The incidence, multiple presentation and recurrence of aggressive cysts of the jaws

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J. Cranio-Max.-Fac. Surg. 16 (1988) 184 195 © Georg Thieme Verlag Stuttgart • New York

The Incidence, Multiple Presentation and Recurrence of Aggressive Cysts of the Jaws Paul J. W. Stoelinga, Frans B. Bronkhorst Dept. of Oral and Maxillofacial Surgery and Dept. of Pathology Municipal Hospital, Arnhem, The Netherlands Submitted 3.3. 1987; accepted 30.6. 1987

Summary The incidence, multiple presentation and recurrence rate of aggressive cysts of the jaws is discussed, based on a study of 677 cysts in 651 patients. Cysts that are considered aggressive include: cysts in which carcinoma develops, unicystic ameloblastoma, keratocysts and calcifying odontogenic cysts. Based on literature studies and on our own material, the incidence and multiplicity of these lesions is calculated. Recommendations for treatment include careful preoperative assessment and treatment of suspicious lesions with excision of the overlying mucosa and fixation of the defect with Carnoy's solution. The cyst in which carcinoma develops should be treated as a true malignancy i. e. by resection. Long term follow-up is necessary to eliminate the possibility of recurrence. Key words

Introduction Cysts in which a carcinoma arises or an ameloblastoma develops, as well as keratocysts and calcifying odontogenic cysts (COC), may be considered aggressive or potentially aggressive in the order mentioned. Their aggressiveness is reflected by their destructive and infiltrative growth (carcinomas and ameloblastomas), their growth potential and their tendency to recur. Cysts in which ameloblastomas develop, keratocysts and calcifying odontogenic cysts often involve one third or more of one jaw and sometimes extend into the soft tissues. Except for keratocysts, for which accurate figures are available, little is known about the incidence of the aforementioned lesions among various series of ordinary jaw cysts. The possible occurrence of multiple cysts is very well documented in the literature (Stoelinga, 1971). The occurrence of multiple keratocysts in the Multiple Basal Cell Naevi (MBCN) syndrome is also well recognized (GorIin and Goltz, 1960). The incidence of multiple keratocysts in non-syndrome patients, however, is not well documented although several authors mention the possibility (Bramley, 1974; Brannon, 1976; Shear, 1976). This study is undertaken to calculate the incidence of the aforementioned lesions and the frequency of multiple occurrences, based on a literature review as well as on our own material. The tendency to recurrence is discussed in relation to the pathogenesis of the recurrences as well as to the practical and clinical implications. Material and Methods This study includes 677 cysts diagnosed in 651 patients over a 13 year period (1973-1985), in the departments of Oral and Maxillofacial Surgery and Pathology. Patients diagnosed as the MBCN syndrome were excluded from this study. All cysts were removed, if possible, by enucleation in one piece. However, in some instances, mostly because of inflammatory reaction, the cyst had to be removed in several pieces and in a few instances, for the same reason, the defect had to be curetted out. Primary closure was carried out except for some cases of infected cysts in which the defect was packed with iodoform-vaseline gauze or

Aggressive cyst - Carcinoma in cyst - Unicystic ameloblastoma - Keratocyst - Calcifying odontogenic cyst - Follow-up - Recurrence

ribbon gauze soaked in Whitehead's varnish. In cases where the cyst extended into the maxillary sinus the defect, after enucleation, was made part of the maxillary sinus and a nasal antrostomy was carried out to ensure adequate drainage. The sinus was also packed with gauze soaked in Whitehead's varnish if haemostasis was required. In cases where the diagnosis of keratocyst or unicystic ameloblastoma was anticipated (Voorsmit et al., 1981) the cyst was removed in conjunction with the mucosa overlying the area where the cyst had perforated through bone at the anterior aspect of the ascending ramus, the area of the maxillary tuberosity, or some part of the alveolar process. This was possible in all cases. Additional perforations seen on the lingual or buccal side of the ascending ramus or through the lower or posterior margin of the mandible were treated by selective electro-cauterization or with Carnoy's solution. The bony defects were also treated with Carnoy's solution, a local fixative (Cutler and Zollinger, 1933), as previously described by Stoelinga and Peters (1973b), and Voorsmit et al. (1981). The mandibular nerve, if exposed over a great length, was carefullly lifted out of its canal and not treated with the Carnoy's solution. Areas where vital roots of neighbouring teeth were involved were also spared with regard to the Carnoy's solution. This protocol was instituted in 20 out of 46 keratocysts. Of the remaining histologically-proven keratocysts 22 were small unilocular cysts located in dentate areas which made them indistinguishable from ordinary jaw cysts and enucleation was not followed by treatment with Carnoy's solution in any of these cases. The four remaining keratocysts retrospectively had the characteristic radiographic features which made them very suspect of being keratocysts or ameloblastomas. However, no preoperative diagnosis was made and therefore the treatment protocol for keratocysts or unicystic ameloblastomas was not followed.

