YIJOM-3125; No of Pages 4
Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2015.03.008, available online at http://www.sciencedirect.com
Clinical Paper A Personal View
The keratocystic odontogenic tumour (KCOT)—an odyssey
M. A. Pogrel Oral and Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
M.A. Pogrel: The keratocystic odontogenic tumour (KCOT)—an odyssey. Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx. # 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Abstract. The most appropriate management for the lesion now known as the keratocystic odontogenic tumour (previously known as the odontogenic keratocyst) remains controversial. This article reviews the different management protocols adopted by one surgical unit over the last 30 years and the results obtained from the different treatment modalities. A current treatment protocol consisting of initial decompression followed by aggressive curettage and peripheral ostectomy with methylene blue staining appears to be successful, but our longest follow-up is only 6 years.
The lesion now called the keratocystic odontogenic tumour (KCOT) was first described by Philipsen in 19561 under the name odontogenic keratocyst. This original article was in Danish but had a summary in English. It was, however, not widely recognized as a separate entity until the articles by Browne in 1970 and 1971,2,3 which clearly delineated the clinical and histological features of the lesion, coupled with its high recurrence rate with simple enucleation. Prior to this time, it is felt that most of these lesions were identified as primordial cysts, which is a term no longer used. Following the confirmation of the accuracy of histological diagnosis and of the high recurrence rate of these lesions with simple treatment, there was a division of philosophies on their management. These varied from the feeling of my old chief, Gordon Hardman from North Wales, who essentially stated that ‘we always knew there were some cysts that recurred, even 0901-5027/000001+04
though we did not have a special name for them, and all we did was curette them out every 5–10 years. Why shouldn’t we just continue to do that?’ all the way to the opinion of people like Paul Bramley4 who recommended much more aggressive treatment, consisting of either ‘en-bloc’ or segmental resection, depending on the size. With these two diametrically opposing views, an effort was made to identify a middle course that might result in an acceptable success rate in the long term, with an acceptably low morbidity. Paul Stoelinga and others are of the opinion that these lesions can arise from downgrowth from the oral epithelium and that therefore the overlying oral epithelium should be excised along with the lesion.5 Since these lesions normally occur in the posterior mandible, this can involve incisions over on the lingual side of the crest of the ridge, so care has to be taken to identify and protect the lingual nerve, if appropriate.
Key words: keratocystic odontogenic tumour; odontogenic keratocyst; treatment protocols. Accepted for publication 10 March 2015
In an effort to identify this middle course, treatment has consisted of techniques ranging from enucleation plus cryosurgery – a technique learned from one of my mentors, Paul Bradley,6,7 and utilized extensively over the last 30 years8,9 – to enucleation plus Carnoy’s solution,10,11 enucleation with peripheral ostectomy,12 and more recently marsupialization and decompression,13–16 with various combinations. We first published an article on the use of enucleation coupled with liquid nitrogen in 19938 and at that time reported a recurrence rate of around 11.5%, which was less than the recurrence rates of 20–60% that were being reported for simple enucleation. With the extended followup of these patients for a longer period (up to 25 years now), it does appear that the recurrence rate has remained around 10%. The problem with the technique, however, has been access to the equipment, which is being used less and less
# 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
2
Pogrel
in other medical specialties, so hospitals often do not have access to it. Also, if one is not meticulous in protecting the soft tissues, there will be necrosis of the soft tissues leading to wound breakdown and a prolonged recovery, and at least partial loss of any bone graft that has been used. At that time we were recommending bone grafting of any lesion over 4 cm in size,17 but ultimately reduced this to 3 cm in size in order to accelerate the healing of smaller lesions. Around 1995, following the final retirement of my mentor, Gordon Hardman, in North Wales, I spent some time sorting out his slide collection which consisted of many thousands of 35-mm Kodachrome slides. In this I found a number of cases of cysts that he had obviously marsupialized and decompressed in the early 1950s or possibly even earlier. From examining these slides, it did appear to be a practical technique, which had been largely forgotten following the widespread use of enucleation and primary closure, coupled with the liberal use of antibiotics. It was therefore decided to apply this as a definitive technique for the management of odontogenic keratocysts, and we
Fig. 1. A drainage tube made from a paediatric feeding tube and wired around the first molar. The tube is going into a large cyst of the left mandibular angle area, and the tube ends opposite the first bicuspid tooth making it easier for the patient to irrigate.
