Diagnosis and localisation of insulinoma: the value of modern magnetic resonance imaging in conjunction with calcium stimulation catheterisation

CONTEXT

Preoperative localisation of insulinoma improves cure rate and reduces complications, but may be challenging.

OBJECTIVE

To review diagnostic features and localisation accuracy for insulinomas.

DESIGN

Cross-sectional, retrospective analysis.

SETTING

A single tertiary referral centre.

PATIENTS

Patients with insulinoma in the years 1990-2009, including sporadic tumours and those in patients with multiple endocrine neoplasia syndromes.

INTERVENTIONS

Patients were identified from a database, and case notes and investigation results were reviewed. Tumour localisation by computed tomography (CT), magnetic resonance imaging (MRI), octreotide scanning, endoscopic ultrasound (EUS) and calcium stimulation was evaluated.

MAIN OUTCOME MEASURE(S)

Insulinoma localisation was compared to histologically confirmed location following surgical excision.

RESULTS

Thirty-seven instances of biochemically and/or histologically proven insulinoma were identified in 36 patients, of which seven were managed medically. Of the 30 treated surgically, 25 had CT (83.3%) and 28 had MRI (90.3%), with successful localisation in 16 (64%) by CT and 21 (75%) by MRI respectively. Considered together, such imaging correctly localised 80% of lesions. Radiolabelled octreotide scanning was positive in 10 out of 20 cases (50%); EUS correctly identified 17 lesions in 26 patients (65.4%). Twenty-seven patients had calcium stimulation testing, of which 6 (22%) did not localise, 17 (63%) were correctly localised, and 4 (15%) gave discordant or confusing results.

CONCLUSIONS

Preoperative localisation of insulinomas remains challenging. A pragmatic combination of CT and especially MRI predicts tumour localisation with high accuracy. Radionuclide imaging and EUS were less helpful but may be valuable in selected cases. Calcium stimulation currently remains useful in providing an additional functional perspective.

Preservation of basophils in dapsone-induced agranulocytosis suggests a possible pathogenetic role for leucocyte peroxidases

We describe a hitherto unreported laboratory observation, namely the selective preservation of basophils, in a case of severe dapsone-induced agranulocytosis. Dapsone is known to be metabolised by peroxidases to nitroso derivatives in non-hemopoietic cells where these can in turn act as haptens. Our observation that basophils are selectively spared in this syndrome supports the hypothesis that leucocyte peroxidases function in a similar way to facilitate the pathogenesis of this form of agranulocytosis in susceptible individuals.

High rate of unprovoked recurrent venous thrombosis is associated with high thrombin-generating potential in a prospective cohort study

OBJECTIVE

To determine the predictive value of measurement of parameters of thrombin generation for unprovoked recurrent venous thrombosis.

METHODS

Measurements were made of thrombin generation in a prospective cohort study of 188 patients with a first episode of venous thrombosis that was unprovoked, or provoked by a non-surgical trigger.

RESULTS

The endogenous thrombin potential (ETP) was the only parameter associated with unprovoked recurrent thrombosis in a multivariate model [hazard ratio (HR) 1.3 per 100 nmol L min(-1) increase, 95% confidence interval (CI) 1.0-1.6]. Patients with a high ETP had a significantly higher rate of unprovoked recurrence than those with a low ETP (HR 2.9, 95% CI 1.3-6.6, cumulative recurrence at 4 years 27% vs. 11%). Patients with an unprovoked first event had a significantly higher rate of unprovoked recurrence than those with a provoking factor (HR 2.7, 95% CI 1.2-6.1), and in these patients there was a significantly higher rate of unprovoked recurrence in association with a high ETP (HR 4.0, 95% CI 1.3-11.8). After adjustment for D-dimer, thrombophilia, sex, and whether or not the first event was unprovoked, a high ETP remained a significant predictor of recurrence (HR 2.6, 95% CI 1.2-6.0).

CONCLUSIONS

This study demonstrates a high rate of unprovoked recurrent venous thrombosis in patients presenting with a first episode of venous thrombosis and a high ETP.

Durally-based occipital cavernous haemangioma indistinguishable from meningioma

A rare case of a durally-based cavernous haemangioma over the occipital convexity is presented. The lesion had been preoperatively diagnosed as a meningioma. The clinical, radiological and pathological features of the case are described, along with a review of the relevant literature.