Incidence, Multiple Presentation and Recurrence of Aggressive Cysts of the Jaws J. Cranio-Max.-Fac. Surg. 16 (1988)

18 5

Fig.1 Orthopantomogram showing a poorly demarcated, maxillary, radiolucency (arrows)

nosis. Stoelinga 1971), Wright (1981) and Donath (1985) clearly distinguish between the parakeratotic and orthokeratotic types, both of which have been included in the present study. The histology of COC's is described by Gorlin et al. (1962). They include a basal epithelial layer showing palisading columnar cells often with hyperchromatic nuclei, ghost cells located in the surface of the epithelium and calcification and eosinophilic material resembling dentine in the connective tissue wall. All patients with unicystic ameloblastomas, keratocysts and calcifying odontogenic cysts were seen at regular intervals and radiographs taken to seek evidence of recurFences. Fig.2

Cyst lumen lined by keratinized squamous cell epithelium (C). Arrows point to part of lumen that is lined by a well differentiated squamous cell carcinoma. HE x 5

In 3 cases of unicystic ameloblastoma, the lesion had been treated according to the described protocol for keratocysts. In two cases the histological diagnosis had not been considered since the small cysts were indistinguishable from odontogenic cysts. These defects were treated with Carnoy's solution in a second procedure. The calcifying odontogenic cysts were treated in the same way as other odontogenic cysts, as no special attempt was made to cauterize the defect or excise the overlying mucosa.

The specimens were all examined by one pathologist (F. B. B). The criteria for the diagnosis included a recognizable epithelial lining at least in the main part of the specimen. Serial sections were only made when doubt existed about the section being representative of the lesion or when suspicion arose about the possible aggressive potential of the epithelium. A carcinoma arising de novo in the wall of a cyst was only accepted in this study when part of an ordinary epithelial cyst lining could also be detected. Ameloblastomas arising in cysts were only included when the lesions were unicystic, as suggested by MiilIer (1984). The histological criteria for keratocysts as defined by Soskolne and Shear (1967), Pindborg et al. (1971), Stoelinga (1971) and many others were used for the ultimate diag-

Results From the 651 patients with 677 cysts, 19 patients presented with multiple cysts (2.9 %). In one patient, a carcinoma was diagnosed in the wall of a maxillary cyst (Fig. 1 and 2), part of which was lined by keratinized squamous epithelium. This epithelium, however, did not exhibit the characteristic features of a keratocyst, such as the hyper-

Tab. 1

Unicystic ameloblastomas

Age

Sex

site

1.

18 yrs.

M

Asc. ramus 3rd molar region

2.

17 yrs.

F

3.

18 yrs.

M

4.

76 yrs.

F

5.

60 yrs.

M

Radiographic appearance

Follow-up

Unilocular, bucco-lingual expansion + root resorption 2rid molar Mand. body, Unilocular, angle and bucco-lingual asc. ramus expansion Post. body Unilocular, and asc. bucco-lingual ramus expansion Mand. molar Unilocular. No region expansion

7 years

Max. molar region

2 years

Unilocular, buccal expansion

4 years

272 years

2 years

18 6

J. Cranio-Max.-Fac. Surg. 16 (1988)

P.J.W. Stoelinga, F. B. Bronkhorst Fig.3 (A) Unicystic ameloblastoma (case 2, Table 1 ). Complete regeneration of bone as shown in radiograph taken 4 years later (B).

D

lization in the basal layer (arrow). HE x 6. Insert: island of ameloblastoma with typical hyalinization around it and vacuolization in the basal layer (HE x 30, case 2, Table 1).

Fig. 5 Unicystic amelobtastoma causing resorption of distal root of second molar (A). Note severe buccal and lingual expansion (B). Low power view of specimen (C) with thin epithelial lining (arrows). Lumen (L) and mural ameloblastoma (T). HE x 5

