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2018 NPB-15

This case was originally published in 2018. The information provided in this case was accurate and correct at the time of initial program release. Any changes in terminology since the time of initial publication may not be reflected in this case.

Clinical History

A 14-year-old girl presented to clinic with a history of concussion three months prior. She reported persistent headaches with exercise during a return visit. MRI demonstrated a left frontal lobe lesion with cystic and solid nodular enhancing components.

Tissue Site
Left frontal lobe

Whole Slide Image

The whole slide image provided is an H&E stained slide of the left frontal lobe from a craniotomy.

Questions

  1. What is the BEST diagnosis?

    1. Dysembryoplastic neuroepithelial tumor

    2. Glioblastoma

    3. Meningoangiomatosis

    4. Oligodendroglioma

    5. Papillary glioneuronal tumor

  2. Which of the following is characteristic for this lesion?

    1. Mucin-filled nodules of oligodendroglial-like cells at the gray/white junction

    2. Perineuronal satellitosis and abundant intercellular mucin

    3. Perivascular radial orientation of tumor cells and abundant intercellular mucin

    4. Rosettes displaying a strong, central immunoreactivity for synaptophysin

    5. Tumor cells exhibiting endodermal, ectodermal, and mesodermal histologies

  3. Which of the following characterizes oligodendroglioma?

    1. 1p/19q codeletions

    2. EGFRvIII mutations

    3. KIAA:BRAF truncations

    4. MYC amplifications

    5. RELA truncations

View Answer Key

Discussion and Diagnosis

The lesion is a dysembryoplastic neuroepithelial tumor (DNT), an uncommon glioneuronal neoplasm about which little is known. Although considered quasi-hamartomatous, DNTs do recur with rare examples found to metastasize. The tumor frequently occurs in a temporal lobe location (but can be found in other regions of the brain) and is often associated with cortical migrational abnormalities resulting in epilepsy, most notably partial complex seizures. DNTs vary in size from 0.5 to 15 mm and occur either in the gray matter or gray/white junction.

Radiographically, the tumor is frequently encountered in the background of an expanded cerebral cortical ribbon. These tumors are typically well-demarcated and T1-hypointense with focal hyperintensity on T2-weighted and fluid attenuated (FLAIR) images, demonstrating a nodular internal structure (Image A and Image B).

Image A: T1 post-gadolinium MRI, coronal.

Image A: T1 post-gadolinium MRI, coronal.

Image B: T1 post-gadolinium MRI, axial.

Image B: T1 post-gadolinium MRI, axial.

The characteristic growth pattern is that of multilobular lesions populated by round, oligodendroglial-like cells embedded in mucin (Image C). The oligodendroglial-like cells are variably distributed in the lobules but commonly are found along thread-like, eosinophilic processes (Image D) apparently emanating from large neurons that float in the mucin (Image E). The significance of this pattern appears to represent a form of “secondary structure” (as originally defined by Scherer) in which the oligodendroglial-like cells are closely aligned to axons but not the neuronal cell bodies. This finding has been called a “specific glioneuronal element” and is helpful in confirming the diagnosis of DNT. A spectrum of cells and histologic morphologies may also be encountered, including pilocytic astrocytes, fibrillar astrocytes, sheets of oligodendroglia, eosinophilic granular bodies, and microcalcifications. Mitotic activity can, in some cases, be quite brisk and associated with an elevated MIB1 labeling index, features not known to be associated with clinical malignancy. At present, there are no specific molecular biomarkers recommended to help identify DNTs; however, the presence of 1p/19q codeletion would definitively rule out the diagnosis. BRAF mutations have been found in a subset of DNTs. The oligodendroglial-like cells exhibit reactivity for S100 protein and are negative for synaptophysin (Image F), NeuN, and neurofilament peptides, denying a mature neuronal phenotype. The chief differential diagnostic consideration is oligodendroglioma, which exhibits the IDH mutation and 1p/19q codeletion. The tumor may occur in other locations, including the cerebellum where it must be distinguished from the rosette-forming glioneuronal tumor, a tumor that, in contrast to DNT, exhibits synaptophysin-positive cores within rosettes and negative S100 reactivity.

Image C: H&E stain.

Image C: H&E stain.

Image D: H&E stain.

Image D: H&E stain.

Image E: H&E stain.

Image E: H&E stain.

Image F: Synaptophysin, IHC stain.

Image F: Synaptophysin, IHC stain.

Dysembryoplastic neuroepithelial tumor, WHO grade I

Take Home Points

  • DNTs are commonly associated with intractable partial complex seizures.
  • DNTs frequently arise in the temporal lobes and are found in association with cortical migrational abnormalities.
  • Synaptophysin staining can be useful in distinguishing the negative DNT lobules from the surrounding positive gray matter.
  • The differential diagnosis of these neoplasms includes oligodendroglioma and rosette-forming glioneuronal tumors.

References

  1. Baisden BL, Brat DJ, Melhem ER, et al. Dysembryoplastic neuroepithelial tumor-like neoplasm of the septum pellucidum: a lesion often misdiagnosed as glioma: report of 10 cases. Am J Surg Pathol. 2001;25(4):494-99.
  2. Chen SY, Wang W, Wang LM, et al. Glioneuronal tumours with features of rosette-forming glioneuronal tumours of the fourth ventricle and dysembryoplastic neuroepithelial tumours: a report of three cases. Histopathology. 2016;68(3):378-87.
  3. Daumas-Duport C. Dysembryoplastic neuroepithelial tumours. Brain Pathol. 1993;3(3):283-95.
  4. Gottschalk J, Korves M, Skotzek-Konrad B, et al. Dysembryoplastic neuroepithelial micro-tumor in a 75-year-old patient with long-standing epilepsy. Clin Neuropathol. 1993;12(3):175-78.
  5. Tomita T, Volk JM, Shen W, et al. Glioneuronal tumors of cerebral hemisphere in children: correlation of surgical resection with seizure outcomes and tumor recurrences. Childs Nerv Syst. 2016;32(10):1839-48.

Answer Key

  1. What is the BEST diagnosis?
    A. Dysembryoplastic neuroepithelial tumor
    B. Glioblastoma
    C. Meningoangiomatosis
    D. Oligodendroglioma
    E. Papillary glioneuronal tumor
  2. Which of the following is characteristic for this lesion?
    A. Mucin-filled nodules of oligodendroglial-like cells at the gray/white junction
    B. Perineuronal satellitosis and abundant intercellular mucin
    C. Perivascular radial orientation of tumor cells and abundant intercellular mucin
    D. Rosettes displaying a strong, central immunoreactivity for synaptophysin
    E. Tumor cells exhibiting endodermal, ectodermal, and mesodermal histologies
  3. Which of the following characterizes oligodendroglioma?
    A. 1p/19q codeletions
    B. EGFRvIII mutations
    C. KIAA:BRAF truncations
    D. MYC amplifications
    E. RELA truncations
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