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Clinicopathologic study of the postoperative maxillary cyst
Clinicopathologic study of the postoperative maxillary cyst Hirotsugu Yamamoto, D.D.S., Ph.D.,* and Minoru Chiba and Tokyo, Japan
Takagi, D.D.S., Ph.D.,**
PATHOLOGYSECTION,CENTRALLABORATORlESOFNlHON UNlVERSlTYSCHOOLOFDENTlSTRYAl MATSUDO,ANDDEPARTMENTOFORALPATHOLOGY,TOKYOMEDlCALANDDENTALUNlVERSlTY Sixty cases of the postoperative maxillary cyst were studied clinicopathologically. The cysts accounted for 19.5% of all oral cystic lesions. Most of the patients were in their 20s and 30s at the time of diagnosis, and the postoperative duration was between 10 and 49 years. Radiographically, most cases revealed a unilocular cystic lesion. In two thirds of the cases, the lesion occupied more than half the volume of the maxillary sinus while the remaining one third of the cases revealed more limited lesions of the sinus. Histopathologically. cuboidal, squamous, and mixed epithelial cyst linings were observed, although the basic epithelial lining was the ciliated columnar type. Epithelial dysplasia was found in two cases. The cysts near the nasal cavity may originate from regenerated nasal mucosa, and the cysts that are located at a distance from the nasal cavity may be lined with epithelium derived from residual mucosa of the sinus entrapped during surgery to relieve sinusitis. (ORAL SURG. ORAL MED. ORAL PATHOL. 62544-548,
1986)
T
he postoperative maxillary cyst occurs as a delayed complication following maxillary radical surgery.‘-3 Kubo4 reported the first case in 1927. After that, he added three cases and termed them postoperative Wangenzyste in 1933.5 Since then, many caseshave been reported, mainly in the Japanese literature. They have been reported under several names including mucocele and postoperative paranasal cyst.6-‘3 In 1958, Gregory and ShaferI described these cystic lesions in the English literature as “surgical ciliated cysts of the maxilla.” Although the lesion is relatively common in Japan, it appears to occur less frequently elsewhere.‘-3s 6.I3The purpose of this article is to study the clinicopathologic features of 60 postoperative maxillary cysts. MATERIALS
AND METHODS
The case material consisted of 60 postoperative maxillary cysts, which were diagnosed from 1976 to 1981 at the Pathology Section, Central Laboratories, Nihon University School of Dentistry at Matsudo. All cases were confirmed by histologic examination of excised specimens. Following fixation with 10% *Assistant Professor of Clinical Pathology, Nihon University. **Associate Professor of Oral Pathology, Tokyo Medical and Dental University. 544
Table I. Sex and age distribution at diagnosis of postoperative maxillary cyst Age
Male
Female
Total cases
20-29 30-39 40-49 50-59 60-69 70-79 Total
5 15 8 1 0 1 30
3 13 10 2 2 A! 30
8 28 IX 3 2 _1. 60
neutral formalin, routine paraffin sections were made. They were stained with hematoxylin and eosin, periodic acid--Schiff (PAS), PAS-alcian blue (pH 2.5) alcian blue (pH 0.4, 1.O, 2.5) azan Mallory, PAM, and van Gieson stains. RESULTS
Sex and age distribution are shown in Table I. Of 60 patients, 30 were males and 30 were females. Most were in their 20s and 30s. No patients were younger than 20 years old. The mean age was 39.1 years, with a range of 21 to 72 years. The duration between the first surgical procedure and the time of
Postoperative
Volume Number
62 5
Table
II. Time between radical surgery and diagno-
maxillary
cyst
545
sis Years
No. of cases
o-9 IO-19 20-29 30-39 40-49
4 32 20 2 2