chromatic nuclei in the cells of the basal layer and the palisading arrangement. Most of the wall showed an infiltrative, poorly differentiated, squamous cell carcinoma. In a second procedure a partial maxillectomy was carried out, but this specimen did not show any tumour cells. The patient (a 72-year-old female) died of heart failure 5 weeks after the last operative intervention. In 5 patients (0.77 %) unicystic ameloblastoma was diagnosed (Table 1). In one case (Fig. 3) only a small island of ameloblastoma could be seen, while the major part of the cyst showed the typical features as described by Vickers and Gorlin (1970) (Fig. 4). These characteristic features include columnar basal cells in a palisading arrangement with hyperchromatic nuclei that are polarized away from the basement membrane. The cytoplasm of the basal cells showed vacnolization. The other 4 cases clearly showed mural ameloblastoma with easily recognizable changes in the rest of the cyst lining such as the aforementioned features of Vickers and Gorlin (1970) together with some areas of budding of the basal cell layer and a thin band of hyalinization under the basement membrane as described by Rittersma et al. (1979)(Fig. 5). The overlying mucosa in one case showed a cluster of epithelial islands; in the two

other cases examined no epithelial islands or microcysts could be detected. The 5 patients with unicystic ameloblastomas were followed up from 2 to 8 years, with no signs of recurrence or development of new cystic lesions (Table 1). One case is of particular interest since the onset of the lesion could be traced. This 76-year-old female had periapical radiographs taken by her dentist 4 years before the cyst was detected (Fig. 6). In this elderly individual, an ameloblastoma had arisen within 4 years and had grown to a considerable size. 46 Keratocysts have been diagnosed in 44 patients (6.7 %) (Fig. 7). Two patients each had two separate cysts (4.6 %). In one of these patients a third keratocyst was detected in a different location 8 years after initial treatment. In another patient a giant maxillary cyst had been removed 6 years before a new cyst developed in the mandible. The first cyst had a very thin two-layered epithelial lining but showed no keratinization. The second cyst showed the typical features of the orthokeratotic variant of the keratocyst as recognized by Wright (1981)(Fig. 8). The 46 keratocysts could be histologically defined as follows: 42 had a thin, predominantly parakeratotic, epithel-

Fig.4 Cyst lining of unicystic ameloblastoma with areas of vacuo~

Incidence, Multiple Presentation and Recurrence of Aggressive Cysts of the Jaws J. Cranio-Max.-Fac. Surg. 16 (1988)

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Fig. 6 Unicystic ameloblastoma developing over a 4 year period (A and B). Note root resorption (B and C). Specimen showing thin epithelial cyst lining with ameloblastic changes in its wall (D). HE x 5

Fig.7 The location of 46 keratocysts. Maxilla: 9, mandible: 37.

L ial lining with palisading columnar or cuboidal basal cells and hyperchromatic nuclei in the basal cells (Fig. 9). In many instances vacuolization of the cytoplasm was seen in the spinous layer. In areas with inflammatory reactions, the epithelium had lost its characteristic appearance and was sometimes almost indistinguishable from ordinary jaw cysts as described by Stoelinga (1971), Shear (1976), Brannon (1977), Reff and Donath (1983) and Voorsmit (1984). Four cysts exhibited the orthokeratotic variant with an abundance of orthokeratosis in the superficial layers and variable thickness of the epithelial layer with or without the cuboidal or columnar basal cells.

R From the 20 cases in which the overlying mucosa had been excised 17 showed clusters of epithelial islands and/or micro-keratocysts in the overlying part of the mucosa (Fig. 9). Microcysts were never seen in other parts of the cyst wall and epithelial islands seen only sporadically. In order to calculate the recurrence rate the 44 patients were divided into 2 groups according to the length of postoperative follow-up. The first group consists of 27 patients in whom the follow-up ranged from 5 - 1 3 years (mean 8.8 years). In one patient a recurrence was seen one year after the initial treatment (Fig. 10). Retrospectively, this cyst should have deserved special attention, but no

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J. Cranio-Max.-Fac. Surg. 16 (1988)

P. J. W. Stoelinga, F. B. Bronkhorst

Fig. 8

Giant maxillary cyst (A and B) removed via a CaldwelI-Luc approach in a 62-year-old man. Six years later a keratocyst in the left mandible was removed (C, arrows). The keratocyst exhibited a thin tayer of epithelium with abundant orthokeratosis in some parts of its lining. (D and E) (HE x 5, insert HE x 50)

'