Repair under cardiopulmonary bypass of giant internal carotid aneurysm following GDC embolization

Endovascular embolization techniques have increased the complexity of aneurysm surgery in those lesions that have been incompletely obliterated. We report a case of giant cerebral aneurysm initially treated with Guglielmi detachable coils which required cardiopulmonary bypass for successful endoaneurysmorrhaphy.

Failed stereotactic radiosurgery for acoustic neuroma

A case of recurrent acoustic neuroma in a 58-year-old man is presented. The tumour was initially subtotally removed and then was irradiated using stereotactic radiosurgery. He represented with ataxia and new onset headache four years later and underwent further surgery for recurrence of his acoustic neuroma. The literature is reviewed and the authors' view point on the different modalities of treatment is discussed.

Anterior clinoid mucocele causing acute monocular blindness

We report a patient who presented with acute painful monocular visual loss reminiscent of idiopathic optic neuritis. After treatment with corticosteroids was commenced, an anterior clinoid mucocele causing compressive optic neuropathy was demonstrated on imaging studies. The diagnosis was proven histopathologically following excision of the lesion via craniotomy. Although very rare as a cause of optic neuropathy, anterior clinoid mucocele should be excluded by adequately imaging the optic canal, as visual prognosis is poor if surgical decompression is not performed in a timely fashion.

Desmoplastic infantile ganglioglioma/astrocytoma with cerebrospinal metastasis

Desmoplastic infantile ganglioglioma and astrocytoma (DIG/DIA) are rare intracranial tumours of early childhood that involve superficial cerebral cortex and leptomeninges. Despite the large size of the tumour and the presence of poorly differentiated cells, it is believed that the prognosis of DIG/DIA is excellent. We report two patients with DIG/DIA who developed multiple cerebrospinal metastases. To our knowledge only two similar cases have been reported in the literature. It appears that not all tumours with histological features of DIG/DIA behave in a benign way. It is possible that what is called DIG/DIA may be a heterogenous group of tumours with variable biological behaviour.

The diagnosis and differential diagnosis of endogenous Cushing's syndrome

Cushing's syndrome (CS) is a physically and psychologically disabling disease associated with high morbidity resulting from inappropriate elevation of circulating free cortisol levels. The main features of CS are disturbance of the normal circadian rhythm of cortisol secretion, impairment of the normal feedback of the hypothalamo-pituitary-adrenal (HPA)-axis, and excessive integrated 24 hours cortisol secretion. All biochemical tests used for the diagnosis of CS rely upon the ascertainment of a disturbance of these features. However, the diagnosis of CS (endogenous hypercortisolism) still remains a challenge, although the evolution of several diagnostic tests has allowed diagnosis at an earlier stage. In the initial investigation of CS, tests of high sensitivity are required to identify patients at risk, which are followed by tests of high specificity to confirm the diagnosis and establish the precise aetiology. This review will discuss the various causes of endogenous CS and focus on established and evolving diagnostic procedures used for its diagnosis, as several studies with large number of patients have recently appeared in the literature validating current practice and proposing improved diagnostic algorithms.

Arthroscopic subacromial decompression performed under local anesthesia

Shoulder arthroscopy is usually performed under general anesthesia or interscalene block. General anesthesia may be contraindicated and interscalene block sometimes fails. We had 8 patients who were at high-risk and, therefore, shoulder arthroscopy and decompression were performed under local anesthesia in the beach-chair position. We used 50 mL of 1% lidocaine; 30 mL were infiltrated into the skin and underlying tissues and into the glenohumeral joint, and the rest was infiltrated into the subacromial joint. Before the infiltration, all patients were given 5 mg midazolam and 0.1 mg fentanyl intravenously. All 8 patients were satisfied with the analgesia provided by the anesthesia. We conclude that arthroscopy and subacromial decompression can be readily performed under local anesthesia in combination with efficient sedation.

Long term outcome in children with Moyamoya disease: experience with 16 patients

We present our experience with 16 children with Moyamoya disease/variant diagnosed at the Royal Alexandra Hospital for Children, Westmead, Sydney, Australia in the period between January 1982 and March 2004. Thirteen of these patients had one of the different revascularisation procedures. We reviewed the modes of presentation and the long-term outcome in these children. In our series the functional outcome was related to the functional status at presentation and was not related to the type of surgical procedure or age at presentation. We believe this is the largest reported series of Moyamoya disease/variant in Australia.