diagnosis of postoperative maxillary cyst is shown in Table II. For 87% of the patients, the duration ranged between 10 and 29 years, with a mean of 18.3 years. The shortest period was 4 years; the longest period was 49 years. Thirty-seven cases were from the right maxilla, while 23 were from the left. Most (93%) were unilocular cystic lesions, with only four cases reported as being multilocular. A study of the size and location of the cysts showed that 24 cases (40%) occupied half of the maxillary sinus (Fig. l), 19 cases were localized in the lower portion of the sinus, and 17 cases occupied the entire sinus. In 42 cases, the buccal cortical bone was present; in 18 cases it was not. Surrounding bone sclerosis was evident in at least a portion of the bony margin in 58% of the cysts, whereas in the remaining cases this condition was missing. Most cases were located in the molar and premolar regions. Macroscopically, most cysts exhibited a wall of variable thickness and primarily contained brown mutinous or, rarely, serous fluid (Fig. 2). Purulent fluid and cholesterol crystals were found in several cases. Microscopically, it could be seen that most cysts were lined with ciliated columnar, cuboidal, or squamous epithelium (Figs. 3, 4). The majority of the cysts were lined with ciliated columnar epithelium. With increased duration, however, there was an increase in the proportion of cuboidal, squamous, and mixed epithelia. Occasional goblet cells were evident within the columnar epithelium. In addition, atypical epithelial changes were observed in two cases; one exhibited moderate dysplasia, and the other exhibited severe dysplasia (Fig. 5). The basement membrane was thickened in several cases, especially in cases with connective tissue hyalinization. Changes in the connective tissue of the cysts included fibrosis associated with hyalinization, inflammatory cell infiltration, and edema (Figs. 3, 4). In early lesions, edema and an inflammatory cell infiltrate were frequent findings. Dilated nasal glands (sometimes with apocrine metaplasia), calci-
Fig. 1. Panoramic radiograph showing unicystic lesion in maxillary sinus with surrounding bone sclerosis above molar and premolar regions (arrow).
2. Macroscopically, exhibits thick cystic wall.
Fig.
complete enucleated lesion
fication, cholesterol granulomas, metaplastic bone formation, and capillary dilatation were also seen. DISCUSSION
The postoperative maxillary cyst is a common lesion in Japan, but it is relatively rare in European countries and America. However, reports of similar lesions are found in several articles from these countries. BelaP described the first case of this entity in a 30-year-old woman. There have also been other reports, under several names, from different countries.‘4* ‘6-22 Recently, Gardner23 attempted to clarify the nature of the dome-shaped pseudocysts and retention cysts of the maxillary sinus. These two cysts are supposed to be different from the postoperative maxillary cyst. The pseudocyst of the maxillary sinus is composed of a cavity surrounded by a dense,
546
Yamamoto
and Takagi
Oral November,
Surg. 1986
Fig. 3. Microscopically, inner surface of cyst is lined with ciliated columnar and cuboidal epithelia with fibrosis, inflammatory cell infiltration, and cholesterol crystal slits. Lm. Lumen. (Hematoxylin and eosin X 100.) stain. Magnification,
Fig. 4. Inner surface of cyst is covered with metaplastic squamous epithelium hyalinization. Lm, Lumen. (Hematoxylin and eosin stain. Magnification, X 260.)
layer of fibrous connective tissue beneath the sinus mucosa, with no glands or ducts and containing inflammatory exudates. The retention cyst consists of a pseudostratified columnar epitheliurn-lined cavity, which is produced by partial blockage of the duct of seromucinous glands of the sinus, resulting in dilatation of the duct into a cystic structure. On the other hand, the postoperative maxillary cyst is lined with ciliated, cuboidal, or squamous epithelium and supported with hyslinized connective tissue. compact
with
fibrosis
and
In our hospital the postoperative maxillary cyst accounted for 19.5% of all oral cystic lesions. There were 307 cases of oral cystic lesions, which consisted of 178 odontogenic cysts and 129 nonodontogenic cysts. Therefore, the incidence of the postoperative maxillary cyst within the latter was 46.5%, which was the most common form of nonodontogenic cyst. Ito and co-workers’ and Manba9 reported a 23.6% and a 20.3% incidence of this lesion, respectively. Thus, the postoperative maxillary cyst is one of the most often encountered nonodontogenic cysts in
Volume Number
Postoperative
62 5
Fig.
