• The retromolar trigone is "a triangular mucosal fold located posterior to the last mandibular molar and bound laterally by the ramus of the mandible and medially by the temporal crest" (Demir 2020)
• Accounts for 3.7 to 9.1% of squamous cell carcinomas that arise in the oral cavity (Kim 2021)
• Carries a worse prognosis than other oral cavity cancers due to unique location and oftentimes being diagnosed late in its course (Kim 2021)
• May invade mandible and maxilla, pterygoid muscles, masticator space, infratemporal fossa (Demir 2020)
• Reported to have 67.9% male to female ratio, average age of 64.7 years (Yao 2024)
• One diagnostic clue is the obliteration of buccal fat behind the parotid duct
• May spread via the pterygomandibular raphe which is located deep to the retromolar trigone
• The pterygomandibular raphe is an important anatomical marker in cases of retromolar trigone SCCa
  • The pterygomandibular raphe attaches superiorly to the pterygoid hamulus, allowing tumor spread to base of skull or masticator space
  • The pterygomandibular raphe attaches inferiorly to the mylohyoid line of the mandible allowing for tumor spread to the floor of mouth
• Lymph node involvement present in 21-55% of cases (Yao 2024)
• The main lymphatic drainge is into the superior-deep jugular lymph nodes (level II) (Horta 2016)

References

Comer JC, King RB, Harris AB, et al. Retromolar trigone squamous cell carcinoma: A population-based analysis of survival. Oral Oncol. 2022;127:105767. doi:10.1016/j.oraloncology.2022.105767

Yao Q, Xiong J, Zhou L, Zhao Z. Clinical characteristics and prognosis of patients with primary squamous cell carcinoma of the retromolar trigone: A SEER-based analysis. J Stomatol Oral Maxillofac Surg. 2024;125(2):101675. doi:10.1016/j.jormas.2023.101675

Kim HW, Kim MY, Kim CH. A systematic review of therapeutic outcomes following treatment of squamous cell carcinoma of the retromolar trigone. J Korean Assoc Oral Maxillofac Surg. 2021;47(4):291-314. doi:10.5125/jkaoms.2021.47.4.291

Demir UL, Öztürk Yanaşma H. Treatment Outcomes for Primary Retromolar Trigone Carcinoma: A Single Institution Experience. Turk Arch Otorhinolaryngol. 2020 Jun;58(2):87-92. doi: 10.5152/tao.2020.5153. Epub 2020 Jun 1. PMID: 32783034; PMCID: PMC7397542.

Horta, Ricardo MD, PhD; Nascimento, Ricardo MD; Silva, Alvaro MD; Amarante, José MD, PhD. The Retromolar Trigone: Anatomy, Cancer Treatment Modalities, Reconstruction, and a Classification System. Journal of Craniofacial Surgery 27(4):p 1070-1076, June 2016. | DOI: 10.1097/SCS.0000000000002625