Oral cavity neoplasms imaging staging

Oral cavity neoplasms imaging staging Poster No.: C-1751 Congress: ECR 2010 Type: Educational Exhibit Topic: Head and Neck Authors: L. Oleaga, M. Squarcia, S. Capurro, J. Berenguer, T. Pujol, M. Olondo, C. Cardenal; Barcelona/ES Keywords: oral cavity, oral tongue, head and neck tumors DOI: 10.1594/ecr2010/C-1751 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 52

Learning objectives 1-To review the anatomy of the oral cavity 2-To depict imaging landmarks used for staging oral cavity neoplasms 3-To review the TNM staging system applied to imaging classification of oral cavity tumors Background The oral portion of the upper aerodigestive tract is divided in two major components: the oral cavity and the oropharynx. The oral cavity is anterior to the oropharynx and separated from it by a ring of structures that includes the soft palate, anterior tonsilar pillars and the circumvallate papillae. The circumvallate papillae divide the tongue into the anterior two thirds, called the oral tongue and the posterior third, named the tongue base. The oral tongue is located in the oral cavity and the base tongue is in the oropharynx. The oral cavity contains the oral tongue, hard palate, the buccal mucosa, the floor of the mouth and the retromolar trigone. Imaging findings OR Procedure details ORAL TONGUE The oral tongue comprises the anterior two thirds of the tongue, anterior to the circumvallate papillae. It is formed by two halves separated by a midline septum. Page 2 of 52

The midline septum lies between the paired genioglossus muscles and extends into the floor of the mouth. The tongue is formed by intrinsic and extrinsic muscles. The intrinsic tongue muscles are formed by four interdigitating bundles of muscle fibers: superior and inferior longitudinal, vertical and transverse. Page 3 of 52

Fig.: Oral tongue (intrinsic muscles) Intrinsic muscles cp- circumvallate papillae Page 4 of 52

References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN The extrinsic tongue muscles include the genioglossus, hyoglossus and styloglossus. Page 5 of 52

Fig.: Oral tongue (extrinsic muscles)/floor of the mouth. Sublingual and submandibular spaces gg- genioglossus hg- hyoglossus mh- mylohyoid muscle slsublingual space sm- submandibular space References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN The hypoglossal nerve supplies motor inervation to both the intrinsic and extrinsic tongue musculature. The lingual nerve, a branch of trigeminal nerve, carries sensory taste fibers from the anterior two thirds of the tongue and the glossopharyngeal nerve carries similar fibers from the posterior third of the tongue. HARD PALATE The hard palate is formed by the horizontal plates of the palatine bones. It is the rigid segment of the oral cavity. The mucous membrane of the hard palate is tighten to the periosteum of the palatine bones. The soft palate is attached to the posterior aspect of the hard palate. Page 6 of 52

Fig.: Hard palate hp-hard palate References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN ORAL MUCOSA The mucosal area of the oral cavity lines the entire cavity; there is no visible separation between the mucosal area of the oral cavity and the adjacent oropharynx. The mucosa lines the buccal, gingival, palatal, sublingual and lingual surfaces. Page 7 of 52

The depth of the mucosal area of the oral cavity is only a few millimeters. There is no visible separation between the mucosal area of the oral cavity and the adjacent oropharynx. The epithelial lining of the oral cavity consist of no keratinized, stratified, squamous epithelium. Subepithelial minor salivary glands are found throughout the inner surface of the buccal mucosa. Page 8 of 52

Fig.: Buccal mucosa oph- oropharynx oc- oral cavity References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN FLOOR OF THE MOUTH Page 9 of 52

The floor of the mouth is a U-shaped muscular sling composed by the mylohyoid muscle. Fig.: Floor of the mouth gg- genioglossus hg- hyoglossus mh- mylohyoid muscle References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN The mylohyoid muscle serves as a muscular hammock strung between the medial aspects of the mandibular bodies. It separates the sublingual space (SLS) from the submandibular space (SMS), they represent two important landmarks in the floor of the mouth. Page 10 of 52

