychosocial burdens associated with neurofibromatosis type-1 (NF1) phenotype--visible symptoms, medical complications, learning disabilities (LD)--from patients' perspective with focus on LD.

PATIENTS AND METHODS

A survey of 228 adult patients with NF1 was carried-out. Symptoms to estimate disease severity and visibility, and learning disability were assessed. Outcome parameters were social situation and psychosocial aspects.

RESULTS

Social situation and psychosocial aspects differed depending on NF1 phenotype. Patients with LD (n=55) were less frequently in a partnership (p=0.005) or had children (p=0.015) than those without (n=132). They also reported a higher frequency of depression (p=0.019) and sensitivity to stress (p<0.001) and more uncertainty regarding NF1-associated symptoms. These differences were significant when adjusting for disease severity and self-perceived disease visibility.

CONCLUSION

Beside the psychosocial needs of patients with LD with NF1, medical management of this sub-group should include doctor-patient communication in easy language to compensate for patients' lack of knowledge about symptoms associated with cancer.

Behavior of advanced gastrointestinal stromal tumor in a patient with von-Recklinghausen disease: Case report

Gastrointestinal stromal tumors (GISTs) represent a malignant gastrointestinal tumor of neurofibromatosis type 1 (NF1) Von Recklinghausen disease. In the current case, we report a 27-year-old woman with NF1, who presented with a lower abdominal mass, symptomatic anaemia, and significant weight loss. We employed multiple approaches to assess the tumor behavior, including computed tomography (CT) scan, surgical tumor resection, histological and immunohistochemical analysis and gene sequencing. Additionally, the patient was given Imatinib mesylate (Gleevec) as adjuvant therapy. CT scan delineated a large thick wall cavity lesion connecting to the small bowel segment. Resection of the tumor yielded a mass of 17 cm × 13 cm with achievement of safety margins. The diagnosis was GIST, confirmed by immunohistochemical expression of CD117, CD34, and Bcl-2. Sequencing revealed no mutations in either KIT or platelet-derived growth factor receptor-alpha, genes which are mutated in over 85% of sporadic GIST cases. Further, there was no evidence of recurrence, metastasis or metachronous GIST for over three years in our patient. From our analyses, we believe selective genotyping is advisable for high risk patients to predict potential tumor behavior.