published our first results in 2004. These seemed to show very satisfactory outcomes for a relatively small number of patients,14 with a recurrence rate around 5%. However, during the follow-up of these patients, we started to see more recurrences, and in 2007 I published a partial retraction stating a recurrence rate of around 12% over a relatively short period of time.16 Since that time, the number of patients that we have treated
with this technique has risen to 73, and the recurrence rate at the present time has risen to 27% (20 recurrences). The longer we follow these patients, the more recurrences we seem to see, and one can only speculate what the final recurrence rate may be when these patients have been followed up for 20 years or longer. Once we realized that the recurrence rate was going to be as high as it had turned out to be, we looked around for an
Fig. 2. Radiograph showing a large keratocystic odontogenic tumour extending from the lower left first molar over to the lower right first molar region (A). This was drained from two separate sites (the drainage tubes can be seen on the radiograph), resulting in almost complete resolution of the lesion (B).
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
The keratocystic odontogenic tumour alternative technique that would combine the best of these techniques. In 2006, we introduced the technique whereby we decompressed the lesions until they appeared radiographically to have resolved down to about 2–3 cm in size, and we then surgically enucleated the lesions and carried out a peripheral ostectomy to remove any cyst remnants that might be in the surrounding bone. The advantages of this technique are outlined below. The lesions do decompress very satisfactorily. By this time we had modified the technique to utilize a 14 French gauge paediatric feeding tube as the decompression tube and to wire it around the adjacent first molar tooth, passing the wire through the wall of the tube so as not to compress it. We could then bring the drainage tube forward to the bicuspid region where patients found it easy to irrigate (Fig. 1). This meant that patients could keep the area clean and irrigate it more easily. If the lesion was anywhere else except the posterior mandible, the technique was modified accordingly. For extremely large lesions that crossed the midline, a drainage tube could be placed on each side (Fig. 2). Patients are followed radiographically at 3-month intervals. The drains can be
shortened as appropriate, and the radiographic shrinkage of the lesion noted. When the lesion is approximately 2– 3 cm in size, the decision can be made to surgically enucleate the remaining cyst. At this stage, it was noted that the cyst lining had become thicker and easier to enucleate than with the original KCOT. This has been noted before, that there is a change in the histological nature of the cyst lining in that it does become thicker, more robust, and more like oral epithelium.14,18 It was, however, felt that additional treatment was required to remove any small daughter cysts or remnants beyond the visible cyst lining. By this time, Carnoy’s solution had become virtually unobtainable in California, as the California Occupational Health and Safety Administration (CalOSHA) had classified the chloroform in it as a carcinogen, and the handling of glacial acetic acid requires a high volume fume cupboard. Some practitioners have been removing the chloroform from the Carnoy’s solution, but this new formulation has not been tested and has not been shown to be effective. We could have gone back to using liquid nitrogen cryosurgery, but the problems
3
with this have already been mentioned. In view of the issues with liquid nitrogen, we elected to use a technique of peripheral ostectomy. For this, the cyst is first enucleated, and then the bony margins are painted with methylene blue using a Q-tip. Once the walls are completely stained, the cavity is irrigated and then all the remaining bluestaining bone is removed with a pineappletype bur; the residual cavity is then thoroughly irrigated. It does appear that the methylene blue stains to a depth of about 0.5 mm in cortical bone and 1–1.5 mm in cancellous bone, so if the remaining cells are within this area, they should be removed (Fig. 3). In the meantime, in 2006 the World Health Organization reclassified this lesion from an odontogenic cyst to a benign odontogenic tumour and renamed it the keratocystic odontogenic tumour (KCOT).19,20 Initially the odontogenic keratocyst existed in two forms, a parakeratinized form and an orthokeratinized form. The term ‘keratocystic odontogenic tumour’ only refers to the parakeratinized form of this lesion, whilst the orthokeratinized form continues to be classified as a benign odontogenic cyst and does not appear to have the same recurrence potential. To date, we have treated some 29 lesions utilizing this modified technique of decompression, enucleation, and peripheral ostectomy. Our follow-up period varies, with six of these patients now followed for longer than 5 years and the shortest only followed for 4 months. To date, we have not seen any recurrences, but time will tell whether this proves to be a superior technique to any of the other techniques described. If it does stand the test of time, it will represent a reasonable middle course between enucleation and resection for the lesion now known as the keratocystic odontogenic tumour. Funding
None. Competing interests
None declared. Ethical approval
Not required. Patient consent Fig. 3. The technique of peripheral ostectomy. (A) The area is opened up, the overlying mucosa is excised, and the cyst is enucleated. (B) The bony margins are painted with methylene blue on a Q-tip, and then all the blue-stained bone is removed with a pineapple bur taking care to avoid trauma to the inferior alveolar nerve.