E

D

aspiration biopsy was carried out and thus a preoperative diagnosis was not made. The cyst was therefore not treated according to the protocol advocated. Another recurrent cyst was seen in a patient who had a large cyst in the a s -

cending ramus of the mandible. The recurrence was detected on the anterior aspect of the ramus 2 >L'ars a~ t,r the initial treatment. The original cyst, as well as the recurrence, had numerous epithelial islands in the mucosa overlying the anterior perforation. The case, previously published by Voorsmit et al. (1981), was treated according to the protocol advocated. Five patients in this group were not available for recent examination, 4 having died, and one patient having left the country. The recurrence rate in this group could be calculated as varying between 7.4% and 9.8 % depending on how one wants to view the number of patients (27 or 22). The second group comprises 17 patients in w h o m the follow-up ranges from 1 - 4 years (mean 2.3 years). One patient from this group has died, but no recurrent cyst has been found in the group. Four patients exhibited a single COC each (0.61%) (Table2, Fig. 14). In 3 patients large mandibular cysts were seen involving more than one-third of the horizontal part of the mandible with buccal expansion (Fig. 11 and 13). In one case a small lateral periodontal cyst distal to a third molar showed the characteristic features of a calcifying odontogenic cyst (Fig. 12). One recurrent calcifying cyst was found 8 years after initial treatment (Fig. 13). The others respectively 7, 3 and 1 years postoperatively showed no signs of recurrence.

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~8 9

Fig. 9 Large multilocular keratocyst occupying half of the mandible (A). Defect packed with ribbon gauze soaked in iodine-vaseline (B). Radiograph showing good bony healing 1 year later (C). Typical lining of the keratocyst showing parakeratesis and palisading of the basal layer cells (D). (HE x 60) Overlying mucosa showing several epithelial islands and microcyst (E) (HE x 3).

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P.J.W. Stoelinga, F. B. Bronkhorst Fig.lO Multilobular keratocyst (A)in the right angle of the mandible extending into the ramus. Multilocular recurrence (B and C).

Tab.2

Calcifying odontogenic cysts

Age

Sex

Site

Radiographic appearance

Follow-up

1.

18 yrs.

M

Symphyseal area

8 years recurrence

2.

56 yrs.

F

Symphyseal area

3.

22 yrs.

M

Latero-follicular. Upper right canine

4.

19 yrs.

M

Latero-foIlicular, left lower 3rd molar

Unilocular, bucco-lingual expansion + root resorption, calcification in lumen Unilocular, bucco-lingual expansion + root resorption, calcification in lumen Unilocular, buccal expansion, calcification in lumen Unilocular

Fig.lOc

Discussion

Since no other Oral and Maxillofacial service exists in the immediate neighbourhood and only a few cases were referred from the region outside Arnhem, the material can be considered non-selective. It therefore represents fairly accurately the variety that may be seen in a population of patients who present themselves with cysts of the jaws. The cysts in this study are purposely not classified according to their supposed aetiology or pathogenesis. Retrospective interpretation of incomplete case histories, descriptions of clinical features and evaluation of radiographs taken from only one direction leave too much

7 years

3 years

1 year

room for subjective opinions and may thus lead to false conclusions. This is particularly the case if one tries to relate histological findings to the type of cyst. The literature is replete with such studies which tend to add to the con-

Incidence, Multiple Presentation and Recurrence of Aggressive Cysts of the Jaws J. Cranio-Max.-Fac. Surg. I6 (1988)

Fig. 11

191

Calcifying odontogenic cyst in the symphyseal area of the mandible causing extensive buccal expansion (A and B).

Fig,12 Small lateral-periodontal cyst that exhibited the histological characteristics of a COC,

Fig.13a

Fig. 13 Large cyst in anterior region of the mandible causing buccal expansion and resorption and displacement of the roots of the teeth (A and B). Radiograph taken 8 years later (C) shows vague radiolucency in anterior region. Periapical film (D) shows well defined lesion. Histological examination revealed a recurrent COC.

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Fig. 14

(A) Fragment of cyst wall from Fig. 13 (HE x 8). (B) Shows part of cyst lining in which hyperchromatic, columnar basal ceils can be seen in a palisading arrangement. Ghost ceils and eosinophilic masses within the epithelium are present (HE x 40).

fusion that already exists regarding the question as to whether a certain type of epithelium may be present in a certain type of cyst (Donoff et al., 1972; Brannon, 1976 and 1977; Chuong et al., 1982; Shear, 1983; Donath, 1985). There is certainly a need for prospective studies in which careful documentation is done on the basis of detailed clinical and radiographic examination and above all the morphology is described on the basis of peroperative findings. Only then can progress be made with respect to the knowledge of the pathogenesis of cysts. The figure found for the occurrence of multiple ordinary jaw cysts is somewhat lower than found in a previous study (Stoelinga, 1973). However, no follow-up on all pa-