[The treatment of meniscal tear with bio-absorbable arrow--3 years follow-up]

BACKGROUND

The introduction of bio-absorbable materials has improved the ability to offer a simple fast and friendly solution to meniscal tears. The technique of meniscal suture with bio-absorbable arrows is associated with lower morbidity and complication rates.

AIM

The clinical evaluation of treatment of meniscal tear by suture with bio-absorbable arrows.

METHODS

During the period 1997-2004, 14 patients underwent arthroscopic all-inside meniscus repair. The "Biofix" bio-absorbable arrows fixation technique was used. Fourteen patients were followed--11 males and 3 females. Their mean age was 23 years (range 16-34 years). Follow-up period was an average of 34 months (range 6-72 months). Sport injuries were the main cause of meniscal tear (60%). Other causes included: work accidents (20%) and military accidents (20%). All the tears were located in an area suitable for suture in the "red-red" or "red-white" zone.

RESULTS

One patient had a tear of the lateral meniscus. Four patients had anterior cruciate ligament (ACL) tear. The mean length of the tear was 9.6 mm. Tears were fixed with 2.5 arrows in average. The clinical evaluation was by the Lysholm Score. Excellent results were reported in 10 patients, good in one patient, fair in 2 patients and poor in 1 patient. One patient suffered from a transient tender point on the medial joint line due to protruded arrow tip, one patient needed a menisectomy due to unresolved symptoms and one patient underwent ACL reconstruction.

CONCLUSION

Meniscal suture with bio-absorbable arrows is an easy and reliable suture technique compared to the classical methods and it seems to have a lower complication rate. Further studies are needed to establish the quality of the repair and the associated morbidity.

A rapid method for analyzing serum pro-insulin-like growth factor-II in patients with non-islet cell tumor hypoglycemia

CONTEXT

Non-islet cell tumor hypoglycemia (NICTH) results from the hypersecretion of pro-IGF-II by a large, usually mesenchymal tumor. Detection of pro-IGF-II in serum is a potential tumor marker in these patients.

OBJECTIVE

The aim of this study was to validate a rapid and reliable method for determining serum pro-IGF-II.

PATIENTS

Serum samples from 16 patients with NICTH were studied.

MAIN OUTCOME MEASURE

The main outcome measure was serum concentration of pro-IGF-II determined by immunoblot analysis of pro-IGF-II and mature IGF-II after 16.5% tricine-SDS-PAGE, which was compared with pro-IGF-II measured by standard RIA after size-exclusion acid chromatography.

RESULTS

The analyses of patients' sera by size-exclusion acid chromatography showed that 68 +/- 19% of IGF-II were present in the pro-IGF-II form, whereas only 18 +/- 4% corresponded to pro-IGF-II in controls. Scanning densitometry of immunoblots showed 67 +/- 16% in the bands corresponding to pro-IGF-II in patients' sera, compared with 27 +/- 9% in controls. The detection sensitivity of tricine-SDS-PAGE method was the same as for size-exclusion chromatography, but the tricine-SDS-PAGE method is quicker and requires smaller amounts of serum.

CONCLUSION

Tricine-SDS-PAGE followed by IGF-II immunoblot analysis provides a rapid, reproducible, and sensitive method for the separation of serum pro-IGF-II from mature IGF-II and is a useful laboratory evaluation of patients with a clinical diagnosis of NICTH.

Cerebellar liponeurocytoma

A case of cerebellar liponeurocytoma in a 34-year-old man is reported. There are only 19 other cases reporting this entity in the medical literature. The diagnostic, radiological and clinical features associated with this tumour are reviewed and discussed in relation to our case. The differences in behaviour and prognosis between medulloblastoma and cerebellar liponeurocytoma are presented with the corresponding implications for management.

Extradural hematoma causing venous sinus obstruction and pseudotumor cerebri syndrome

CASE REPORT

The case of a small right occipital extradural hematoma in a 10-year-old girl is presented. The patient had bifrontal occipital headache out of proportion to the size of the hematoma, as well as diplopia. MR venography revealed compression and occlusion of the dominant right transverse sinus resulting in a pseudotumor cerebri syndrome.

