Laryngeal SCC of the Subglottis
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Hello everyone, Sidney Levy here discussing
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laryngeal squamous cell malignancy.
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We've discussed supraglottic and glottic tumors, and
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we've used an example of a large transglottic tumor.
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I'd like to round off our discussion
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by mentioning the subglottis.
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Subglottic tumors carry imaging features
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of being either infiltrative or exophytic.
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and tend to narrow the subglottis,
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which is usually a smooth, round contour.
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So, one of the first indicators of a subglottic
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tumor is an irregularity to the normal
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ovoid or round contour of the subglottis.
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So, as you can see here, this is abnormal.
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We are well and truly into the subglottis
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by this stage, and we should have a
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nice rounded contour, smooth contour.
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There shouldn't be any bulges or
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projections like there is here.
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The tumors themselves are similar
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to other laryngeal tumors.
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T1 hypointense to intermediate, T2 intermediate
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signal enhancement, which may be variable,
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maybe homogeneous or heterogeneous.
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You need to make a comment on the status of the cartilages,
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and the cartilage which is most at
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threat at the level of the subglottis is the
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cricoid cartilage, which is demonstrated here.
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In this case, the tumor is not clearly
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involving the cricoid cartilage.
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CT is important for assisting in the assessment
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of cartilage erosion or involvement and
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should be obtained in quiet respiration.
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It is important not to ascribe cartilage
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involvement when sclerosis only is present.
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So what I mean by that is if there is
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sclerosis of cartilage, but there is no destruction,
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you shouldn't say that the cartilage
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is, is, is clearly involved.
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With regards to subglottic tumors, nodal spread
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is uncommon in a similar fashion to glottic tumors
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because there is a paucity of lymphatic supply.
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If there is locally advanced disease,
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you may see involvement of regional
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lymph nodes in the superior mediastinum.
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So level 7 paratracheal lymph nodes are quite
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commonly involved by subglottic tumors if
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there has been locally advanced disease.
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Afterwards, you may look at levels 3 and 4 as well.
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Subglottic tumors tend to present late
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and are often associated with cartilage
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invasion and extralaryngeal extension.
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So if you see tissue which is internal to the cricoid
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ring, you should consider subglottic tumor and it may
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require direct inspection by an otorhinolaryngologist.
Sidney Levy, PhD, MBBS
Radiologist and Nuclear Medicine Specialist
I-MED
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