Abstract
At our institute, between 1990 and 2008, lateral retropharyngeal node (LRPN) metastasis was found in two patients with squamous cell carcinoma of the buccal mucosa. Primary tumors had invaded from the posterior part of the buccal mucosa. On sectional images, metastatic nodes, measuring 17 × 12 mm and 15 × 12 mm in size, were detected in the retropharyngeal space on the affected side. This study analyzed these two cases plus other four cases with buccal mucosa cancers developing LRPN metastasis reported in Japanese articles and/or proceedings, with an emphasis on the causal lymphatic pathways and clinical characteristics. Carcinoma of the posterior part of the buccal mucosa and/or retromolar trigone may easily invade the buccinator muscle and pterygomandibular raphe to which the buccinator muscle and superior constrictor muscle attach. Moreover, the pterygomandibular raphe attaches to the hamular notch, with which the tensor veli palatini muscle is associated. Between the tensor veli palatini muscle and the levator veli palatini muscle, the afferent lymphatic channels run to the LRPN, as indicated in a previous report. Speculating from these anatomical correlations, LRPN metastasis may derive from the area of the pterygomandibular raphe, via the afferent lymphatic channels through the superior constrictor muscle or beside the tensor veli palatini muscle. In our own cases and two other cases with T4 carcinomas, the retromolar trigone and the pterygomandibular raphe were involved on sectional images or were clinically suspected. In two of the T4 cases, LRPN metastases were revealed on the initial sectional images. On the other hand, in our own cases with T2 carcinomas and the one case with a T4 carcinoma, LRPN metastases developed between five and eight months postoperatively.
Therefore, whenever carcinomas of the buccal mucosa develop to the retromolar trigone and the pterygomandibular raphe, the lateral retropharyngeal node should be examined carefully on sectional images.