P. J. W. Stoelinga, F. B. Bronkhorst tients with cysts has been carried out in the present study which may explain this lower figure. Nevertheless, some individuals exhibit a tendendy towards cyst development which cannot be explained. Some patients even have 3 or more cysts. Malignancies arising in the wall of cysts are reported to be rare. Calculation of their incidence is difficult as there have been insufficient series of cysts reported in which attention has been paid to this phenomenon. Furthermore, many cases of reported central carcinomas suggestive of malignant transformation in the wall of a cyst are difficult to accept since the documentation is poor or the actual transformation cannot be seen. Eversole et al. (1975) estimated on the bases of 32 accepted cases of central carcinoma that 75 % were associated with a cyst whereas 13 of 27 cases (48 %) of central mucoepidermoid cysts were related to a cyst or an impacted tooth. Gardner (1975) reviewed the literature and found 25 acceptable cases of squamous cell carcinoma arising in a cyst. Several reports of proven cases from the English, Dutch and German literature published since that publication, including our own case, have increased this number to 45 (Stoelinga and Peters, 1973 a; Martinelli et al., 1977; Frankl and Bouyssou, 1977; Baker et al., 1979; Birke et al., 1979; Enriques et al., 1980; Areen et al., 1981; Nithiananda, 1983; Rothler et al., 1984; Voorsmit, 1984; van der Waal et al., 1985; Donath, 1985; Kreidler et al., 1985). Some information on the incidence of carcinomas arising in cysts related to carcinomas of the oral cavity is available. Van der Waal et al. (1985) found 5 cases in 292 oral carcinomas (1.8 %). Otten et al. (1985) had 5 cases of central carcinoma in 371 oral carcinomas (1.6 %). Only two cases are probably associated with cysts (0.55 %) although histological evidence is not given. Frankl and Bouyssou (1977) presented four cases of carcinoma arising in odontogenic cysts in a series of 1300 cysts (0.31%), however, only two cases are sufficiently well documented. Donath (1985) reported on one squamous cell carcinoma and two mucoepidermoid tumours in 2132 cases of cysts. Kreidler et al. (1985) found one proven case of squamous cell carcinoma in 758 cysts. This finding coincides with the incidence found in the present study. In a previous survey on 486 cysts, one case with a carcinoma in situ had been found (Stoelinga and Peters, 1973 a). On the other hand several series of cysts have been reported in which no malignant changes have been mentioned (Killey et al., 1977; Shear, 1983). Nevertheless, it seems justified to estimate the incidence of malignant change including squamous cell carcinoma and mucoepidermoid tumour as varying from 1 - 2 %0. Further epidemiological studies are necessary to substantiate or readjust this figure. There is no reason to believe that a carcinoma arising in a cyst would behave differently from any other carcinoma affecting the jaw-bones. Resection with wide margins is therefore the method of choice. The tendency to recur will be high depending on the degree of infiltration and on possible spread to the lymph nodes. The term unicystic ameloblastoma refers to a unilocular cyst in which an ameloblastoma is found (Robinson and Martinez, 1977; Miiller, 1984). Whether such a lesion in fact is a mural ameloblastoma originating in the wall of a jaw cyst or represents a cystic development in an ameloblastoma, remains uncertain. Both pathogenetic routes,

Incidence, Multiple Presentation and Recurrence of Aggressive Cysts of the Jaws J. Cranio-Max.-Fac. Surg. 16 (1988) however, may lead to a cystic lesion which may be indistinguishable from any other cyst of the jaws. The matter is therefore purely academic and not relevant in the differential diagnosis of cystic lesions. The incidence of unicystic ameloblastomas among various series of jaw cysts is not documented except for 2 reports. Frankl and Bouyssou (1977) reported on 5 ameloblastomas arising in the wall of odontogenic cysts in a series of 1300 cysts (0.39 %). In a previous study, 5 unicystic ameloblastomas were found among 486 cysts (Stoelinga, 1971). The present study with 5 cases among 677 cysts, appears to confirm the ratio of approximately 1%. If one calculates the incidence among cysts of the mandible, this figure increases. Stoelinga (1971) found this incidence to be more than 3 % and in the present study (4 cases in 250 cysts) it amounts to 1.6 %. The incidence of unicystic ameloblastoma among various series of ameloblastomas is reported to vary from 5 to 25 %, depending on whether one includes both possible variations i. c. mural ameloblastoma in a cyst and cystic ameloblastoma (Sonesson, 1950; Lucas, 1954; Mehlisch et al., 1972; Sbteyer et al., 1978). The recurrence rate of solid and polycystic ameloblastomas appears to be much higher compared with unicystic ameloblastoma. Many authors therefore recommend conservative treatment of the unicystic variant (Dara.nola et al., 1975; Hardt and Steinbduser, 1979; Gardner and Pecak, 1980; McMillan and S.nillie, 1981; MiilIer, 1984). The findings in this study are in agreement with the aforementioned opinion. Enucleation and fixation with Carnoy's solution seems to be an appropriate treatment, particularly when one realizes that the solution does not penetrate the bone any deeper than 1.54 ram. after 5 minutes and 1.81mm after 1 hour (Voors.nit, 1984). In areas where the ameloblastoma has perforated through the bone, selective cauterization is recommended. Preoperative assessment of suspicious lesions should include aspiration and estimation of the protein content as well as cytological examination of smears. The results of the test will reveal no differences from ordinary cysts but are quite different from the results in keratocysts (Kra.ner and Toiler, 1973; Voors.nit, 1984). From a radiological point a view unicystic ameloblastomas may resemble keratocysts in that they are also located in the third molar region and ascending ramus of the mandible in the majority of cases. Unlike keratocysts, however, they tend to cause more expansion whereas root resorption is also a common feature in unicystic ameloblastoma (Voors.nit, 1984). The case reported in this study in which the onset of the lesion could be traced (Fig. 6 and 7) is of special interest in that it indicates that in elderly individuals epithelial remnants can still be triggered to form tumours. It also demonstrates the often impossible task of classifying cysts. This cyst enveloped two vital roots and probably had nothing to do with the molar, yet, if the molar had been extracted, the diagnosis of residual cyst would probably have been made. This case illustrates the trivial value of classification. The incidence of keratocysts among cysts of the jaws is reported to vary from 1.5 %-17.4 % (Voors.nit, 1984). The differences may be explained b y several factors. Many of these series are reported by pathologists, which implies that some selection has taken place, for surgeons tend not to submit all their cysts for histological examination. Other series come from University centres which also tend

