Pathology Quiz: Brain and CNS Tumors

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Questions and Answers

What is the typical location of Subependymal giant cell astrocytoma (SEGA)?

Retina

Third ventricle

Subependymal tissue of the cerebral cortex

Lateral ventricles adjacent to the foramen of Monro (correct)

What is a rare acute manifestation of Subependymal giant cell astrocytoma (SEGA)?

Growth of subependymal nodule(s) (SENs)

Massive spontaneous haemorrhage (correct)

Increased intracranial pressure

Obstructive hydrocephalus

What is the ICD-O coding for Subependymal giant cell astrocytoma (SEGA)?

XH1L48

2A00.0Y

9384/1 (correct)

15505165

What is the CNS WHO grade of Subependymal giant cell astrocytoma (SEGA)?

Grade 1 Signup and view all the answers

What is the name of the editor responsible for Subependymal giant cell astrocytoma (SEGA)?

Guido Reifenberger Signup and view all the answers

What is the typical location of SEGAs on CT scans?

In the lateral ventricles, near the foramen of Monro Signup and view all the answers

What is the incidence rate of SEGA among patients with Tuberous Sclerosis?

5-15% Signup and view all the answers

What is the role of mTOR inhibitors in the treatment of SEGA?

They reduce tumour volume Signup and view all the answers

What is the distinguishing feature between SEGA and SEN?

Size, with SEGAs being ≥ 5 mm and SENs being < 5 mm Signup and view all the answers

What is the genetic profile of SEGAs?

SEGAs have a strong association with Tuberous Sclerosis and show evidence of biallelic inactivation of TSC1 or TSC2 Signup and view all the answers

What is the characteristic appearance of SEGAs in terms of their location?

They arise from the wall of the lateral ventricle, close to the foramen of Monro. Signup and view all the answers

What is the average Ki-67 proliferation index in SEGAs?

3% Signup and view all the answers

What is the characteristic histopathological feature of SEGAs?

Circumscribed, moderately cellular tumours with a wide spectrum of glial phenotypes. Signup and view all the answers

What is the frequent immunohistochemical feature of SEGAs?

Uniform and intense immunoreactivity for S100. Signup and view all the answers

What is the rare complication of SEGAs?

Craniospinal dissemination. Signup and view all the answers

What is the primary immunohistochemical feature that helps differentiate SEGA from its morphological mimics?

Nuclear immunoreactivity for TTF1 Signup and view all the answers

What ultrastructural feature may be detectable in SEGA cells?

Microtubules Signup and view all the answers

In which situations may DNA methylome profiling be helpful in establishing the diagnosis of SEGA?

In histologically ambiguous cases Signup and view all the answers

What is associated with optimal outcome in patients with SEGA?

Early detection and treatment Signup and view all the answers

What has been reported to result in significant reduction of tumour size and control of SEGA progression?

Inhibition of mTOR with everolimus Signup and view all the answers

Study Notes

Subependymal Giant Cell Astrocytoma (SEGA)

Definition

A periventricular tumor composed partly of large ganglion-like astrocytes, strongly associated with tuberous sclerosis (TS) (CNS WHO grade 1)

ICD-O and ICD-11 Coding

ICD-O: 9384/1
ICD-11: 2A00.0Y & XH1L48

Localization

Typically arise from the subependymal tissue of the lateral ventricles adjacent to the foramen of Monro
Rare locations include the third ventricle and the retina

Clinical Features

Most patients present with signs and symptoms of increased intracranial pressure
Tumor growth at the foramen of Monro can block cerebrospinal fluid circulation, leading to obstructive hydrocephalus
Massive spontaneous hemorrhage may be an acute manifestation
Growth of subependymal nodule(s) (SENs) into a SEGA is usually a gradual process

Imaging

On CT, SEGAs appear as solid, partially calcified masses located in the walls of the lateral ventricles
On MRI, the tumors are usually heterogeneous, isointense, or slightly hypointense on T1-weighted images, and hyperintense on T2-weighted images, with marked contrast enhancement

Epidemiology

SEGA is the most common CNS neoplasm in patients with TS
Incidence rate of SEGA among patients with TS is 5–15%
Calculated overall incidence of SEGAs in the US Surveillance, Epidemiology, and End Results Program (SEER) 18 database is 0.027 cases per 100 000 person-years

Etiology

SEGA has a strong association with inherited TS
Evidence of biallelic inactivation of the TSC1 or TSC2 gene supports the hypothesis that SEGAs arise as a consequence of a second-hit mechanism

Pathogenesis

Activation of the mTOR pathway has been shown in SEGAs, and clinical trials have shown reductions in tumor volumes using mTOR inhibitors
Cell of origin: SEGAs demonstrate glial, neuronal, and mixed neuroglial features, suggesting a cell of origin with the capacity to undergo differentiation along glial, neuronal, and neuroendocrine lines

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Description

This quiz covers topics related to brain and CNS tumors, including ICD-O and ICD-11 coding, clinical features, epidemiology, etiology, and more.