Torus palatinus . Report of two cases

Hyperostosis is defined as a benign neoformation of bone tissue, diffused or localized hypertrophy thereof. In the oral cavity can affect the lingual surface of the mandibular bone (torus mandibularis), the hard palate (torus palatinus) or presented as multiple exostosis [1]. The latin word torus means tumor or circular protrusion and is not considered as a pathological condition, but an anatomical variation. The term torus is introduced by Kupfer and Besselhagen in 1879, and is used to designate the exostosis arising on the midline of the palate and the back and inside of the jaw [2].


INTRODUCTION
Hyperostosis is defined as a benign neoformation of bone tissue, diffused or localized hypertrophy thereof.In the oral cavity can affect the lingual surface of the mandibular bone (torus mandibularis), the hard palate (torus palatinus) or presented as multiple exostosis [1].The latin word torus means tumor or circular protrusion and is not considered as a pathological condition, but an anatomical variation.The term torus is introduced by Kupfer and Besselhagen in 1879, and is used to designate the exostosis arising on the midline of the palate and the back and inside of the jaw [2].These bony growths are usually found in adults and occur after puberty.There is a predilection for females 2:1, in the palatal torus; as reported by several studies mandibular torus occurs most often in men [2,3].It is estimated that 20-25% of the population, including Asian, Native American Indians and Eskimos have some torus, which are more common in women than men.According to the Institute of Reference of Oral Pathology, University of Chile, the frequency of torus in white Americans is 25%, 19% in black Americans and in Chile the prevalence corresponds to 37% [2].
The prevalence is between 6 and 8% in the United States and reaches 25% in other populations worldwide [1][2][3], while the incidence of mandibular torus is estimated below 8% [2,4].Tori are more prevalent between 11 and 30 years old and very rare appearance before the age of 10.According to Eggen and Natvug, it is more frequent between 10 and 49 years old, and rare appearance after 50 [1][2][3].
Regarding its pathogenesis genetically originated are believed in large measure, but local factors micro stress and trauma can be contributory [3,5,6].According to a research study conducted by Morrison MD and F. Tamimi, published in 2013, there was a statistically significant association between the presence of temporomandibular joint dysfunction, or the presence of dental wear, hypertension and predisposition to develop palatinus torus [5,6] Pei-Jung Chao and colleagues [7], by a study conducted in 2013 among 119 hemodialysis patients and published in 2015, ruled the relationship between hyperparathyroidism raised as a cause of development of oral torus in chronic hemodialysis patients.
Clinically [1,2], manifest as compact prominences covered with healthy looking mucosa, they are usually asymptomatic, especially less than 1.5 cm; They are characterized by a well defined, unilateral or bilateral slow, benign, circumscribed bone growth.The torus can me located only under masticatory; ulcer resulting from trauma can take weeks to months to heal because the underlying bone tissue is poorly vascularized.They can be confined to the anterior or posterior part of the palate and in some cases may be spreaded throughout the midline from the pit prior to completion cleft of the hard palate.These abnormalities are usually symmetrical.According to their shape, palatal tori are divided into levels, unilobulados, multilobed, nodular, irregular or fusiform; the latter are the most common.
In histopathology [1][2][3]: the torus is characterized by dense bone outgrowth of a laminated pattern and small spaces occupied by thick bone marrow or scattered fibrovascular stroma, where you can observe minimum osteoblastic or occasional periosteal activity activity.
Tori require treatment when they are large, alter the phonatory function, generate dental displacement or produce trauma and ulceration of the mucosal surface, when they interfere with hygiene and are the cause of halitosis, but especially when preclude the placement and use of total or dentures.When treatment is indicated, the lesions can be cut or removed surgically, cutting from its base binding [1][2][3].

CASE REPORTS Case 1
77 years old white female, housewife, from an urban area of Paraguay, hospitalized for communityacquired pneumonia, evaluated by dermatology by a raised lesion about 6-8 years of evolution, which gradually increased in size without accompanying symptoms.Tobacco, alcohol and other underlying pathologies refuses.Using of dental prosthesis smoothly.Family history is negative.Physical exam: unilobulated tumor of about 1 cm, net limits and regular edges, bright erythematous, smooth, solid stone consistency that is located on midline of hard palate (Fig. 1).Punch biopsy was taken for histopathology.

Case 2
30 years old white and healthy female, , from an urban area of Paraguay, with no personal or family history of pathological value evaluated in a routine examination of a raised lesion found on the hard palate; it is present since adolescence and is asymptomatic.Physical exam: oval tumor, unilobular, 1.5 x 1 cm in diameters, net limits, regular edges, covered by bright erythematous mucosa, of solid consistency, smooth surface, located on hard palate (Fig. 2).Punch biopsy was taken for histopathology.

Histopathology
At the base of the biopsy mature trabecular bone with osteoblastic rim, with osteocytes in lacunae covered by a cartilage cap formation.The intertrabecular space has vascular connective stroma, with no bone marrow (Fig. 3).

Management
Patients were evaluated by dentistry and maxillofacial surgery, and because they do not have symptoms, periodical controls were indicated.

Figure 2 :
Figure 2: Clinical case 2. In both cases oval unilobular tumor, 1.5 cm in its great dimension, net limits, regular edges, covered by bright erythematous mucosa, of solid consistency, smooth surface, resting on hard palate.

Figure 3 :
Figure 3: Histopathology.Mature trabecular bone with osteoblastic rim at the base of the biopsy (HE4X left), with osteocytes in lacunae covered by a cartilaginous cap formation.The intertrabecular space has vascular connective stroma, with no bone marrow (HE 40X right).