Grading of cavernous sinus invasion by pituitary macroadenoma

Case contributed by Dr Elnur Mehdi

A coronal view of cavernous sinus and adjacent structures. Three lines pass through supra- and intracavernous parts of internal carotid artery (ICA):

  • medial line - connects the medial wall of ICAs
  • median line - crosses across the centers of ICAs
  • lateral line - touches the lateral wall of ICAs

Case Discussion

Knosp et al. offered a grading system for predicting invasion of the cavernous sinus (CS) by pituitary macroadenoma on the basis of MRI 1. This represents the parasellar extension of the tumour.

Briefly, the more laterally an adenoma grows and surrounds the internal carotid artery (ICA), the higher its grade level is. The grading is defined by the limits of tumour extension in relation to the carotid lines. These lines pass through supra- and intra-cavernous parts of ICA in coronal view. There are medial, median and lateral carotid lines.

  • grade 0: adenoma does not extend the medial carotid line
  • grade 1: adenoma crosses the medial line, but doesn't extend past the median line, or so-called "intercarotid" line
  • grade 2: tumor extends beyond the median line, but doesn't extend beyond the lateral line
  • grade 3: tumor extends beyond the lateral line
  • grade 4: tumor totally wraps around the intracavernous carotid artery

In 2015 Micko et al. subdivided grade 3 into 2:

  • 3A - the tumor extends to the lateral line superiorly (over ICA)
  • 3B - the tumor extends to the lateral line inferiorly (under ICA)
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Case information

rID: 29524
Published: 22nd Jul 2018
Last edited: 24th Jul 2018
Inclusion in quiz mode: Excluded

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