Clinical diagnosis

Case 82

4.Maxillary torus (Torus palatinus)

【Progress】
 One month later she received surgical resection of bony protrusion of Torus palatinus by oral cavity surgeons.

【Discussion】
 Torus palatinus arises from the midline of the hard plate. It usually forms hard bony protrusion with lobulated margin (1, 2). Torus which means protuberance is termed from Latin language. There are two tori growing out in oral cavity: maxillary torus (Torus palatinus) and mandibular torus (1-3). Maxillary torus predominantly occurs in female, while mandibular torus predominantly occurs in male (3). There is a tendency of torus palatinus occurring in females 2:1 (1-3). Our patient was a middle-aged woman. Histological examination indicates excessive proliferation (overgrowth: exostosis or hyperostosis) of bone tissue including bone marrow and fibrotic component (4-6). It is covered with a thin and poorly vascularized mucosa (6, 7). Oral CT in our case showed the inside of her torus was similar as that of maxillary bone itself, implying the overgrowth of bone tissue.
 Tori appear in the early adults and as growing older, it shrinks because of the re-absorption of bones (6). The pathogenesis is uncertain but related to be genetic: autosomal dominant inheritance, indicating parents with torus palantinus have a fifty percent chance of passing the gene to their children (1-5).
 Torus palatinus is reported to be more common in Mongolian. Its incidence in the age range of 45 to 50 is 24 % (1-5). Tori are usually asymptomatic in most patients but can occur ulcerations due to poorly vascularized mucosa. Tori are also more common in the patients who underwent hemodialysis with hyper para-thyroidism (5-7). Meanwhile, it is reported that bisphosphonate which are usually used to treat for osteoporosis, multiple myeloma, bone metastases of the breast and prostate cancer, might cause osteonecrosis of torus palatinus (6, 7). The mechanism of bisphosphonate causing osteonecrosis of tori is, however, not clarified.
 Biopsies are not necessary and imaging studies are useful in case of surgical resection to detect the extent and to exclude other disease (8). Most cases can leave them without treatments but they could require surgical resection if they interfered with the placement of the dentures or if they interfered with speech and/or chewing (1-5). In our case, she suffered from chewing food and received oral CT in advance of surgical resection

【Summary】
 We present a sixty three-year-old woman who had a maxillary torus, interfering with chewing. In advance receiving surgical resection, CT showed a 3cm lobulated bony mass composed of three parts, extending from midline of the hard plate into oral cavity. The inside of the torus seemed to be similar as the surrounding maxillary bone itself,implying the overgrowing of the maxillary bone. We should keep in mind that there exists maxillary torus and mandibular torus whose are overgrowth of bone tissue. Maxillary torus predominantly occurs in female, while mandibular torus predominantly occurs in male. Torus might progress the growth in the patients with renal dialysis and bisphosphonate might cause torus necrosis.

【References】
1.Loukas M, et al. The tori of the mouth and ear: a review. Clin Anat 2013;26:953–60. [PubMed]
2.Pazianas M, et al. A review of the literature on osteonecrosis of the jaw in patients with osteoporosis treated with oral bisphosphonates: prevalence, risk factors, and clinical characteristics. Clin Ther. 2007;29:1548–1558.
3.García-García AS, et al. Current status of the torus palatinus and torus mandibularis. Med Oral Patol Oral Cir Bucal. 2010;15:e353–e360. [PubMed]
4.Sinisterra G, et al. Spontaneous exposure of a torus palatine midline. Biomedical. 2013;33:31-5.
5.Garcia-Garcia AS, et al. Current status of the torus and torus mandibularis palatinus. Oral Med Oral Pathol Oral Cir. 2010;15:e353-60.
6.Goldman ML et al. A novel case of bisphosphonate-related osteonecrosis of the torus palatinus in a patient with metastatic breast cancer. Oncology. 2006;71:306–398.
7.Godinho M, et al. Torus Palatinus Osteonecrosis Related to Bisphosphonate: A Case Report. Case Rep Dermatol. 2013 Jan-Apr; 5(1): 120–125. Published online 2013 Apr 20. doi: 10.1159/000350674 PMCID: PMC3656696
8.Yonetsu K, Nakamura T. CT of calcifying jaw bone diseases. AJR 2001;177(4):937-943.

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2017.11.29