cysts of the oral region
TRANSCRIPT
Cysts of the oral region
Dr. Ahmed M. Adawy Professor Emeritus, Dep. Oral & Maxillofacial Surg.
Former Dean, Faculty of Dental MedicineAl-Azhar University
Cysts of the oral regionThe word cyst is derived from the Greek word Kystis meaning sac or bladder (1). By definition, a cyst is a “pouch” or sac without an opening, provided with a distinct membrane, and containing fluid or semifluid material, abnormally developed in one of the natural cavities or in the substance of an organ (2). Cysts of the oral region that are lined by epithelium are known as true cysts, while those not lined by epithelium are generally referred to as pseudo-cysts
Cysts of the oral region may be epithelial or non-epithelial, odontogenic or non-odontogenic, developmental, or inflammatory in origin. The distribution of jaw cysts according to diagnosis in a general population is: radicular cysts 56%, dentigerous cysts 17%, nasopalatine duct cysts 13%, odontogenic keratocyst 11%, globulomaxillary cysts 2.3%, traumatic bone cysts 1.0%, and eruption cysts 0.7% (3,4)
Cysts of the oral region
A revised histopathological classification of odontogenic tumors by the World Health Organization (WHO) has been published in 2005 (5), in which odontogenic keratocyst and calcifying odontogenic cyst were re-classified as tumors. Likewise, aneurysmal bone cyst and the solitary bone cyst have been described as ‘cavities’ rather than cysts (6). Cysts historically named globulomaxillary, median palatine and median mandibular cysts have been shown by numbers of studies as odontogenic or developmental cysts. This terminology is no longer used in diagnostic oral pathology departments in most parts of the world (4)
Cysts of the oral region
Cysts, especially epithelial cysts, are more commonly seen in jaw bones than other parts of the body. The higher incidence of cysts within the jaw bones is probably due to the abundant amount of epithelial remnants that can be left in the bones of the jaws during development. This "resting" epithelium is usually dormant or undergoes atrophy, but when stimulated, may form a cyst. Cysts that arise from tissues that would normally develop into teeth are referred to as odontogenic cysts. Other cysts of the jaws are termed non-odontogenic cysts. At least 90% of all jaw cysts are of odontogenic origin
Cysts of the oral region
Odontogenic cysts are group of lesions that originate from the tissues derived from tooth forming apparatus (7). They are slow growing and do not pose a significant management challenge, however, since they grow within the bones, they may cause bone or tooth resorption, bone expansion, fracture, or tooth displacement (8). They are divided into inflammatory and developmental
Odontogenic cysts
Radicular cystsRadicular cysts are the most common cystic lesions which affect the jaw. They arise from epithelial remnants which are stimulated to proliferate, by an inflammatory process which originates from pulpal necrosis of a non-vital tooth. They are most commonly found at the apices of the involved teeth. However, they may also be found on the lateral aspects of the roots in relation to lateral accessory root canals. They are symptomless and are diagnosed during routine radiologic investigations. Cortical expansion and root resorption of the affected tooth and displacement of the adjacent teeth are common features of radicular cysts
According to the literature, the most frequently affected site is the anterior maxilla (9). The higher prevalence of male sex in some studies may be explained by the fact that men usually have poorer oral hygiene habits and are more susceptible to trauma than women (8). Their prevalence is highest among patients in their third and fourth decades of life (9). Radiographically, the lesion is presented as well a defined round or oval radiolucent area surrounded by radiopaque margin. However, if the cyst is infected, it will have a hazy margin
Radicular cysts
Radicular cysts
Residual cystsResidual cysts are retained radicular cysts from teeth that have been extracted. The diagnosis of this pathology was more prevalent in patients over 50 years old (10). The finding that patients with residual cysts are older than patients with radicular cysts may be explained by the fact that cystic lesions are located inside the maxilla, cause no clinical symptoms after tooth extraction, and are only detected months or years later because of secondary infection or as an incidental radiographic finding
Residual cysts
Dentigerous cysts
Dentigerous cysts have been defined as those surrounding the crown of a tooth that has not migrated into the oral cavity, but still lies buried in the jaw bone (11). It has been reported that dentigerous cysts are the second most prevalent odontogenic cysts . The posterior region of the mandible is the most frequently affected site, followed by the anterior maxilla (10). Such prevalence may be explained by the large number of impacted mandibular third morals and maxillary canines. Most dentigerous cysts are found in patients in the second decade of life