All our patients sign a consent to be photographed and for the images to be used for academic purposes.
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
4
Pogrel
References 1. Philipsen HP. Om keratocyster (kolesteatomer) i kæberne. Tandlægebladet 1956;60:963–81. 2. Browne RM. The odontogenic keratocyst. Clinical aspects. Br Dent J 1970;128:225–31. 3. Browne RM. The odontogenic keratocyst Histological features and their correlation with clinical behaviour. Br Dent J 1971;131: 249–59. 4. Bramley P, The odontogenic keratocyst—an approach to treatment. Int J Oral Surg 1974;3: 337–41. 5. Stoelinga PJ. Excision of the overlying, attached mucosa, in conjunction with cyst enucleation and treatment of the bony defect with Carnoy solution. Oral Maxillofac Surg Clin North Am 2003;15:407–14. 6. Bradley PF, Fisher AD. The cryosurgery of bone. An experimental and clinical assessment. Br J Oral Surg 1975;13:111–27. 7. Bradley PF. Modern trends in cryosurgery of bone in the maxillo-facial region. Int J Oral Surg 1978;7:405–15. 8. Pogrel MA. The use of liquid nitrogen cryotherapy in the management of locally aggressive bone lesions. J Oral Maxillofac Surg 1993;51:269–73. 9. Schmidt BL, Pogrel MA. The use of enucleation and liquid nitrogen cryotherapy in the
10.
11.
12.
13.
14.
15.
16.
17.
management of odontogenic keratocysts. J Oral Maxillofac Surg 2001;59:720–5. Stoelinga PJ. Long-term follow-up on keratocysts treated according to a defined protocol. Int J Oral Maxillofac Surg 2001;30:14–25. Voorsmit RA, Stoelinga PJ, van Haelst UJ. The management of keratocysts. J Maxillofac Surg 1981;9:228–36. Irvine GH, Bowerman JE. Mandibular keratocysts: surgical management. Br J Oral Maxillofac Surg 1985;23:204–9. Pogrel MA. Decompression and marsupialization as a treatment for the odontogenic keratocyst. Oral Maxillofac Surg Clin North Am 2003;15:415–27. Pogrel MA, Jordan RC. Marsupialization as a definitive treatment for the odontogenic keratocyst. J Oral Maxillofac Surg 2004;62: 651–5. Pogrel MA. Treatment of keratocysts: the case for decompression and marsupialization. J Oral Maxillofac Surg 2005;63:1667–73. Pogrel MA. Decompression and marsupialization as definitive treatment for keratocysts— a partial retraction. J Oral Maxillofac Surg 2007;65:362–3. Salmassy DA, Pogrel MA. Liquid nitrogen cryosurgery and immediate bone grafting in the management of aggressive primary jaw
lesions. J Oral Maxillofac Surg 1995;53: 784–90. 18. August M, Faquin WC, Troulis MJ, Kaban LB. Dedifferentiation of odontogenic keratocyst epithelium after cyst decompression. J Oral Maxillofac Surg 2003;61:678–83. 19. Philipsen HP. Keratocystic odontogenic tumour. In: Barnes L, Eveson JW, Reichart P, Sidransky D, editors. World Health Organization Classification of Tumours. Pathology and genetics: head and neck tumours. Lyon: IARC Press; 2005. p. 306–7. 20. Reichart PA, Philipsen HP, Sciubba JJ. The new classification of head and neck tumours (WHO)—any changes? Oral Oncol 2006;42: 757–8.