5. Marked
epithelial
dysplasia. (Hematoxylin
Japan. Although the postoperative maxillary cyst was not described in Histological Typing of Odontogenic Tumours by the World Health Organization,24 this pathologic concept had been accepted as a distinct entity. Most patients were diagnosed as having a postoperative maxillary cyst in their 20s and 30s and had undergone radical maxillary surgery in their first two decades of life. For the diagnosis of postoperative maxillary cyst, it is important to bear in mind the history of previous maxillary surgery. Radiographically, most of our cases appeared as unilocular cystic lesion occupying half of the maxillary sinus, but some were localized or diffuse, and they involved the premolar and molar regions, as reported by others.‘) A zone of sclerosis surrounding the cyst was found in 58% of all cases. Tachikawa’O and Kaneshiro and colleaguesi reported an incidence of 66.7% and 68%, respectively, while Ohba’s group’* stated that this sclerotic zone was less frequently observed. PsennerZ5 indicated that early lesions were radiographically inconspicuous, whereas older lesions were readily apparent. Although the most common epithelium lining the cyst was of the ciliated columnar type, cuboidal, squamous, and mixed epithelial types were also frequently seen. Tachikawa’O also reported a 41% incidence of squamous metaplasia in the epithelia of the cysts. Manasse26 stated that metaplasia was often present in such cases, especially in areas of fibrosis and granuloma formation. Squamous metaplasia and the transition into cuboidal cells represents a regressive alteration. These changes may be caused by various types of chronic stimulation or inflammation.
and eosin stain. Magnification,
maxillary
X
cyst
547
800.)
The atypical epithelial changes that may occur in this cyst have not been described previously. We observed moderate to severe dysplasia in two cases. Several hypotheses have been proposed to explain the pathogenesis of the postoperative maxillary cyst. Kubo4s5 suggested two theories: (1) that the cyst might be caused by residual mucosa of the maxillary sinus being trapped in the wound resulting from a surgical procedure for treatment of sinusitis and (2) it might be caused by the retention of tissue fluid or blood forming a tissue space or sinus after the operation. Imai6 proposed that the cyst also might originate from regenerating mucosa within the sinus derived from the nasal cavity. In the present study, two thirds of the cases showed occupation of all or half of the maxillary sinus near the nasal cavity, and one third were localized to the lower portion of the sinus at a distance from the nasal cavity. The postoperative maxillary cyst is a form of retention cyst and occurs during the healing process after radical surgery for treatment of sinusitis. Therefore, cysts near the nasal cavity may arise from regenerated mucosa of the sinus or from the nasal mucosa, whereas cysts that are located at a distance from the nasal cavity may arise from residual mucosa of the sinus entrapped during surgery. REFERENCES 1. Shafer WG, Hine MY, Levy BM: A textbook of oral pathology, ed. 4, Philadelphia, 1983, W.B. Saunders Company, p. 545. 2. Van der Waal I.: Dental pathology slide seminar, ed. 3, Transactions of the IX European Congress of Pathology in Hamburg, 1983. 3. Lucas RB: Pathology of tumours of the oral tissues, ed. 4, Edinburgh, 1984, Churchill Livingstone, p. 382.
548 Yamamoto and Takagi
9.
10. 11.
12. 13.
14. 15. 16. 17.