Dentigerous cysts have the potential to resorb and expand into the surrounding tissue and displace bone and tooth roots causing malocclusion or facial asymmetry. Inferior alveolar nerve paresthesia caused by a dentigerous cyst have also been reported (12). However, in most of the cases this cyst is asymptomatic and diagnosed on routine dental radiographs usually appearing as a well defined radiolucency associated with the crown of an unerupted tooth
Dentigerous cysts
Dentigerous cyst
Nasopalatine duct cystAccording to the WHO classification, nasopalatine duct cyst is defined as a nonodontogenic, developmental, epithelial cyst of maxilla (13). Most of these cysts develop in the midline of anterior maxilla near the incisive foramen. It constitutes about 1.7–11.9% of all jaw cysts. Most cases occur in the fourth to sixth decade and men are affected three times more commonly than women. The lesion is believed to arise from epithelial remnants of the nasopalatine duct. These epithelial remnants either by spontaneous proliferation (idiopathic) or proliferation following trauma, or bacterial infections may become the source in giving rise to nasopalatine duct cyst
Most of these cysts are asymptomatic or cause minor symptoms such as swelling in relation to anterior palate near incisive papilla. Sometime cyst may be so destructive may perforate the labial and palatal bony palate. Tooth displacement is common finding (14). Differential diagnosis includes radicular cyst, and a wide incisive canal. A radicular cyst is usually associated with non-vital teeth, while, the nasopalatine cyst is usually associated with vital teeth. Radiographically, the lesions are well‑ circumscribed round, ovoid, or heart shaped radiolucencies located in between the roots of the maxillary central incisors
Nasopalatine duct cyst
Nasopalatine duct cyst
Diagnosis Aspiration with a 16 or 18 gauge needle is first done in all cases because some lesions of the same clinical and radiographic findings may well have been tumors and not cysts. Next, an incisional biopsy prior to definitive treatment is carried out to differentiate the “cyst” form other lesions having similar presentations , such as a keratocystic odontogenic tumor or unicystic ameloblastoma, but are more aggressive and necessitate more extensive treatment and the sacrificing of vital structures, bone, and teeth (15)
Aspiration
TreatmentThe treatment objective is restoring the morphology and function of the affected area. There are two basic surgical procedures, namely enucleation and marsupialization (decompression). The treatment of choice is dependent on the size and localization of the lesion, the bone integrity of the cystic wall, its proximity to vital structures and patient age (16). Enucleation means shelling out the entire cystic lesion without rupture. Marsupialization refers to creating a surgical window in the wall of the cyst, excavating the contents of the cyst and maintaining continuity between the cyst wall and the oral cavity. Only a portion of the cyst is removed with the remaining left in situ
EnucleationEnucleation is defined as a complete removal of the cystic lining with healing by primary intention. Enucleation with primary closure is the treatment of choice (17). It is a one stage surgical treatment followed by periodic radiographic examinations at regular intervals to observe the progress of bone regeneration of the defect. It also allows pathologic examination of the entire specimen. Enucleation can be done only when the jaw bone adjacent to the cyst is intact. This procedure is usually indicated for a small cyst, which can be done when the vital structures are not involved. If CT demonstrates erosions in the buccal or lingual cortices, marsupialization should be the treatment of choice
Enucleation with bone grafting is performed with large cystic lesions. Allogenic or xenogenic demineralized freeze-dried bone have been used for grafting with satisfactory results. Autogenous cancellous bone is considered the best grafting material and has been used with clinical success for treatment of cystic lesions for many years. However, donor site morbidity, is a factor to be considered. Its use for grafting of cystic lesions should be restricted if bone substitutes are available. Some grafting materials, however, are not always completely replaced by bone, and are encapsulated by connective tissue with maintaining of chronic inflammation, enhance bone resorption or partially rejected (18)
Enucleation
Enucleation
Dentigerous cyst
Six months post-enucleation
