Amyloid stroma in meningiomas

Incidental 18F-Florapronol Uptake in Meningioma

ABSTRACT

A 76-year-old woman underwent 18F-florapronol (18F-FC119S, an amyloid β imaging PET agent) PET, owing to cognitive impairment. 18F-florapronol PET images revealed an incidental 18F-florapronol uptake in the right frontal lobe. A well-enhancing extra-axial mass in the right frontal lobe was observed on MRI scans, suggesting a meningioma. After excision of the tumor, the biopsy results confirmed it as a meningothelial meningioma.

Pittsburgh Compound-B Uptake in Meningioma With Histopathologic Correlation

Previous studies have reported increased Pittsburgh compound-B (PiB) uptake in meningiomas; however, histological correlation to elucidate the underlying mechanism has not yet been done. We report a case of an 82-year-old woman with an incidental intracranial tumor that showed focal increased PiB uptake. Because of tumor growth, surgical resection was performed, yielding a histological diagnosis of meningioma. Any special and immunochemical staining for amyloid did not reveal amyloid deposition in the tumor. Our findings suggest that increased PiB uptake was not associated with amyloid in this instance.

Pittsburgh compound B (PiB) PET imaging of meningioma and other intracranial tumors

Meningiomas are the most common intracranial tumors. Diagnosis by MRI is generally straightforward, but lack of imaging specificity can present a diagnostic dilemma, particularly in patients with cancer. We report our experience with meningioma identification on Pittsburgh compound B (PiB) PET/CT. Patients who underwent PiB PET/CT from 2006 to 2015 were reviewed to identify those with intracranial tumors. Tumor types were classified by MR appearance, or by pathology when available. Maximum standardized uptake value (SUVmax) measurements of tumor PiB activity were compared across tumor types. 2472 patients underwent PiB PET/CT in the period of interest; 45 patients (1.8%) had probable or definite intracranial tumor. Tumor types were meningioma (29/45, 64%), vestibular schwannoma (7/45, 16%), pituitary macroadenoma (4/45, 9%), metastatic disease (2/45, 4%), and others (3/45, 7%). In patients with meningioma, the mean lesion SUVmax was 2.05 (SD 1.37), versus 1.00 (SD 0.42) in patients with non-meningioma tumors (p < 0.01). A receiver operating curve was created for lesion:cerebellum SUVmax ratio, with an area under the curve of 0.91 for a value of 1.68. At or above this ratio, specificity for meningioma was 100% (95% CI 79–100%) and sensitivity was 76% (95% CI 57–90%). PiB PET activity within an intracranial tumor is a highly specific and reasonably sensitive marker of meningioma. Further prospective evaluation is warranted to validate this result as well as to assess the performance of commercially available beta-amyloid radiotracers in meningioma identification.

Amyloid PET imaging: applications beyond Alzheimer's disease

As a biomarker of beta-amyloid, positron emission tomography (PET) amyloid imaging offers a unique opportunity to detect the presence of this protein in the human body during life. Besides Alzheimer's disease (AD), deposits of beta-amyloid in the brain are also present in other neurodegenerative diseases associated to dementia, such as Parkinson's disease and dementia with Lewy bodies, as well as in other processes affecting brain function, such as cerebral amyloid angiopathy, brain trauma, Down's syndrome and meningiomas, as shown by post-mortem pathology studies. Furthermore, in systemic amyloidosis other organs besides the brain are affected, and amyloid PET imaging may be suitable for the identification of these extra-cerebral amyloid depositions. Finally, the potential use of amyloid PET tracer accumulation in cerebral white matter (WM) as a marker of myelin is being investigated, leading to some promising results in patients with WM lesions and multiple sclerosis. In this article, a review of the ongoing research pointing to a broader application of amyloid PET imaging in clinical practice beyond AD is provided.

Sphenoid wing meningioma behavior on 11C-PiB and 18F-FDG PET

Two patients with mild cognitive impairment underwent C-PiB and F-FDG brain PET. Both patients had previously gone through a contrast-enhanced MRI scan that revealed extra-axial tumors next to the sphenoid wing, suggestive of meningiomas. C-PiB PET images showed a highly increased uptake by the extra-axial masses. These 2 cases represent 1.2% of our C-PiB population (n = 163). No meningioma was found with negative C-PiB uptake. The F-FDG concentration was not increased within the lesions. C-PiB could be used as a meningioma marker.

