ORAL CAVITY: ANATOMY AND PATHOLOGIES Alexandra Borges, MD COI Disclosure Instituto Português de Oncologia de Lisboa I have nothing to disclose Champalimaud Foundation Lisbon, Portugal ECHNNR 2021 ECHNNR 2021 MR ANATOMY LEARNING OBJECTIVES • Become familiar with OC anatomy and the importance of using adequate terminology when reporting OC studies NASOPHARYNX NASAL CAVITY • Learn how to tailor imaging studies • Understand the different patterns of malignant tumor spread according to the different tumor subsites OROPHARYNX ORAL CAVITY HYPOPHARYNX BOUNDARIES CONTENTS: ORAL TONGUE Superior: • hard palate • superior alveolar ridge Inferior: • floor of the mouth • inferior alveolar ridge ITM Laterally: • cheeks and buccal mucosaosa Anterior: • Lips Posterior: • oropharynx ORAL TONGUE: Extrinsic tongue muscles EM: Styloglossus tongue retraction and elevation Styloglossus Palatoglossus Hyoglossus SG Geniglossus HG GG CN XII CN X EM: Palatoglossus elevation of the tongue EM: Hyoglossus tongue depression and retraction EM: Genioglossus tongue protrusion ORAL TONGUE: Extrinsic muscles GG GH TONGUE INNERVATION ORAL CAVITY IX sensitive and Spatial subdivision taste CN X Motor • Mucosal area • Tongue root • Sublingual space CN XII Motor • Submandibular space Lingual nerve: Sensitive (branch of V3) • Buccomasseteric region Taste (chorda tympani) ORAL MUCOSAL SPACE ROOT OF THE TONGUE 1. Lips 2. Gengiva (sup. alveolar ridge) 3. Gengiva (inf. alveolar ridge) 4. Buccal 5. Palatal 6. Sublingual/FOM 7. Retromolar trigone GG 8. Tongue ROT BOT Vestibule GH Mucosa (NKSSE) Minor salivary glandss SUBLINGUAL & SUBMANDIBULAR SPACES FLOOR OF THE MOUTH SL MH ABD SM V3 Mylohyoid branch MYLOHYOID CLEFT SUBLINGUAL SPACE WD SUBMANDIBULAR SPACE SUBLINGUAL SPACE CONTENTS ITM SLS HG SMG SLG WD IX SLG LN XII LA GH D WD Medial comp.- vascular pedicle, CN IX Lateral comp.- Sublingual gland, Wharton’s duct, lingual nerve and CN XII SUBMANDIBULAR SPACE: Contents SUBMANDIBULAR SPACE: Pitfalls SMG SMG FA PG FV SL SMG DL SMG MR ANATOMY: The retromolar trigone MR ANATOMY: The retromolar trigone BS OC MS OPh MR ANATOMY: The buccal space THE BUCCAL SPACE M B CHOICE OF IMAGING MODALITY US • Superficial lesions (SL and SM spaces) • Clinical presentation • Evaluation of cervical LNs • Specific contra-indications • Evaluation of tumor thickness (DOI) • Availability •FNAC/biopsy US IMAGING PROTOCOL New AJCC 2018. DOI! US • High frequency pediatric US probe (7- 15Mhz) • “Hockey stick” probe, angulated or basculating head • Useful for anteriorly located tumors of the OC Courtesy of Frank Pameijer, NE CT MRI IMAGING PROTOCOL • Wider accessibility • No ionizing radiation • Faster acquisition • Better for soft tissue extent, MDCT • Better for trauma and bone marrow and PNS MRI • Volumetric acquisition (from SB to clavicles) • High field magnet (1.5 or 3T) infection • Less affected by dental • IV contrast (single or double bolus 60-80 ml; • Sinergy head and neck coil coil • Better for cortical bone amalgam artifact 70 sec delay; 2cc/sec) • 3mm thick slices /1-2mm interslice • Contiguous 3mm reconstructions (ax, cor, sag) assessment (dental CT) gap • Soft tissue and HR bone algorithm • Sequences: T1W, T2W, FS T2W (STIR, Drawbacks • “Puffed cheeks” (Oral tongue/ palate; SPAIR) gengiva/ buccal mucosa) • Dental artifacts • Motion artifacts • 3D CE FST1W (VIBE) • DWI and PWI (DCE) • Contra-indications for • General MR contraindications • FS T2/ DWI Vs FS CE T1W iodinated contrast Spectral CT • Better soft tissue resolution (less contrast Spatial/ temporal resolution administration) • Subtraction images (iodine maps) • 0.6/0.1 • 0. 