Fig.: Oral tongue (extrinsic muscles)/floor of the mouth. Sublingual and submandibular spaces gg- genioglossus hg- hyoglossus mh- mylohyoid muscle slsublingual space sm- submandibular space References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 11 of 52

It is covered by squamous mucosa and continuous with the suprahyoid spaces. It is bounded anteriorly by the gingiva of the mandible and posteriorly by the anterior tonsillar pillar. The SLS is located superomedial to the myelohyoid muscle; it contains the anterior extension of the hyoglossus muscle, the lingual nerve, cranial nerves IX and XII, lingual artery and vein, the sublingual glands and ducts, deep portion of submandibular gland and Wharton's duct. The hyoglossus muscle is an important surgical landmark as it separates the Wharton s duct and the hypoglossal and lingual nerves, which lie lateral to the muscle, from the medially positioned lingual artery and vein. The SMS is inferolateral to the myelohyoid muscle and superior to the hyoid bone. It contains the anterior belly of the dygastric muscle, the superficial portion of the submandibular gland, the facial vein and artery and the inferior loop of XII cranial nerve. RETROMOLAR TRIGONE The retromolar trigone is a triangular area of mucosa covering the anterior aspect of the ascending ramus of the mandible, posterior to and between the upper and lower third molar teeth. The mucous membrane of the retromolar trigone and anterior tonsillar pillars blend together. Page 12 of 52

Fig.: Retromolar trigone rmt- retromolar trigone bm-buccinator muscle spcm- superior constrictor muscle References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 13 of 52

The mucosa and submucosa of the retromolar trigone form a layer that moves with respect to the underlying pterygomandibular raphe. The pterigomandibular raphe is a thick fascial band that extends between the hamulus of the medial pterygoid plate and the mylohyoid ridge of the mandible. Page 14 of 52

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Fig.: Pterigomandibular raphe ptmr- pterigomandibular raphe bm- buccinator muscle spcm- superior constrictor muscle References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN The buccinator and superior pharyngeal constrictor muscles both originate from the pteygomandibular raphe. Malignancies arising in the retromolar trigone may extend cephalad along the pterygomadibular raphe to the buccinator space or they may reach caudally the mylohyoid muscle and the floor of the mouth. MALIGNANT NEOPLASMS Squamous cell carcinoma account for > 90% of all malignant lesions of the oral cavity. Risk factors include alcohol and tobacco abuse, it affects primarily middle-aged men. The five subsites of squamous cell carcinoma of the oral cavity are the oral tongue, the floor of the mouth, the retromolar trigone, the oral mucosa and the hard palate. Squamous cell carcinomas of the oral cavity tend to spread locally with invasion of surrounding structures, and the risk and patterns of lymphatic spread to regional cervical nodes vary with the anatomic location of the primary tumor. Certain anatomic subsites, such as the oral tongue and floor of the mouth, are rich in lymphatics, and tumors of these areas have a higher risk of nodal metastases. Distant metastasis is not common, but tumors such as adenoid cystic carcinoma have a higher predilection for pulmonary metastases. T Staging for primary squamous cell carcinoma of the oral cavity T1- Tumor is 2cm or less in its greatest dimension T2- Tumor more than 2cm but not more than 4cm in its greatest dimension T3- Tumor more than 4cm in its greatest dimension T4- Tumor invades adjacent structures, including mandible, maxilla, skin, extrinsic tongue muscles, and soft tissues of the neck Page 16 of 52

There are important aspects to be assessed on imaging which influence the treatment and prognosis of the patients. Those factors include: tumor size, integrity of the mandible, invasion of the neurovascular pedicle, involvement of the base of the tongue, extent of tumour in relation to the midlin, invasion of the pterygomandibular raphe, buccinator space and lymph nodes. ORAL TONGUE TUMORS Fig.: Axial contrast enhanced CT T4 squamous cell carcinoma of the left oral tongue (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 17 of 52