Unexpected finding of cerebral meningioma on (11)C-PiB PET

A 69-year-old man with no history of neurologic or psychiatric disorders underwent C-PiB PET as a healthy volunteer for amyloid imaging study. C-PiB PET images demonstrated an unexpected increased PiB binding in the left frontal region. MR images demonstrated an extra-axial left frontal mass lesion with mild enhancement, highly suggestive of meningioma. There is a limited amount of published information on the detection of meningioma with C-PiB PET.

Immunohistochemical and morphometric analysis of immunoglobulin light-chain immunoreactive amyloid in psammoma bodies of the human choroid plexus

The aim of this research was to establish the presence of amyloid and to quantify immunohistochemical reactions of kappa and lambda light chains of psammoma bodies of the choroid plexus. Choroid plexus tissue obtained from 14 right lateral ventricles postmortem was processed histologically and stained with Congo red, thioflavin T, and monoclonal antibodies for kappa and lambda light chains. Morphological analysis was performed with a light microscope at lens magnifications of 4×, 10×, 20×, 25×, and 40×. The morphometric characteristics of psammoma bodies that were kappa and lambda positive and negative were analyzed with ImageJ. Histological analysis showed that the psammoma bodies, stromal blood vessel walls, and some epithelial cells reacted positively with Congo red and thioflavin T. Psammoma bodies were predominantly positive for lambda light chains. Lambda positivity was detected inside some stromal blood vessels, which pointed to a probable systemic origin for these light chains. Morphometric analysis showed that the mean optical densities of lambda- and kappa-positive psammoma bodies were significantly higher than those that gave a negative reaction. The percentage of lambda-positive psammoma bodies was significantly higher than the percentage of lambda-negative psammoma bodies in 80% of the cases, while the reaction with kappa light chains was negative in the majority of the cases. Linear regression analysis showed a significant increase in the percentage of lambda-positive psammoma bodies and their mean optical density with age. Finally, it can be concluded that the positive reaction of psammoma bodies in the choroid plexus with respect to amyloid and lambda light chains may point to the presence of light-chain amyloid in their structures.

Incidental finding of meningioma on C11-PIB PET

As a healthy volunteer for amyloid imaging study, a 83-year-old woman with no history of neurologic or psychiatric illness underwent carbon 11-labeled Pittsburgh compound-B (PIB) PET, which showed focal increased PIB binding in the right anterior temporal region. This focal PIB uptake turned out to be a mass lesion on MRI, which was consistent with a benign meningioma. This is the first case report on the incidentally found intracranial meningioma by PIB PET scan, highlighting the excellent sensitivity of PIB radiotracer in detecting brain amyloid deposition.

Psammomatous choroid plexus papilloma

BACKGROUND

Intravertricular papillary neoplasms are derived from choroid plexus epithelium. Although choroid plexus tumors account for 0.4% to 0.6% of all brain tumors, they represent 2% to 4%. Approximately 80% of choroid plexus carcinomas arise in children.

CASES DESCRIPTION

We describe 3 cases of choroid plexus papilloma (CPP) with profuse psammomatous bodies and calcifications that have lost their normal papillary architecture. Immunohistochemistry was positive for glial fibrillary acidic protein in 2 cases, and proliferating cellular nuclear antigen index was higher compared with regular CPPs. All 3 patients were female and were 12, 40, and 48 years old, respectively.

CONCLUSION

We describe psammomatous CPPs and suggest a difference from CPPs because of the more aggressive clinical course, and higher nuclear proliferation index (proliferating cellular nuclear antigen) than the CPPs that lack psammoma bodies.

Microcalcifications in ductal carcinoma in situ of the breast: histochemical and immunohistochemical study

Thirty cases of ductal carcinoma in situ (DCIS) of the breast, showing histological microcalcifications, were studied to clarify their mechanism of formation. Undecalcified sections revealed three types of calcium precipitates: type I and II granular calcifications (GCs) and laminar calcifications (LCs). In type I GCs the core on which the calcium had deposited was constituted mainly by nuclear debris. Type II GCs were predominantly composed by mucosubstances. LCs were the result of calcium deposits on mucoid or proteinaceous material, arranged in concentric lamellae. LCs and type II GCs were mainly present in well and intermediately differentiated DCIS. Type I GCs were observed in only DCIS with necrosis, frequently being present in intermediately and poorly differentiated DCIS.