Address: M. Anthony Pogrel Oral and Maxillofacial Surgery University of California San Francisco Room C522 Box 0440 521 Parnassus Avenue San Francisco CA 94143-0440 USA Tel: +1 415 476 8225; Fax: +1 415 476 6305 E-mail: [email protected]
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2015.03.008, available online at http://www.sciencedirect.com
Clinical Paper A Personal View
The keratocystic odontogenic tumour (KCOT)—an odyssey
M. A. Pogrel Oral and Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
M.A. Pogrel: The keratocystic odontogenic tumour (KCOT)—an odyssey. Int. J. Oral Maxillofac. Surg. 2015; xxx: xxx–xxx. # 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Abstract. The most appropriate management for the lesion now known as the keratocystic odontogenic tumour (previously known as the odontogenic keratocyst) remains controversial. This article reviews the different management protocols adopted by one surgical unit over the last 30 years and the results obtained from the different treatment modalities. A current treatment protocol consisting of initial decompression followed by aggressive curettage and peripheral ostectomy with methylene blue staining appears to be successful, but our longest follow-up is only 6 years.
The lesion now called the keratocystic odontogenic tumour (KCOT) was first described by Philipsen in 19561 under the name odontogenic keratocyst. This original article was in Danish but had a summary in English. It was, however, not widely recognized as a separate entity until the articles by Browne in 1970 and 1971,2,3 which clearly delineated the clinical and histological features of the lesion, coupled with its high recurrence rate with simple enucleation. Prior to this time, it is felt that most of these lesions were identified as primordial cysts, which is a term no longer used. Following the confirmation of the accuracy of histological diagnosis and of the high recurrence rate of these lesions with simple treatment, there was a division of philosophies on their management. These varied from the feeling of my old chief, Gordon Hardman from North Wales, who essentially stated that ‘we always knew there were some cysts that recurred, even 0901-5027/000001+04
though we did not have a special name for them, and all we did was curette them out every 5–10 years. Why shouldn’t we just continue to do that?’ all the way to the opinion of people like Paul Bramley4 who recommended much more aggressive treatment, consisting of either ‘en-bloc’ or segmental resection, depending on the size. With these two diametrically opposing views, an effort was made to identify a middle course that might result in an acceptable success rate in the long term, with an acceptably low morbidity. Paul Stoelinga and others are of the opinion that these lesions can arise from downgrowth from the oral epithelium and that therefore the overlying oral epithelium should be excised along with the lesion.5 Since these lesions normally occur in the posterior mandible, this can involve incisions over on the lingual side of the crest of the ridge, so care has to be taken to identify and protect the lingual nerve, if appropriate.
Key words: keratocystic odontogenic tumour; odontogenic keratocyst; treatment protocols. Accepted for publication 10 March 2015
In an effort to identify this middle course, treatment has consisted of techniques ranging from enucleation plus cryosurgery – a technique learned from one of my mentors, Paul Bradley,6,7 and utilized extensively over the last 30 years8,9 – to enucleation plus Carnoy’s solution,10,11 enucleation with peripheral ostectomy,12 and more recently marsupialization and decompression,13–16 with various combinations. We first published an article on the use of enucleation coupled with liquid nitrogen in 19938 and at that time reported a recurrence rate of around 11.5%, which was less than the recurrence rates of 20–60% that were being reported for simple enucleation. With the extended followup of these patients for a longer period (up to 25 years now), it does appear that the recurrence rate has remained around 10%. The problem with the technique, however, has been access to the equipment, which is being used less and less
# 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
2
Pogrel
in other medical specialties, so hospitals often do not have access to it. Also, if one is not meticulous in protecting the soft tissues, there will be necrosis of the soft tissues leading to wound breakdown and a prolonged recovery, and at least partial loss of any bone graft that has been used. At that time we were recommending bone grafting of any lesion over 4 cm in size,17 but ultimately reduced this to 3 cm in size in order to accelerate the healing of smaller lesions. Around 1995, following the final retirement of my mentor, Gordon Hardman, in North Wales, I spent some time sorting out his slide collection which consisted of many thousands of 35-mm Kodachrome slides. In this I found a number of cases of cysts that he had obviously marsupialized and decompressed in the early 1950s or possibly even earlier. From examining these slides, it did appear to be a practical technique, which had been largely forgotten following the widespread use of enucleation and primary closure, coupled with the liberal use of antibiotics. It was therefore decided to apply this as a definitive technique for the management of odontogenic keratocysts, and we
Fig. 1. A drainage tube made from a paediatric feeding tube and wired around the first molar. The tube is going into a large cyst of the left mandibular angle area, and the tube ends opposite the first bicuspid tooth making it easier for the patient to irrigate.
