Background Documentation Central Nervous System • CNS 4.0.0.0
I. Primary Tumor Site, Laterality, and Focality
Since the anatomic site of a neoplasm may correlate with tumor type and prognosis, it should be recorded, if
known.
● For skull location, specify bone involved, such as frontal, parietal, temporal, occipital, etc, if known. The
College of American Pathologists (CAP) cancer protocol for bone should be used for primary tumors of
bone.
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● For dural location, indicate cerebral convexity/lobe, falx, tentorium, posterior fossa, sphenoid wing, skull
base, spinal, or other, if known.
● For leptomeningeal location, indicate cerebral convexity/lobe, posterior fossa, spinal, or other, if known.
● For cerebral lobe location, indicate frontal, temporal, parietal, or occipital lobe, if known. For a deep gray
matter location, indicate basal ganglia, thalamus, or hypothalamus.
● For an intraventricular location, indicate lateral, third, fourth, or cerebral aqueduct, if known.
● For a brain stem location, indicate midbrain, pons, or medulla, if known.
● For spine (vertebral bone), spinal cord, spinal root or spinal ganglion, indicate level (eg, C5, T2, L3), if
known. The CAP cancer protocol for bone should be used for primary tumors of bone.
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The laterality of a neoplasm should be indicated as involving the left or right side of the CNS structure. In some
instances, such as tumors arising in the pineal, pituitary, third ventricular, and other locations, the tumor will be
situated in the midline. A tumor would be considered bilateral if it involved both sides of the brain, such as
glioblastoma extending through the corpus callosum to involve the left and right hemispheres. The focality of a
lesion should be indicated, if possible. Multifocality implies that multiple, noncontiguous lesions are noted on
neuroimaging, such as might be seen in primary CNS lymphoma. A solitary lesion would be considered unifocal.
Margins
Resection margins provide no prognostic information and generally are not required for most CNS neoplasms.
References
1. Laurini JA, Antonescu CR, Cooper K, et al. Protocol for the examination of specimens from patients with
tumors of bone. 2017. Available at www.cap.org/cancerprotocols.
J. Preoperative Treatment and Treatment Effect
Knowledge of preoperative treatment, including radiation therapy, chemotherapy, corticosteroid therapy,
embolization, and other therapy, is helpful for specimen interpretation.
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In particular, prior radiation therapy or
radiosurgery may alter the interpretation of specimens in which there are increased cellular atypia, decreased
proliferative activity, or large areas of radiation-induced change (e.g., coagulative [nonpalisading] necrosis,
vascular hyalinization, and gliosis). The addition of chemotherapy to radiation may further alter histomorphological
appearance. For patients with malignant gliomas, the presence and degree of radiation necrosis appear to be of
prognostic significance. Tumors that show evidence of radiation necrosis are associated with a longer survival,
and the degree of necrosis appears to be prognostically significant.
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Corticosteroid treatment can alter the
pathologic features of some CNS diseases. In particular, the treatment of primary CNS lymphoma with
corticosteroids can be associated with widespread tumor necrosis or infiltration by macrophages, which may limit
or misguide interpretation. Embolization of certain tumor types, especially meningiomas, may introduce histologic
changes in the neoplasm.
References
1. Burger PC, Scheithauer BW, Vogel FS. Surgical Pathology of the Nervous System and Its Coverings. 4
th
ed.
New York: Churchill Livingstone; 2002.
2. Perry A, Brat DJ. Practical Surgical Pathology: A Diagnostic Approach. Philadelphia: Elsevier; 2010.
3. McLendon RE, Rosenblum MK, Bigner DD, eds. Russell and Rubinstein's Pathology of Tumors of the
Nervous System. 7
th
ed. New York: Hodder Arnold; 2006.
4. Forsyth PA, Kelly PJ, Cascino TL, et al. Radiation necrosis or glioma recurrence: is computer-assisted
stereotactic biopsy useful? J Neurosurg. 1995;82:436-444.
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