19 3

to enhance selection, as the larger and more complicated cases are likely to be sent to these centres. Some studies include keratocysts present in patients with the MBCN syndrome. This tends to increase the incidence figure because these patients usually have multiple cysts. The present study gives an actual percentage because the material can be considered non-selective. The incidence of multiple keratocysts not related to the MBCN syndrome is difficult to obtain from the literature, although in many instances the possibility is mentioned. Payne (1972) mentions the possible occurrence of multiple keratocysts and suspects hereditary influence. He found 85 keratocysts in 81 patients, but does not give further details. Bra.nley (1974) also promotes the possible familial tendency for multiple keratocysts. Brannon (1976) found 10 out of 283 patients with keratocysts who had multiple cysts (3 %). Vedtofte and Praetorius (1979) had 3 cases with multiple cysts in a group of 72 patients (4 %). Ahlfors et al. (1984) found l l with multiple keratocysts in a group of 251 patients (4%) and Voors.nit (1984) 2 patients with 2 keratocysts each in a group of 101 patients (2%). The percentage found in this study (4.5 %) is in agreement with those mentioned above. The one patient who developed a third keratocyst after 8 years seems to emphasize the point that patients with multiple keratocysts require long term follow-up. A familial trend could not be detected in our patients. The high recurrence rates as found in several studies varying from 2.5-62.5 % are listed by Voors.nit (1984). The figures are highly variable and depend on follow-up period, treatment modality and on the way one wants to calculate the recurrences. The very low percentages as claimed by Voors.nit et al. (1981), Voors.nit (1984) and by the present study, seem to justify the treatment protocol as previously described (Stoelinga, 1973; Voors.nit et al., 1981). The excision of the overlying mucosa in the area where the cyst herniates through the anterior aspect of the ascending ramus presumably eliminates the source of newly developing cysts that are erroneously called recurrences. These perforations have always been found in our material. Retrospective studies that claim that these perforations do not exist should be viewed in the light that one does not tend to see the signs and symptoms that one does not anticipate (Far.nand and Makek, 1983). In cases where cysts are located in the tooth-bearing area, careful inspection of the area where the cyst is attached to the gingiva or mucosa overlying the tuberosity should be carried out in order to be able to excise that part. The use of Carnoy's solution to mop out the defect is a safe and conservative means of eliminating possible remnants of the cyst membrane or offshoots of the basal layer of the keratocyst epithelium. True recurrences can thus be avoided. The inferior alveolar nerve will not be damaged by contact with Carnoy's solution according to Voors.nit (1984). Fixation of keratocysts before enucleation as reported by Voors.nit (1984, 1985) may be a useful adjunct in the management of those keratocysts The incidence of COC among cysts of the jaws has never been reported.The present figure (0.61%) has to be confirmed by other studies. Reports of multiple COC's have as yet not been published. Most authors agree that the COC is a benign lesion which can be treated by enucleation (Freedman et al., 1975; Altini and Far*nan, 1975), yet, that are difficult of access or that show large areas of adherence to soft tissues.