published our first results in 2004. These seemed to show very satisfactory outcomes for a relatively small number of patients,14 with a recurrence rate around 5%. However, during the follow-up of these patients, we started to see more recurrences, and in 2007 I published a partial retraction stating a recurrence rate of around 12% over a relatively short period of time.16 Since that time, the number of patients that we have treated
with this technique has risen to 73, and the recurrence rate at the present time has risen to 27% (20 recurrences). The longer we follow these patients, the more recurrences we seem to see, and one can only speculate what the final recurrence rate may be when these patients have been followed up for 20 years or longer. Once we realized that the recurrence rate was going to be as high as it had turned out to be, we looked around for an
Fig. 2. Radiograph showing a large keratocystic odontogenic tumour extending from the lower left first molar over to the lower right first molar region (A). This was drained from two separate sites (the drainage tubes can be seen on the radiograph), resulting in almost complete resolution of the lesion (B).
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
The keratocystic odontogenic tumour alternative technique that would combine the best of these techniques. In 2006, we introduced the technique whereby we decompressed the lesions until they appeared radiographically to have resolved down to about 2–3 cm in size, and we then surgically enucleated the lesions and carried out a peripheral ostectomy to remove any cyst remnants that might be in the surrounding bone. The advantages of this technique are outlined below. The lesions do decompress very satisfactorily. By this time we had modified the technique to utilize a 14 French gauge paediatric feeding tube as the decompression tube and to wire it around the adjacent first molar tooth, passing the wire through the wall of the tube so as not to compress it. We could then bring the drainage tube forward to the bicuspid region where patients found it easy to irrigate (Fig. 1). This meant that patients could keep the area clean and irrigate it more easily. If the lesion was anywhere else except the posterior mandible, the technique was modified accordingly. For extremely large lesions that crossed the midline, a drainage tube could be placed on each side (Fig. 2). Patients are followed radiographically at 3-month intervals. The drains can be
shortened as appropriate, and the radiographic shrinkage of the lesion noted. When the lesion is approximately 2– 3 cm in size, the decision can be made to surgically enucleate the remaining cyst. At this stage, it was noted that the cyst lining had become thicker and easier to enucleate than with the original KCOT. This has been noted before, that there is a change in the histological nature of the cyst lining in that it does become thicker, more robust, and more like oral epithelium.14,18 It was, however, felt that additional treatment was required to remove any small daughter cysts or remnants beyond the visible cyst lining. By this time, Carnoy’s solution had become virtually unobtainable in California, as the California Occupational Health and Safety Administration (CalOSHA) had classified the chloroform in it as a carcinogen, and the handling of glacial acetic acid requires a high volume fume cupboard. Some practitioners have been removing the chloroform from the Carnoy’s solution, but this new formulation has not been tested and has not been shown to be effective. We could have gone back to using liquid nitrogen cryosurgery, but the problems
3
with this have already been mentioned. In view of the issues with liquid nitrogen, we elected to use a technique of peripheral ostectomy. For this, the cyst is first enucleated, and then the bony margins are painted with methylene blue using a Q-tip. Once the walls are completely stained, the cavity is irrigated and then all the remaining bluestaining bone is removed with a pineappletype bur; the residual cavity is then thoroughly irrigated. It does appear that the methylene blue stains to a depth of about 0.5 mm in cortical bone and 1–1.5 mm in cancellous bone, so if the remaining cells are within this area, they should be removed (Fig. 3). In the meantime, in 2006 the World Health Organization reclassified this lesion from an odontogenic cyst to a benign odontogenic tumour and renamed it the keratocystic odontogenic tumour (KCOT).19,20 Initially the odontogenic keratocyst existed in two forms, a parakeratinized form and an orthokeratinized form. The term ‘keratocystic odontogenic tumour’ only refers to the parakeratinized form of this lesion, whilst the orthokeratinized form continues to be classified as a benign odontogenic cyst and does not appear to have the same recurrence potential. To date, we have treated some 29 lesions utilizing this modified technique of decompression, enucleation, and peripheral ostectomy. Our follow-up period varies, with six of these patients now followed for longer than 5 years and the shortest only followed for 4 months. To date, we have not seen any recurrences, but time will tell whether this proves to be a superior technique to any of the other techniques described. If it does stand the test of time, it will represent a reasonable middle course between enucleation and resection for the lesion now known as the keratocystic odontogenic tumour. Funding
None. Competing interests
None declared. Ethical approval
Not required. Patient consent Fig. 3. The technique of peripheral ostectomy. (A) The area is opened up, the overlying mucosa is excised, and the cyst is enucleated. (B) The bony margins are painted with methylene blue on a Q-tip, and then all the blue-stained bone is removed with a pineapple bur taking care to avoid trauma to the inferior alveolar nerve.
