Recurrences of oral cancer due to discontinuous periosteal involvement.

In order to determine whether an in-transit metastasis on the lingual periosteum might be a cause for recurrences of oral cancer, a retrospective review of 576 surgically treated patients was undertaken. In two patients, a simultaneous discontinuous involvement of the periosteum was verified. In 91 patients, a local recurrence was found, and, in 19, it was explained by periosteal involvement. In these patients, the recurrent tumor was distinct in appearance: a submucosal mass attached to the lingual aspect of the mandible with or without a submandibular fistula. Osteolysis was visible on radiographs in some cases, although it was a late sign. The recurrences on the periosteum appeared later (11.9 months) than other recurrences (8.2 months). Almost half of tongue cancer recurrences (9 of 22) were due to periosteal involvement; this type of recurrence was less frequent at other sites. The presumed lymphatic pathway was confirmed by the results of perlingual lymphography, with the contrast material reaching the lingual aspect of the mandible after 60% of the injections. Both the clinical and experimental results of this study suggest that a pathway exists for discontinuous periosteal involvement from lower oral cavity cancer.