Kubo I: A buccal cyst occurred after a radical operation of the maxillary sinus. Z Otol Tokyo 33: 896-897, 1927. Kubo I: Postoperative Wangenzyste. Z Otol Tokyo 39: 1831-1845, 1933. Imai T: Mucocele of the maxillary sinus after radical operation for sinusitis. Z Otol Tokyo 39: 723-735, 1933. Ito H: Clinicostatistical study of jaw cysts. J Jpn Stomatol Sot 18: 241, 1969. Kudo K, Fujioka Y, Ohashi Y: Clinicopathological study of postoperative maxillary cysts. J Jpn Stomatol Sot 21: 250257, 1972. Manba M: Clinical statistical observation of cysts of the oral region during the last five years. Niigata Dent J 4: 17-26, 1974. Tachikawa J: Clinicopathological study of postoperative maxillary cysts, Shika Gakuho 75: 1117-l 142, 1975. Onodera A, Sato M, Takahashi T: Electron microscopic studies of the postoperative maxillary cyst. Jpn J Otol 81: 918-925, 1978. Ohba T, Yang R, Chen C, Uneoka M: Postoperative maxillary cyst. Int J Oral Surg 9: 480-483, 1980. Kaneshiro S, Nakajima T, Yoshikawa Y, Iwasaki H, Tokiwa N: The postoperative maxillary cyst: report of 7 I cases. J Oral Surg 39: 191-198, 1981. Gregory GT, Shafer WG: Surgical ciliated cysts of the maxilla: report of cases. J Oral Surg 16: 251-253, 1958. Bela1 A: Mucocele of the maxillary sinus. J Laryngol Otol 65: 286-288, 195 I. Eigler G: ijber die Entstehung von Mucocelen in operierten Kieferhohlen. H N 0 4: 103-106, 1954. Mennig H: Zur Pathogenese der kieferhiihlen Mucocelen. Arch Ohren-Nasen-Kehlkopth 196: 465-468, 1956.
Oral November,
Surg. 1986
18. Wirth G: Muko-Pyo-Zelen der Kieferhiihle. Monatsschr Ohrenheilkd 98: 243-248. 1962. 19. Brejcha M, Pihrt J: Zmey v. Celistnisch Dutinach po Operaci podle Caldwell Luca. Acta Univ Carol Med 9: 225. 1963. 20. Straube CH: Ein Beitrag zur postoperativen Kieferholenmukozele. Dtsch Stomatol 16: 269-274, 1966. 2 1. Ristow W: Riintgenologische Befunde nach Kieferholenoperationen. Z Laryngol Rhino1 48: 842, 1969. 22. Noyek AM, Zimol J: Radiology of the maxillary sinus after Caldwell-Luc surgery. Otolaryngol Clin North Am 9: I35 151, 1976. 23. Gardner DG: Pseudocysts and retention cysts of the maxillary sinus. ORAL SURG ORAL MED ORAL PATHOI. 58: 561-567, 1984. 24. Pindborg JJ, Kramer IR, Torloni H: Histological typing of odontogenic tumours; jaw cysts and allied lesions, Geneva, 1972, World Health Organization, pp. 39-42. 25. Psenner L: Die Riientgendiagnostik der Nase, der Nasenncbenhiilen und des Epipharynx; Handbuch der Meizinischen Radiologie, ed. I, Heidelberg, 1963, Springer-Verlag, pp. 203-211. 26. Manasse P: Die pathologische Anatomie dei Nebenholeneiterungen. H N 0 4: 473-488, 1923. Reprint requests to: Dr. Hirotsugu Yamamoto Pathology Section, Central Laboratories Nihon University School of Dentistry at Matsudo 2-870-l) Sakaecho-Nishi, Matsudo Chiba 271, Japan
Takagi, D.D.S., Ph.D.,**
PATHOLOGYSECTION,CENTRALLABORATORlESOFNlHON UNlVERSlTYSCHOOLOFDENTlSTRYAl MATSUDO,ANDDEPARTMENTOFORALPATHOLOGY,TOKYOMEDlCALANDDENTALUNlVERSlTY Sixty cases of the postoperative maxillary cyst were studied clinicopathologically. The cysts accounted for 19.5% of all oral cystic lesions. Most of the patients were in their 20s and 30s at the time of diagnosis, and the postoperative duration was between 10 and 49 years. Radiographically, most cases revealed a unilocular cystic lesion. In two thirds of the cases, the lesion occupied more than half the volume of the maxillary sinus while the remaining one third of the cases revealed more limited lesions of the sinus. Histopathologically. cuboidal, squamous, and mixed epithelial cyst linings were observed, although the basic epithelial lining was the ciliated columnar type. Epithelial dysplasia was found in two cases. The cysts near the nasal cavity may originate from regenerated nasal mucosa, and the cysts that are located at a distance from the nasal cavity may be lined with epithelium derived from residual mucosa of the sinus entrapped during surgery to relieve sinusitis. (ORAL SURG. ORAL MED. ORAL PATHOL. 62544-548,
1986)
T