Fig.: Axial contrast enhanced CT Squamous cell carcinoma of oral tongue on the left crossing the lingual septum (ls) into contralateral tongue (arrow) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN HARD PALATE TUMORS Page 18 of 52

Fig.: Right hard palate mass with invasion of the upper alveolar ridge(arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN ORAL MUCOSA TUMORS Page 19 of 52

Fig.: Axial FATSAT T2W MRI Squamous cell carcinoma of lingual mucosa, invading the extrinsic muscles of the tongue with posterior extension to the lateral pharyngeal wall (asterisk). Bilateral IIA lymph nodes References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 20 of 52

Fig.: Axial contrast enhanced CT T4 squamous cell carcinoma of the gingival mucosa on the right eroding the maxillary alveolar ridge References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 21 of 52

Fig.: Figure 16- A-Axial T1W MRI. B-Coronal T1W MRI Lingual mucosa tumor with right mandibular invasion (arrows). High signal intensity of the normal bone marrow on the left (asterisk) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN FLOOR OF THE MOUTH TUMORS Page 22 of 52

Fig.: Axial contrast enhanced CT T2 squamous cell carcinoma of the tongue invading the sublingual space, hioglosus muscle and floor of the mouth. Normal sublingual space (sl), hyoglosus muscle (hg) and mylohyoid muscle (mh) on the left. References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 23 of 52

Fig.: Axial contrast enhanced CT T4 squamous cell carcinoma of mandibular alveolar ridge, large area of bone destruction of mandible in both surfaces medial and lateral (asterisk). Invasion of mylohyoid muscle. Normal mylohyoid muscle on the right (mh) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 24 of 52

RETROMOLAR TRIGONE TUMORS Fig.: Axial contrast enhanced CT T1 right retromolar trigone mass (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 25 of 52

Fig.: Axial contrast enhanced CT T2 left retromolar trigone mass (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 26 of 52

Fig.: Figure 18- A-Axial T1W MRI. B-Axial FATSAT T1W gadolinium enhanced MRI. C- Axial DW MRI. D- ADC map A- Left trigone mass with mandibular invasion (arrows) B- Enhancement of the tumor and mandibular bone marrow (arrows) C- Increased signal of the tumoral mass on DW image (arrows) D- Restriction of the tumoral mass on the ADC map (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN LYMPHATIC SPREAD Page 27 of 52

Malignant tumors of the oral cavity metastasize to ipsilateral level IB, level IIA an IIB or to contralateral lymph nodes. The incidence of lymph node metastasis is 10-30% for early disease and 50-70% for late disease. Imaging is necessary to assess deep submucosal extent and for evaluation of lymph node chains. N staging for oral cavity tumors Nx Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2 Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension; or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N2a Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension N2c Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N3 Metastasis in a lymph more than 6 cm in greatest dimension Lymph nodes level classification based on imaging methods Arch otolaryngol Head Neck Surg 1999;125:388-396 AJR 2000;174:837-844 Page 28 of 52

Level IA, IB (reference posterior border of submandibular gland) Level IIA, IIB (reference hyoid bone) Level III (reference crycoid bone) Level IV (reference anterior scalene muscle, lateral border of carotid artery) Level V (reference posterior border of sternocleidoimastoid muscle) Level VI (reference medial border of carotid artery and sternal bone) Level VII (superior mediastinal nodes) Retrofaringeal nodes Supraclavicular nodes Fig.: Figure 17- A-Axial FATSAT T2W MRI. B-Axial FATSAT T2W. C-Axial Diffusion Weighted (DW) MRI A- Squamous cell carcinoma of the left trigone (arrows) BBilateral IIA metastasic lymph nodes (arrows) C- Bilateral IIA metastasic lymph nodes with increased signal on DW image (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Page 29 of 52