194

J. Cranio-Max.-Fac. Surg. 16 (1988)

several recurrent COC's are reported (Gorlin et al., 1962; Swinson, 1976; D o n a t h et al., 1979; Slootweg and Koole, 1980; Wright et al., 1984). The recurrences reported tend to be detected 5 years or more after treatment of the initial lesion. This was also the case in the patient reported in this study. Both Swinson (1976) and D o n a t h et al. (1979) present one recurrence out o f 4 COC's. The same figure has been found in this study (25 %). This fairly high recurrence rate should be considered with some reservation since the numbers involved are small. Nevertheless, these figures should alert the clinician to follow-up patients with COC on a regular basis over at least a 10 year period, to identify any possible recurrence. The use of Carnoy's solution for this lesion m a y be recommended since it is very likely that the recurrence develops from remnants of the original cyst that are left behind in the defect. References Ahlfors, E., A. Larsson, S. Sjogren: The odontogenic keratocyst: a benign tumor? J. Oral Maxillofac. Surg. 42 (1984) 10 Aitini, M., A. G. Farman: The calcifying odontogenic cyst. Oral Surg. 40 (1975) 751 Areen, R. G., K. D. McClatchey, H. L. Baker: Squamous cell carcinoma developing in an odontogenic keratocyst. Report of a case. Arch. Otolaryng. 107 (1981) 568 Baker, R. D., E. D. D'Onoforio, R. L. Corio, B. E. Crawford, B. C. Terry: Squamous-cell carcinoma arising in a lateral periodontal cyst. Int. J. Oral Surg. 47 (1979) 495 Birke, W. P., H. J. Koch, D. Tessmann: Maligne Entartung einer radikularen Residualzyste. Stomatol. DDR 29 (1979) 382 BramIey, P. A.: The odontogenic keratocyst, an approach to treatment. Int. J. Oral Surg. 3 (1974) 337 Brannon, R. B.: The odontogenic keratocyst. A clinico-pathologic study of 312 cases. Part I. Clinical Features. Oral Surg. 42 (1976) 54 Brannon, R. B.: The odontogenic keratocyst. A clinico-pathologic study of 312 cases. Part II. Histological features. Oral Surg. 43 (1977) 233 Chuong, R., R. B. Donoff, W. Guralnick: The odontogenic keratocyst. J. Oral Maxillofac. Surg. 40 (1982) 797 Cutler, E. C., R. Zollinger: Sclerosing solution in the treatment of cysts and fistulae. Amer. J. Surg. 19 (1933) 411 Daramola, J. 0., H. A. Ajagbe, J. 0. Oluwasanmi: Ameloblastoma of the jaws in Nigerian children. Oral Surg. 40 (1975) 458 Donath, K.: Odontogene und nicht-odontogene Kieferzysten. Dtsch. Zahn~rzti. Z. 40 (1985) 502 Donath, K., V. Kleinhans, K. K. H. Gundlach: Zur Pathogenese der kalzifizierenden odontogenen Zyste. Virchows Arch. Path. Anat. Histol. 384 (1979) 307 Donoff, R. B., W. C. GuraInick, L. Clayman: Keratocysts of the jaws. J. Oral Surg. 30 (1972) 800 Enriquez, tL E., B. Ciola, S. L. Bahn: Verrucous carcinoma arising in an odontogenic cyst. Oral Surg. 49 (1980) 151 Eversole, L. tL, W. R. Sabes, S. Rovin: Aggressive growth and neoplastic potential of odontogenic cysts. Cancer 35 (1975) 270 Farmand, M., M. Makek: Late results following Brosch-procedure for treating large mandibular ramus cysts. J. Max.-Fac. Surg. 11 (1983) 211 Frankl, Z., M. Bouyssou: Pr~kanzerose und maligne Ver~inderungen in der Auskleidung odontogener Zysten und ihre therapeutischen Konsequenzen. Quintessenz 9 (1977) 15 Freedman, P. D., H. Lumerman, J. K. Gee: Calcifying odontogenic cyst. Oral Surg. 40 (1975) 93 Gardner, A. F.: A survey of odontogenic cysts and their relationship to squamous cell carcinoma. J. Canad. Dent. Assoc. 3 (1975) 270

