POSSIBLE ROUTES OF SPREAD OF CARCINOMA OF THE MAXILLARY SINUS TO THE ORAL CAVITY

Carcinomas arising in the maxillary sinus, occasionally present clinic ally in the oral cavity alone the occlusal ridge of the upper alveolus . The mechanism of this spread has not been investigated but it may re semble invasion of the mandible by oral carcinomas, which tend to inva de the soft tissues rather than eroding through bone. In Britain, such patients are usually edentulous. This project examines deficiencies i n the bony walls of the maxillary sinus to determine possible routes o f spread. Maxillae were obtained from one side of 17 dissecting room c adavers, aged 71-95 years; 15 were edentulous. The roof of the maxilla ry sinus was removed in all specimens. Five maxillae were each cut int o six slices, 0.5 cm thick, in a vertical bucco-lingual plane. In all, soft tissues were removed by treatment in dilute bleach. Histological sections, cut in the horizontal plane, were prepared of a further thr ee maxillae. Several possible routes were identified by which tumors c ould spread from the sinus to the oral cavity: 1) directly through for amina in its floor; 2) through numerous foramina in its Boor to the ma rrow cavity of the alveolar process, which mostly contained fat amongs t narrow bony trabeculae. (The marrow cavity, in turn, had numerous co mmunications with the occlusal surface); 3) through foramina which car ried branches of the superior alveolar nerves and vessels: 4) through deficiencies in the bony walls of the sinus at the neurovascular groov es and elsewhere. (C) 1998 Wiley-Liss, Inc.