Fig.: Figure 19- Axial (A) and Sagital (B) Contrast enhanced CT Left level IIB metastasic lymph nodes with necrosis in a patient with left oral tongue carcinoma (arrows) References: L. Oleaga; Radiology, Hospital Clinic, Barcelona, SPAIN Images for this section: Page 30 of 52

Fig. 1: Oral tongue (intrinsic muscles) Intrinsic muscles cp- circumvallate papillae Page 31 of 52

Fig. 2: Oral tongue (extrinsic muscles)/floor of the mouth. Sublingual and submandibular spaces gg- genioglossus hg- hyoglossus mh- mylohyoid muscle sl- sublingual space smsubmandibular space Page 32 of 52

Fig. 3: Hard palate hp-hard palate Page 33 of 52

Fig. 4: Buccal mucosa oph- oropharynx oc- oral cavity Page 34 of 52

Fig. 5: Floor of the mouth gg- genioglossus hg- hyoglossus mh- mylohyoid muscle Page 35 of 52

Fig. 6: Retromolar trigone rmt- retromolar trigone bm-buccinator muscle spcm- superior constrictor muscle Page 36 of 52

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Fig. 7: Pterigomandibular raphe ptmr- pterigomandibular raphe bm- buccinator muscle spcm- superior constrictor muscle Fig. 8: Axial contrast enhanced CT T4 squamous cell carcinoma of the left oral tongue (arrows) Page 38 of 52

Fig. 9: Axial contrast enhanced CT Squamous cell carcinoma of oral tongue on the left crossing the lingual septum (ls) into contralateral tongue (arrow) Page 39 of 52

Fig. 10: Right hard palate mass with invasion of the upper alveolar ridge(arrows) Page 40 of 52

Fig. 11: Axial FATSAT T2W MRI Squamous cell carcinoma of lingual mucosa, invading the extrinsic muscles of the tongue with posterior extension to the lateral pharyngeal wall (asterisk). Bilateral IIA lymph nodes Page 41 of 52

Fig. 12: Axial contrast enhanced CT T4 squamous cell carcinoma of the gingival mucosa on the right eroding the maxillary alveolar ridge Page 42 of 52

Fig. 13: Figure 16- A-Axial T1W MRI. B-Coronal T1W MRI Lingual mucosa tumor with right mandibular invasion (arrows). High signal intensity of the normal bone marrow on the left (asterisk) Page 43 of 52

Fig. 14: Axial contrast enhanced CT T2 squamous cell carcinoma of the tongue invading the sublingual space, hioglosus muscle and floor of the mouth. Normal sublingual space (sl), hyoglosus muscle (hg) and mylohyoid muscle (mh) on the left. Page 44 of 52

Fig. 15: Axial contrast enhanced CT T4 squamous cell carcinoma of mandibular alveolar ridge, large area of bone destruction of mandible in both surfaces medial and lateral (asterisk). Invasion of mylohyoid muscle. Normal mylohyoid muscle on the right (mh) Page 45 of 52

Fig. 16: Axial contrast enhanced CT T1 right retromolar trigone mass (arrows) Page 46 of 52

Fig. 17: Axial contrast enhanced CT T2 left retromolar trigone mass (arrows) Page 47 of 52

Fig. 18: Figure 18- A-Axial T1W MRI. B-Axial FATSAT T1W gadolinium enhanced MRI. C- Axial DW MRI. D- ADC map A- Left trigone mass with mandibular invasion (arrows) B- Enhancement of the tumor and mandibular bone marrow (arrows) C- Increased signal of the tumoral mass on DW image (arrows) D- Restriction of the tumoral mass on the ADC map (arrows) Page 48 of 52

Fig. 19: Figure 17- A-Axial FATSAT T2W MRI. B-Axial FATSAT T2W. C-Axial Diffusion Weighted (DW) MRI A- Squamous cell carcinoma of the left trigone (arrows) B- Bilateral IIA metastasic lymph nodes (arrows) C- Bilateral IIA metastasic lymph nodes with increased signal on DW image (arrows) Fig. 20: Figure 19- Axial (A) and Sagital (B) Contrast enhanced CT Left level IIB metastasic lymph nodes with necrosis in a patient with left oral tongue carcinoma (arrows) Page 49 of 52