he postoperative maxillary cyst occurs as a delayed complication following maxillary radical surgery.‘-3 Kubo4 reported the first case in 1927. After that, he added three cases and termed them postoperative Wangenzyste in 1933.5 Since then, many caseshave been reported, mainly in the Japanese literature. They have been reported under several names including mucocele and postoperative paranasal cyst.6-‘3 In 1958, Gregory and ShaferI described these cystic lesions in the English literature as “surgical ciliated cysts of the maxilla.” Although the lesion is relatively common in Japan, it appears to occur less frequently elsewhere.‘-3s 6.I3The purpose of this article is to study the clinicopathologic features of 60 postoperative maxillary cysts. MATERIALS
AND METHODS
The case material consisted of 60 postoperative maxillary cysts, which were diagnosed from 1976 to 1981 at the Pathology Section, Central Laboratories, Nihon University School of Dentistry at Matsudo. All cases were confirmed by histologic examination of excised specimens. Following fixation with 10% *Assistant Professor of Clinical Pathology, Nihon University. **Associate Professor of Oral Pathology, Tokyo Medical and Dental University. 544
Table I. Sex and age distribution at diagnosis of postoperative maxillary cyst Age
Male
Female
Total cases
20-29 30-39 40-49 50-59 60-69 70-79 Total
5 15 8 1 0 1 30
3 13 10 2 2 A! 30
8 28 IX 3 2 _1. 60
neutral formalin, routine paraffin sections were made. They were stained with hematoxylin and eosin, periodic acid--Schiff (PAS), PAS-alcian blue (pH 2.5) alcian blue (pH 0.4, 1.O, 2.5) azan Mallory, PAM, and van Gieson stains. RESULTS
Sex and age distribution are shown in Table I. Of 60 patients, 30 were males and 30 were females. Most were in their 20s and 30s. No patients were younger than 20 years old. The mean age was 39.1 years, with a range of 21 to 72 years. The duration between the first surgical procedure and the time of
Postoperative
Volume Number
62 5
Table
II. Time between radical surgery and diagno-
maxillary
cyst
545
sis Years
No. of cases
o-9 IO-19 20-29 30-39 40-49
4 32 20 2 2
diagnosis of postoperative maxillary cyst is shown in Table II. For 87% of the patients, the duration ranged between 10 and 29 years, with a mean of 18.3 years. The shortest period was 4 years; the longest period was 49 years. Thirty-seven cases were from the right maxilla, while 23 were from the left. Most (93%) were unilocular cystic lesions, with only four cases reported as being multilocular. A study of the size and location of the cysts showed that 24 cases (40%) occupied half of the maxillary sinus (Fig. l), 19 cases were localized in the lower portion of the sinus, and 17 cases occupied the entire sinus. In 42 cases, the buccal cortical bone was present; in 18 cases it was not. Surrounding bone sclerosis was evident in at least a portion of the bony margin in 58% of the cysts, whereas in the remaining cases this condition was missing. Most cases were located in the molar and premolar regions. Macroscopically, most cysts exhibited a wall of variable thickness and primarily contained brown mutinous or, rarely, serous fluid (Fig. 2). Purulent fluid and cholesterol crystals were found in several cases. Microscopically, it could be seen that most cysts were lined with ciliated columnar, cuboidal, or squamous epithelium (Figs. 3, 4). The majority of the cysts were lined with ciliated columnar epithelium. With increased duration, however, there was an increase in the proportion of cuboidal, squamous, and mixed epithelia. Occasional goblet cells were evident within the columnar epithelium. In addition, atypical epithelial changes were observed in two cases; one exhibited moderate dysplasia, and the other exhibited severe dysplasia (Fig. 5). The basement membrane was thickened in several cases, especially in cases with connective tissue hyalinization. Changes in the connective tissue of the cysts included fibrosis associated with hyalinization, inflammatory cell infiltration, and edema (Figs. 3, 4). In early lesions, edema and an inflammatory cell infiltrate were frequent findings. Dilated nasal glands (sometimes with apocrine metaplasia), calci-
Fig. 1. Panoramic radiograph showing unicystic lesion in maxillary sinus with surrounding bone sclerosis above molar and premolar regions (arrow).