1/0.05 (>S/N) IMAGING PROTOCOL BUCCAL INSUFFLATION Do we really need gadolinium? FS CE T1W FS T2W OC PATHOLOGY PATHOLOGY Clinical presentation MUCOSAL LESIONS SUBMUCOSAL LESIONS • Infection • Pseudomasses •Trauma • Congenital/ developmental • Neoplasms (SCC) • Infectious/inflammatory • Submucosal neoplasms (mesenchymal, minor salivary glands, lymphoid tissue) INFECTION IMAGING THE ORAL CAVITY WHY? • Dental infection/ manipulation • Determine the deep extent of • Perforating wound epithelial lesions • Salivary stasis (stones, stenosis, • Detect and characterize neoplasm) submucosal lesions • Goals of imaging: • Detect lesions in clinically – Determine the etiology – Evaluate the extent occult spaces – Depict drainable fluid collections • Stage and follow-up – Document the presence of gas malignancies – Evaluate airway integrity Odontogenic infection LUDWIG’S OR VINCENT’S ANGINA • Cellulitic process of the gengivobuccal mucosa • Bilateral spread to sublingual space and FOM INFECTION: Sialolithiasis RANULA OC malignancies OC malignancies some useful clues • SCC (90%)> MSGT>lymphoma>sarcoma (Rhabo/lipo/synovial) • LN involvement of OC tumors: • Bone tumors (odontogenic and non-odontogenic malignancies) • Levels I and II • SCC risk factors: • Rate of LN involvement depends on the stage of the • Alcohol, tobacco, repeated trauma 1ary tumor • HPV infection (p16 strain): 25% • Higher incidence of LN metastasis: • 8 different subsites: • FOM and RMT (50%)> tongue (40%)> buccal mucosa • Lip> tongue> FOM> gengiva > bucal>RMT> palate • Rare for lip and palatal tumors • Different: • Symptoms, routes of spread • Perineural spread (clinically silent): • Lymphatic drainage pathways • Tumors close to neurovascular bundles • Surgical approaches • FOM, RMT, gengiva (V3 and V2, rarely CNs XII and VII) • Prognosis BONE INVASION PATHWAYS OF TUMOR SPREAD • Limited by the periosteum • Cortical erosion TYPE OF SPREAD: DETECTION: • Invasion of the medullary cavity: • Mucosal spread • Clinical inspection – Through cortical bone • Submucosal – Through the mandibular/mental • Along muscle shafts MR foramina • PNS – Through alveolar sockets • Through bone • CT (dental scan/ CBCT)/MR CT- underestimates bone invasion (PPV) • Lymphatic (LN mets) • US (FNAC), PET-CT Dentascan- 95% sens, 79% spec, 87% PPV, 92% NPV • Hematogenous (distant mets) • FDG-PET-CT MR- overestimates bone invasion (NPV) DWI! Impact on treatment SCC Inferior lip (key review areas) Skin infiltration Bone invasion and PNS V3 DOI 4mm: prophylactic LN Inferior spread: FOM/ Sublingual space/tongue root Tongue dissection • Second most common OC location • Ventrolateral surface • US; MR>CT HGT • Key review areas: Posterior spread: Anterior tonsillar pillar and BOT 9 Midline raphe 9 Neurovascular bundle 9 Lymphatic spread: ATT skip nodes! TG Gingiva superior alveolar ridge GINGIVA/ ALVEOLAR RIDGE Maxilla/Pterygoid plates/ buccal / masticator space/ check palatine nerves, PPF and V2 • Non-healing ulcer/ ill-fitting dentures • Bone invasion quite common (Dental CT) • Check mental and mandibular forâmen! FOM BUCCAL MUCOSA • May present as a submandibular or sublingual lump (DDx with LN mets!) • High incidence of occult LN metastases (skip LNs level IV!) • Inner aspect of cheeks and lips • Glosso-milohyoid gap • Cheek insufflation • Neurovascular bundle • Poor prognosis • Buccal fat/ Stenson’s duct/ RMT Post-obstructive sialadenitis Invasion of the buccal space RETROMOLAR TRIGONE Mandible/ MS/ PMR/ pterygoid plates/ pharyngeal wall • Late presentation (trismus) • Key review areas: Buccal/ masticator/FOM/ PMR to lat pharyngeal wall Mandible and maxilla/ masticator space/ buccal space HARD PALATE CONGENITAL/ DEVELOPMENTAL • Incidence of SCC equals that of MSGT • High propensity for PNS (lesser • Embryonic anomalies related to the TGD or to and greater palatine nerves) the branchial apparatus • Persistent ectodermal remnants (epidermoid and dermoid cysts) • Vasculo-lymphatic malformations Case courtesy of Bert de Foer Lingual Thyroid Dermoid cysts: Epidermoid, dermoid, teratoid FOM>tongue>sublingual space Vascular malformations Pseudotumor Torus palatini Pseudotumor: Denervation atrophy THANK YOU FOR LISTENING!.