Conclusion Imaging is necessary to assess deep submucosal extent and for evaluation of lymph node chains. Important aspects to demonstrate on imaging are tumor size, integrity of the mandible, the extent of tumour in relation to the midline, invasion of the pterygomandibular raphe and buccinator space. Those factors can change the treatment and prognosis of the patient. KEY POINTS TO TAKE HOME 1- The oral cavity contains the oral tongue, hard palate, the buccal mucosa, the floor of the mouth and the retromolar trigone. 2- The oral tongue comprises the anterior two thirds of the tongue, anterior to the circumvallate papillae. 3- The intrinsic tongue muscles are formed by four interdigitating bundles of muscle fibers: superior and inferior longitudinal, vertical and transverse. 4- The extrinsic tongue muscles include the genioglossus, hyoglossus and styloglossus. 5- The mucosal area of the oral cavity lines the entire cavity; there is no visible separation between the mucosal area of the oral cavity and the adjacent oropharynx. 6- The floor of the mouth is a U-shaped muscular sling composed by the mylohyoid muscle. 7- The mylohyoid muscle serves as a muscular hammock strung between the medial aspects of the mandibular bodies. It separates the sublingual space (SLS) from the submandibular space (SMS), they represent two important landmarks in the floor of the mouth. 8- The hyoglossus muscle is an important surgical landmark as it separates the Wharton s duct and the hypoglossal and lingual nerves. Page 50 of 52

9- The retromolar trigone is a triangular area of mucosa covering the anterior aspect of the ascending ramus of the mandible, posterior to and between the upper and lower third molar teeth. 10- Malignancies arising in the retromolar trigone may extend cephalad along the pterygomadibular raphe to the buccinator space or they may reach caudally the mylohyoid muscle and the floor of the mouth. 11- Squamous cell carcinoma account for > 90% of all malignant lesions of the oral cavity. 12- Imaging is necessary to assess deep submucosal extent and for evaluation of lymph node chains. 13- Important aspects to demonstrate on imaging are: a-tumor size b-integrity of the mandible c-extent of tumour in relation to the midline d-invasion of the pterygomandibular raphe and buccinator space Personal Information Laura Oleaga Radiology Department Hospital Clinic Barcelona. Spain lauraoleaga@gmail.com Page 51 of 52

References 1- Lenz M., Greess H., Baum U., Dobritz M., Kersting-Sommerhoff B. Oropharynx, oral cavity, floor of the mouth: CT and MRI. Eur J Radiol. 2000; 33:203-15. 2- Becker M. Oral cavity, oropharynx, and hypopharynx. Semin Roentgenol 2000; 35:21-30. 3- Yousem D.M., Chalian A.A. Oral cavity and pharynx. Radiol Clin North Am. 1998; 36:967-81. 4- Mukherji S.K., Castillo M. Normal cross-sectional anatomy of the nasopharynx, oropharynx, and oral cavity. Neuroimaging Clin N Am. 1998; 8:211-8. 5- Laine F.J., Smoker W.R. Oral cavity: anatomy and pathology. Semin Ultrasound CT MR. 1995; 16:527-45. 6- Mukherji S.K., Castelijns J., Castillo M. Squamous cell carcinoma of the oropharynx and oral cavity: how imaging makes a difference. Semin Ultrasound CT MR. 1998; 19:463-75. 7- Sigal R. Oral cavity, oropharynx, and salivary glands. Neuroimaging Clin N Am. 1996; 6:379-400. 8- Stambuk.E.H., Karimi S., Lee N., Patel S.G. Oral cavity and oropharynx tumors. Radiol Clin N Am 2007; 45:1-20 20 Page 52 of 52