2. Macroscopically, exhibits thick cystic wall.
Fig.
complete enucleated lesion
fication, cholesterol granulomas, metaplastic bone formation, and capillary dilatation were also seen. DISCUSSION
The postoperative maxillary cyst is a common lesion in Japan, but it is relatively rare in European countries and America. However, reports of similar lesions are found in several articles from these countries. BelaP described the first case of this entity in a 30-year-old woman. There have also been other reports, under several names, from different countries.‘4* ‘6-22 Recently, Gardner23 attempted to clarify the nature of the dome-shaped pseudocysts and retention cysts of the maxillary sinus. These two cysts are supposed to be different from the postoperative maxillary cyst. The pseudocyst of the maxillary sinus is composed of a cavity surrounded by a dense,
546
Yamamoto
and Takagi
Oral November,
Surg. 1986
Fig. 3. Microscopically, inner surface of cyst is lined with ciliated columnar and cuboidal epithelia with fibrosis, inflammatory cell infiltration, and cholesterol crystal slits. Lm. Lumen. (Hematoxylin and eosin X 100.) stain. Magnification,
Fig. 4. Inner surface of cyst is covered with metaplastic squamous epithelium hyalinization. Lm, Lumen. (Hematoxylin and eosin stain. Magnification, X 260.)
layer of fibrous connective tissue beneath the sinus mucosa, with no glands or ducts and containing inflammatory exudates. The retention cyst consists of a pseudostratified columnar epitheliurn-lined cavity, which is produced by partial blockage of the duct of seromucinous glands of the sinus, resulting in dilatation of the duct into a cystic structure. On the other hand, the postoperative maxillary cyst is lined with ciliated, cuboidal, or squamous epithelium and supported with hyslinized connective tissue. compact
with
fibrosis
and
In our hospital the postoperative maxillary cyst accounted for 19.5% of all oral cystic lesions. There were 307 cases of oral cystic lesions, which consisted of 178 odontogenic cysts and 129 nonodontogenic cysts. Therefore, the incidence of the postoperative maxillary cyst within the latter was 46.5%, which was the most common form of nonodontogenic cyst. Ito and co-workers’ and Manba9 reported a 23.6% and a 20.3% incidence of this lesion, respectively. Thus, the postoperative maxillary cyst is one of the most often encountered nonodontogenic cysts in
Volume Number
Postoperative
62 5
Fig.
5. Marked
epithelial
dysplasia. (Hematoxylin
Japan. Although the postoperative maxillary cyst was not described in Histological Typing of Odontogenic Tumours by the World Health Organization,24 this pathologic concept had been accepted as a distinct entity. Most patients were diagnosed as having a postoperative maxillary cyst in their 20s and 30s and had undergone radical maxillary surgery in their first two decades of life. For the diagnosis of postoperative maxillary cyst, it is important to bear in mind the history of previous maxillary surgery. Radiographically, most of our cases appeared as unilocular cystic lesion occupying half of the maxillary sinus, but some were localized or diffuse, and they involved the premolar and molar regions, as reported by others.‘) A zone of sclerosis surrounding the cyst was found in 58% of all cases. Tachikawa’O and Kaneshiro and colleaguesi reported an incidence of 66.7% and 68%, respectively, while Ohba’s group’* stated that this sclerotic zone was less frequently observed. PsennerZ5 indicated that early lesions were radiographically inconspicuous, whereas older lesions were readily apparent. Although the most common epithelium lining the cyst was of the ciliated columnar type, cuboidal, squamous, and mixed epithelial types were also frequently seen. Tachikawa’O also reported a 41% incidence of squamous metaplasia in the epithelia of the cysts. Manasse26 stated that metaplasia was often present in such cases, especially in areas of fibrosis and granuloma formation. Squamous metaplasia and the transition into cuboidal cells represents a regressive alteration. These changes may be caused by various types of chronic stimulation or inflammation.
and eosin stain. Magnification,
maxillary
X
cyst
547
800.)
