Carcinoma of Retromolar Trigone

Carcinoma of Retromolar Trigone

Carcinoma of Retromolar Trigone

A case of carcinoma of Retromolar Trigone operated with Resection Selective Neck Dissection and Radial Forearm free flap Reconstruction.


retromolar trigone

The retromolar trigone is a triangular area bounded by temporal crest on the medial side, anterior border of ramus on the lateral side and covered by gingival mucosa. It is positioned between the lower third molar and the ascending ramus of the mandible.

Retromolar trigone squamous cell carcinoma is relatively rare but aggressive malignancy and due its spatial relationship with the surrounding structures, it has always remained a challenge from an oncologic point of view.


A 41 year-old male patient was referred to Dr. Mathan Mohan with a chief complaint of pain in left lower back tooth region of 3 months duration. The patient also gave a history of difficulty in mouth opening and swallowing.

Clinical presentation

Physical examination revealed a lesion behind the third molar.  Dr. Mathan supplemented clinical examination with imaging modalities to evaluate regional and distant metastasis. MRI revealed soft tissue extension, masticator space involvement and infratemporal fossa invasion which are all characteristic features of retromolar trigone squamous cell carcinoma.

Treatment and prognosis

Upon histopathological proof of squamous cell carcinoma, Dr. Mathan nominated the patient for surgery with Resection Selective Neck Dissection (SND) and Radial Forearm free flap Reconstruction followed by adjuvant chemotherapy.

Selective Neck Dissection (SND)

Selective Neck Dissection (SND)

Selective neck dissections involve the resection of three or four levels according to the site of the primary cancer. The procedure entails removal of cervical lymph nodes only from selected levels of the neck. It is usually done as an elective neck dissection (END) in the absence of clinically apparent cervical metastases when the risk of having occult cervical nodal metastases is thought to exceed more than 15%.

Although it is a technically demanding procedure due to poorer exposure, Dr. Mathan’s sound knowledge of the 3- dimensional anatomy of the neck resulted in a successful dissection. Level I II and III nodes were removed as they posed the greatest risk of metastases. Removal of these lymph nodes for oncologic reasons has demonstrated superior local control rates and post-treatment functionality.

Radial Forearm free flap Reconstruction

Radial Forearm free flap Reconstruction

Radial forearm free flap surgery is a versatile and proven technique that is widely adopted for reconstruction of the oral, oropharyngeal and hypopharyngeal lining. The donor area of radial forearm is thin and vascular enough to allow flap folding and shaping to reconstruct complex defects.

The size of the flap is determined before surgery and marked on the forearm, often with a template from the estimate of the defect size.


Although retromolar trigone squamous cell carcinoma is a rare entity with late presentation, Dr. Mathan ensured the complete removal of the tumour with appropriate margins. After operating with Resection Selective Neck Dissection of the affected side, Radial Forearm Free Flap was used for reconstruction.

These tumors have extremely high risk of occult metastasis so Elective Neck Dissection (END) is mandatory for oncological control. The patient was supported by chemotherapy to improve the prognosis.

Dr. Deepak Velu

Dr. Deepak is associated with Dr. Mathan for past 5 years with special interest in Maxillofacial trauma and specialised in managing TMJ abnormalities from replacement surgeries to advanced arthroscopy procedure. His care toward the patient's welfare is audible.