MarsupializationMarsupialization (Partsch’s operation), is the conversion of a cyst into a pouch (19). It is a relatively simple procedure, consists of surgically producing a window in the cystic wall to relieve intra-cystic tension. The technique promotes shrinkage of the cyst as well as bone fill. It is indicated when cyst is in close proximity to vital structures and where there is significant risk of injury with enucleation. The marsupialization concerns not only the radicular cysts, also follicular cysts can be treated by this technique in order to conserve and guide the eruption of permanent teeth. Three to six months later, enucleation is performed
The technique requires considerable aftercare and patient cooperation in keeping the cavity clean whilst it resolves and heals by relieving the internal pressure. The notable disadvantages of the marsupialization are: (a) it is a two-stage surgical procedure, (b) pathological tissue is left behind and a more sinister pathological process (i.e. squamous cell carcinoma) may be overlooked (20), and (c) in a large cystic cavity it takes a long period of time for the bone to regenerate
Marsupialization
Marsupialization
Marsupialization
Decompression
Decompression can be performed by making a small opening in the cyst and keeping it open with a drain (21). Decompression and secondary enucleation of cystic lesions constitute an alternative treatment for large cystic lesions of the jaws. This technique is especially appropriate for young patients, as there will be less damage to important structures like unerupted teeth. Decreased lesion size after decompression makes complete enucleation a safer and more predictable procedure
Numerous devices and adaptation methods were suggested and successfully used for maintaining the opening during decompression. The common materials used for making decompression devices are acrylic stents, nasopharyngeal airways, polyethylene tubes, nasal cannula, Luer syringes, and polyethylene intravenous tubes (22). These devices are secured by sutures or wiring fixation
Decompression
Decompression devices
1. Nair PN. New perspectives on radicular cysts: do they heal? Int Endod J; 31: 155, 1998.2. Archer WH. Oral and Maxillofacial Surgery, 5th ed. W.B. Saunders Com. pp 518, 1975. 3. Killy HC, Kay LW. An analysis of 471 benign cystic lesions of the jaws. Int Surg ;46: 540, 1966. 4. Shear M, Speight PM. Cysts of the oral and maxillofacial regions; 4th edition. Oxford: Blackwell Munksgaard; 2007. 5. Barnes L, Eveson JW, Reichart P, et al. World Health Organization Classification of Tumors. Pathology and Genetics of Head and Neck Tumors. Lyon: IARC Press; 2005.6, Reichart P, Philipsen H. Odontogenic tumors and allied lesions. New Malden: Quintessence Publishing: 2004.7. Jordan RCK, Speight PM. Current concepts of odontogenic tumours. Diagnostic Histopathology; 15: 303, 2009.8. Meningaud JP, Oprean N, Pitak-Arnnop P, et al. Odontogenic cysts: a clinical study of 695 cases. J Oral Sci; 48: 59,2006.
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9. Jones AV, Craig GT, Franklin CD. Range and demographics of odontogenic cysts diagnosed in a UK population over a 30-year period. J Oral Pathol Med; 35: 500, 2006. 10. Ochsenius G, Escobar E, Godoy L, et al. Odontogenic cysts: analysis of 2,944 cases in Chile. Med Oral Patol Oral Cir Bucal;12: E85, 2007. 11. Slootweg PJ. Lesions of the jaws. Histopathology;54:401, 2009. 12. Summer M, Bas B, Yildiz L. Inferior alveolar nerve paresthesiacaused by dentigerous cyst associated with three teeth. Med Oral Patol Oral Cir Bucal; 12:E388–E390, 2007.13. Francoli JE, Marques NA, Aytes LB, et al. Nasopalatine duct cyst: Report of 22 cases and review of literature. Med. Oral Patol. Oral Cir. Bucal; 2008, 13: 438, 2008.14. Basso ECB, Neto ER, Dib LL, et al. An unusual case of nasopalatine cyst in Brazilian population. Health Sci Inst; 30: 292, 2012. 15. Motamedi M H K: Periapical ameloblastoma: a case report. Br Dent J; 193: 443, 2002.
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16. Bodner L. Cystic lesions of the jaws in children. Int J Pediatr Otorhinolaryngol; 62: 25, 2002.17. van Doorm ME. Enucleation and primary closure of jaw cysts. Int J Oral Surg;1:17, 1972.18. Lalabonova K, Daskalo H. Jaw cysts and guided bone regeneration (a late complication after enucleation). J of IMAB; 4: 401, 2013.19. Sakkas N, Shoeen R. Obturator after marsupialization of a recurrence of a radicular cyst of the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol Endod; 103 : 16, 2007.20. Bodner L, Manor E, Shear M, et al. Primary in-traosseous squamous cell carcinoma arising in an odontogenic cyst- A clinicopathologic analysis of 116 reported cases. J Oral Pathol Med; 40: 733, 2011. 21. Pogrel MA. Treatment of keratocysts: The case for decompression and marsupialization. J Oral Maxillofac Surg; 23: 1667, 2005. 22. Costa FW, Carvalho FS, Chaves FN, et al. A suitable device for cystic lesions close to the tooth-bearing areas of the jaws. J Oral Maxillofac Surg; 72: 96, 2014.
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