International Journal of Oral and Maxillofacial Surgery
Research PaperHead, Neck OncologyAutomatic upstaging of tongue squamous cell carcinoma with lateral extrinsic muscle involvement is not justified
Section snippets
Creation of a VHF-based anatomic atlas of extrinsic tongue musculature
The anatomy of the extrinsic tongue muscles was mapped in three dimensions using images from the Visible Human Project (VHP).7 The VHP obtained high-resolution computed tomography (CT) and MRI images prior to freezing, sectioning, and photographing two human cadavers (male 1994; female 1995). This produced three-dimensional (3D) datasets of the complete human anatomy, available free to the scientific community. The Visible Human Female (VHF) is the more comprehensive of the datasets.
Results
Fig. 1 demonstrates the final computer model to assist in extrinsic tongue muscle identification.
The demographic data of the 87 patients included in the study are summarized in Table 2. The mean age was 58 years (range 22–87 years). Of the 87 patients, 16 (18.4%) had superficial tumours not visible on MRI. These were designated as negative for extrinsic muscle involvement. Of the remaining 71 patients with positive extrinsic muscle tumour ingress, a total of 292 tumour-containing MRI slices
Discussion
The starting point of the study was the creation of a computer-based anatomical model on which to assess the accuracy of tumour staging of tongue tumours according to the TNM classification. The VHF provided intricate detail of the lingual musculature unaffected by formalin or shrinkage of tissues. Whilst the computer model was limited to data obtained from a single tongue, the close approximation to the classical anatomical texts of Abd-El-Malek and Miyawaki provided confirmation of anatomical
Funding
None.
Competing interests
None declared.
Ethical approval
Not required.
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Cited by (17)
TNM Classification: Are Cancers With Extrinsic Tongue Muscle Involvement Systematically T4a?
2021, Journal of Oral and Maxillofacial SurgeryCitation Excerpt :Our observations are in line with published data on the tongue as well as numerous studies conducted in humans and large primates using anatomic cadaveric dissections or radiological investigations in patients.10-12 Boland et al5 using the Visible Human Project6,7 and high-resolution computed tomography and magnetic resonance imaging images showed that the styloglossus and the hyoglossus were situated 1.3 to 2.9 mm and 2.93 to 4.33 mm, respectively, under the lingual mucosal surface. According to Takemoto,10,11 in humans and nonhuman primates, the musculature comprises inner and outer layers.
Impact of extrinsic tongue muscle invasion on stage migration in AJCC 8th edition staging of oral cavity carcinoma
2020, Oral OncologyCitation Excerpt :However, the relevance of its impact as an independent prognostic indicator has been challenged. Boland et al. [5] utilized magnetic resonance images (MRI) to determine that lateral tumors with invasion of the styloglossus or hyoglossus can represent superficial tumors that show no association with occult nodal disease or disease-related survival. This study does not address the hypothesis that EMI may represent a means by which the tumor can overcome normal fascial planes resulting in more aggressive spread, even of superficial tumors.
Magnetic resonance imaging findings of styloglossus and hyoglossus muscle invasion: Relationship to depth of invasion and clinical significance as a predictor of advisability of elective neck dissection in node negative oral tongue cancer
2019, European Journal of RadiologyCitation Excerpt :There has been discussion about whether the invasion of styloglossus and hyoglossus muscles is truly reflected by the tumor staging. Boland et al. reported that because these muscles are located on the superficial layer from the mucosal surface of the tongue, their use as inclusion criteria in the T4a staging does not appear to be justified based upon their anatomical position [29]. The limitation was that the study was done using a computer model based on only one patient.
Styloglossus muscle: A critical landmark in head and neck oncology
2018, Annales Francaises d'Oto-Rhino-Laryngologie et de Pathologie Cervico-FacialeStyloglossus muscle: a critical landmark in head and neck oncology
2018, European Annals of Otorhinolaryngology, Head and Neck DiseasesCitation Excerpt :Due to the radiographic staging criteria mentioned above, this extreme proximity with the mucosa of the lateral oropharynx leads to a frequent radiographic up-staging. Based on the radiographic evidence of SG muscle involvement, Boland et al. [21] noted that up to 52% of cases clinically considered as T1-3 have been shown to be reclassified as T4a. However, the validity and relevance of radiographic up-staging is this scenario is controversial.
“Deep Extrinsic Muscle Involvement” Is a Fallacy in the American Joint Committee on Cancer's Seventh Edition of Tumor Staging of Oral Cavity Cancers
2018, Journal of Oral and Maxillofacial SurgeryCitation Excerpt :The true implication of extrinsic muscle invasion has seldom been published in the literature. Boland et al7 reported the findings of 87 patients with tongue carcinoma who had preoperative MRI. Of these patients, 71 had positive extrinsic muscle involvement on imaging.