P. J. W. Stoelinga, F. B. Bronkhorst Gardner, D. G., A. M. J. Pecak: The treatment of ameloblastoma based on pathologic and anatomic principles. Cancer 46 (1980) 2514 Gorlin, R. J., J. J. Pindborg, F. P. Clausen, R. A. Vickers: The calcifying odontogenic cyst - A possible analogue of the cutaneous calcifying epithelioma of Malherbe; an analysis of fifteen cases. Oral Surg. 15 (1962) 1235 GorIin, R. J., R. W. Goltz: Multiple nevoid basal cell epithelioma, jaw cysts and bifid rib. New Engl. J. Med. 262 (1960) 908 Hardt, v. N., E. W. Steinhduser: Zur Therapie und Prognose zirkumscripter Ameloblastome in odontogenen Zysten. Dtsch. Z. Mund-, Kiefer- und Gesichtschir. 3 (1979) 139 Killey, H. C., L. W. Kay, G. R. Seward: Benign cystic lesions of the jaws, their diagnosis and treatment. 3rd ed. Livingstone, Edinburgh 1977 Kramer, I. R. H., P. A. Toiler: The use of exfoliative cytology and protein estimations in preoperative diagnosis of odontogenic keratocysts. Int. J. Oral Surg. 2 (1973) 143 Kreidler, J., S. Haare, W. Kamp: Karzinomagenese in Kieferzysten. Dtsch. Zahn~irztl. Z. 40 (1985) 548 Lucas, R. B.: Neoplasia in odontogenic cysts. Oral Surg. 7 (1954) 1227 MartineIli, C., R. M. Melhado, E. A. Callestini: Squamous-cell carcinoma in a residual mandibular cyst. Oral Surg. 44 (1977) 274 McMillan, M. D., A. C. Smillie: Ameloblastomas associated with dentigerous cysts. Oral Surg. 51 (1981) 489 Mehlisch, D. R., D. C. Dahling, J. K. Masson: Ameloblastoma: a clinico pathologic report. J. Oral Surg. 30 (1972) 9 Mi~Iler, H.: Het ameloblastoom. Thesis, University of Utrecht. Drukkerij Juten B. V., Bergen op Zoom 1984 Nithiananda, S.: Squamous cell carcinoma arising in the lining of an odontogenic cyst. Br. J. Oral Surg. 21 (1983) 56 Otten, J. E., U. Joos, W. Schilli: Karzinomentstehung auf dem Boden des Zystenbildenden odontogenen Epithels. Dtsch. Zahn~irztl. Z. 40 (1985) 544 Payne, T. F.: An analysis of the clinical and histopathologic parameters of the odontogenic keratocyst. Oral Surg. 33 (1972) 538 Pindborg, J. J., L R. Kramer, H. Torloni: Histological typing of odontogenic tumours, jaw cysts and allied lesions. Int. histological classification of turnouts No. 5, World Health Organisation, Geneva 1971 Reff, G., K. Donath: Zur pathohistologischen Diagnostik nicht-entzfindeter und entziindeter odontogener Keratozysten. Dtsch. Z. Mund-, Kiefer- und Gesichtschir. 7 (1983) 267 Rittersma, J., H. N. Hadders, K. Feenstra: Early unicystic ameloblastoma, J. Oral Surg. 37 (1979) 747 Robinson, L., M. G. Martinez: Unicystic ameloblastoma. Cancer 40 (1977) 2278 Rothler, G., E. WaIdhart, B. Norer: Karzinomatose Entartung einer Residualzyste. Z. Stomatol. 81 (1984) 113 Shear, M.: Cysts of the oral regions. Wright, Bristol 1976 Shear, M.: Cysts of the oral regions. 2nd ed. Wright, Bristol (1983) 142 Shteyer, A., J. Lustmann, J. Lewin-Epskin: The mural ameloblastoma. J. Oral Surg. 36 (1978) 866 Slootweg, P. J., R. KooIe: Recurrent calcifying odontogenic cyst. J. Max.-Fac. Surg. 8 (1980) 143 Sonesson, A.: Odontogenic cysts and cystic tumors of the jaw. Acta radiol. Suppl. 81 (1950) 59 Soskolne, W. A., M. Shear: Observations on the pathogenesis of primordial cysts. Brit. Dent. J. 123 (1967) 321 Stoelinga, P. J. W.: Over kaakkysten. Thesis University of Nijmegen. Centrale Drukkerij B. V., Nijmegen 1971 Stoelinga, P. J. W., J. H. Peters: Kaakkysten met een 'agressief' gedrag. Ned. Tijdschr. Geneesk. 117 (1973 a) 143 Stoelinga, P. J. W., J. H. Peters: A note on the origin of keratocysts of the jaws. Int. J. Oral Surg. 2 (1973 b) 37 Stoelinga, P. J. W.: Recurrences and multiplicity of cysts. In: Kay, L. W. (Ed.). Oral Surgery, Transactions of the IVth International Conference on Oral Surgery. Munksgaard, Copenhagen (1973) 77

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P. J. W. Stoelinga M.D., D.M.D. Dept. of Oral and Maxillofacial 8urg. Municipal Hospital Wagnerlaan 55 6815 AD Arnhem The Netherlands