DISCUSSION

The relationship between venous sinus obstruction and the pseudotumor syndrome is discussed. Clinicians should be aware of the possible effects of an extra-axial collection on the cerebral venous sinuses.

Outcome scoring in neurosurgery: the cognitive outcome score, an alternative to the Glasgow outcome scale

The qualitative method, the Glasgow outcome scale, remains the convention for patient outcome assessment in the neurosurgical literature. This is despite the fact that sampling methods subject to bias confer low confidence in the conclusions. An alternative, quantitative method, the cognitive outcome score (COS), decreases bias, is cost effective and delivered in less than 10 min. Utilisation of the COS in statistical correlations against common clinical parameters is discussed in theory and practice.

Metabolites from cerebrospinal fluid in aneurysmal subarachnoid haemorrhage correlate with vasospasm and clinical outcome: a pattern-recognition 1H NMR study

Following subarachnoid haemorrhage the most significant complication is sustained cerebral vascular contraction (vasospasm), which may result in terminal brain damage from cerebral infarction. Despite this, the biochemical cause of vasospasm remains poorly understood. In this study, the global high-concentration metabolite composition of CSF has been correlated with patient outcome after subarachnoid haemorrhage using multivariate statistics and 1H NMR spectroscopy. In total, 16 patients with aneurysmal subarachnoid haemorrhage (aSAH) were compared with 16 control patients who required a procedure where CSF was obtained but did not have aSAH. Multivariate statistics readily distinguished the aSAH group from the heterogeneous control group, even when only those controls with blood contamination in the CSF were used. Using principal components analysis and orthogonal signal correction, vasospasm was correlated to the concentrations of lactate, glucose and glutamine. These pattern recognition models of the NMR data also predicted Glasgow Coma Score (54% within +/- 1 of the actual score on a scale of 1-15 for the whole patient group), Hunt and Hess SAH severity score (88% within +/- 1 of the actual score on a scale of 1-5 for the aSAH group) and cognitive outcome scores (78% within +/- 3 of the actual score on a 100% scale for the whole patient group). Thus, the approach allowed the prediction of outcome as well as confirming the presence of aSAH.

Cranial venous outflow obstruction and pseudotumor Cerebri syndrome

The pathophysiology of PTS including idiopathic intracranial hypertension or 'BIH', remains controversial. The older literature frequently referred to pathology in the cerebral venous drainage but more modern imaging techniques (CT and early MR) failed to reveal gross venous pathology. The role of impaired cranial venous outflow has recently been re-examined in the light of new methods of investigation (advanced MR venography and direct microcatheter venography with manometry) and of treatment (venous sinus stenting). Venous sinus obstruction in PTS is a more common factor in the pathogenesis of the condition than previously recognised. Venous obstruction may be primary, that is, it is the underlying aetiological factor in PTS. Venous sinus obstruction may also be secondary to raised CSF pressure which may exacerbate problems with intracranial compliance and raised CSF pressure. Early experience with venous stenting suggests that it may be a helpful treatment for patients with PTS but more experience and longer follow-up is required to define the subgroups of patients for whom it is most appropriate.

Syringomyelia with Chiari malformation; 3 unusual cases with implications for pathogenesis

Syringomyelia is an important cause of neurological deficit. Most cases of non-traumatic syringomyelia occur in association with a Chiari malformation. We present three unusual examples of syringomyelia with such an association. The first case is that of syringomyelia in a young woman with Marfan's syndrome, a spontaneous CSF leak and intractable intracranial hypotension. The second is a woman with long-standing lumbo-peritoneal shunt for pseudotumour cerebri who developed an acquired Chiari malformation. A young woman with a Dandy-Walker cyst that herniated into the upper cervical canal is the third case. These cases provide a basis for discussion of the pathogenesis and management of syringomyelia and the Chiari malformation in such cases.

Traumatic unilateral deep cerebral venous infarction

A case of unilateral deep cerebral venous infarction in a young man associated with mild head injury is presented. The diagnosis is made on the basis of the clinical, radiological, operative and histopathological findings. We propose that a thrombosis or obstruction of the anterior segment of the basal vein of Rosenthal (BVR) was the primary pathology. This is discussed in respect to current knowledge of deep cerebral venous anatomy and embryology.