All our patients sign a consent to be photographed and for the images to be used for academic purposes.
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
YIJOM-3125; No of Pages 4
4
Pogrel
References 1. Philipsen HP. Om keratocyster (kolesteatomer) i kæberne. Tandlægebladet 1956;60:963–81. 2. Browne RM. The odontogenic keratocyst. Clinical aspects. Br Dent J 1970;128:225–31. 3. Browne RM. The odontogenic keratocyst Histological features and their correlation with clinical behaviour. Br Dent J 1971;131: 249–59. 4. Bramley P, The odontogenic keratocyst—an approach to treatment. Int J Oral Surg 1974;3: 337–41. 5. Stoelinga PJ. Excision of the overlying, attached mucosa, in conjunction with cyst enucleation and treatment of the bony defect with Carnoy solution. Oral Maxillofac Surg Clin North Am 2003;15:407–14. 6. Bradley PF, Fisher AD. The cryosurgery of bone. An experimental and clinical assessment. Br J Oral Surg 1975;13:111–27. 7. Bradley PF. Modern trends in cryosurgery of bone in the maxillo-facial region. Int J Oral Surg 1978;7:405–15. 8. Pogrel MA. The use of liquid nitrogen cryotherapy in the management of locally aggressive bone lesions. J Oral Maxillofac Surg 1993;51:269–73. 9. Schmidt BL, Pogrel MA. The use of enucleation and liquid nitrogen cryotherapy in the
10.
11.
12.
13.
14.
15.
16.
17.
management of odontogenic keratocysts. J Oral Maxillofac Surg 2001;59:720–5. Stoelinga PJ. Long-term follow-up on keratocysts treated according to a defined protocol. Int J Oral Maxillofac Surg 2001;30:14–25. Voorsmit RA, Stoelinga PJ, van Haelst UJ. The management of keratocysts. J Maxillofac Surg 1981;9:228–36. Irvine GH, Bowerman JE. Mandibular keratocysts: surgical management. Br J Oral Maxillofac Surg 1985;23:204–9. Pogrel MA. Decompression and marsupialization as a treatment for the odontogenic keratocyst. Oral Maxillofac Surg Clin North Am 2003;15:415–27. Pogrel MA, Jordan RC. Marsupialization as a definitive treatment for the odontogenic keratocyst. J Oral Maxillofac Surg 2004;62: 651–5. Pogrel MA. Treatment of keratocysts: the case for decompression and marsupialization. J Oral Maxillofac Surg 2005;63:1667–73. Pogrel MA. Decompression and marsupialization as definitive treatment for keratocysts— a partial retraction. J Oral Maxillofac Surg 2007;65:362–3. Salmassy DA, Pogrel MA. Liquid nitrogen cryosurgery and immediate bone grafting in the management of aggressive primary jaw
lesions. J Oral Maxillofac Surg 1995;53: 784–90. 18. August M, Faquin WC, Troulis MJ, Kaban LB. Dedifferentiation of odontogenic keratocyst epithelium after cyst decompression. J Oral Maxillofac Surg 2003;61:678–83. 19. Philipsen HP. Keratocystic odontogenic tumour. In: Barnes L, Eveson JW, Reichart P, Sidransky D, editors. World Health Organization Classification of Tumours. Pathology and genetics: head and neck tumours. Lyon: IARC Press; 2005. p. 306–7. 20. Reichart PA, Philipsen HP, Sciubba JJ. The new classification of head and neck tumours (WHO)—any changes? Oral Oncol 2006;42: 757–8.
Address: M. Anthony Pogrel Oral and Maxillofacial Surgery University of California San Francisco Room C522 Box 0440 521 Parnassus Avenue San Francisco CA 94143-0440 USA Tel: +1 415 476 8225; Fax: +1 415 476 6305 E-mail: [email protected]
Please cite this article in press as: Pogrel MA. The keratocystic odontogenic tumour (KCOT)—an odyssey, Int J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.ijom.2015.03.008