The atypical epithelial changes that may occur in this cyst have not been described previously. We observed moderate to severe dysplasia in two cases. Several hypotheses have been proposed to explain the pathogenesis of the postoperative maxillary cyst. Kubo4s5 suggested two theories: (1) that the cyst might be caused by residual mucosa of the maxillary sinus being trapped in the wound resulting from a surgical procedure for treatment of sinusitis and (2) it might be caused by the retention of tissue fluid or blood forming a tissue space or sinus after the operation. Imai6 proposed that the cyst also might originate from regenerating mucosa within the sinus derived from the nasal cavity. In the present study, two thirds of the cases showed occupation of all or half of the maxillary sinus near the nasal cavity, and one third were localized to the lower portion of the sinus at a distance from the nasal cavity. The postoperative maxillary cyst is a form of retention cyst and occurs during the healing process after radical surgery for treatment of sinusitis. Therefore, cysts near the nasal cavity may arise from regenerated mucosa of the sinus or from the nasal mucosa, whereas cysts that are located at a distance from the nasal cavity may arise from residual mucosa of the sinus entrapped during surgery. REFERENCES 1. Shafer WG, Hine MY, Levy BM: A textbook of oral pathology, ed. 4, Philadelphia, 1983, W.B. Saunders Company, p. 545. 2. Van der Waal I.: Dental pathology slide seminar, ed. 3, Transactions of the IX European Congress of Pathology in Hamburg, 1983. 3. Lucas RB: Pathology of tumours of the oral tissues, ed. 4, Edinburgh, 1984, Churchill Livingstone, p. 382.
548 Yamamoto and Takagi
9.
10. 11.
12. 13.
14. 15. 16. 17.
Kubo I: A buccal cyst occurred after a radical operation of the maxillary sinus. Z Otol Tokyo 33: 896-897, 1927. Kubo I: Postoperative Wangenzyste. Z Otol Tokyo 39: 1831-1845, 1933. Imai T: Mucocele of the maxillary sinus after radical operation for sinusitis. Z Otol Tokyo 39: 723-735, 1933. Ito H: Clinicostatistical study of jaw cysts. J Jpn Stomatol Sot 18: 241, 1969. Kudo K, Fujioka Y, Ohashi Y: Clinicopathological study of postoperative maxillary cysts. J Jpn Stomatol Sot 21: 250257, 1972. Manba M: Clinical statistical observation of cysts of the oral region during the last five years. Niigata Dent J 4: 17-26, 1974. Tachikawa J: Clinicopathological study of postoperative maxillary cysts, Shika Gakuho 75: 1117-l 142, 1975. Onodera A, Sato M, Takahashi T: Electron microscopic studies of the postoperative maxillary cyst. Jpn J Otol 81: 918-925, 1978. Ohba T, Yang R, Chen C, Uneoka M: Postoperative maxillary cyst. Int J Oral Surg 9: 480-483, 1980. Kaneshiro S, Nakajima T, Yoshikawa Y, Iwasaki H, Tokiwa N: The postoperative maxillary cyst: report of 7 I cases. J Oral Surg 39: 191-198, 1981. Gregory GT, Shafer WG: Surgical ciliated cysts of the maxilla: report of cases. J Oral Surg 16: 251-253, 1958. Bela1 A: Mucocele of the maxillary sinus. J Laryngol Otol 65: 286-288, 195 I. Eigler G: ijber die Entstehung von Mucocelen in operierten Kieferhohlen. H N 0 4: 103-106, 1954. Mennig H: Zur Pathogenese der kieferhiihlen Mucocelen. Arch Ohren-Nasen-Kehlkopth 196: 465-468, 1956.
Oral November,
Surg. 1986
18. Wirth G: Muko-Pyo-Zelen der Kieferhiihle. Monatsschr Ohrenheilkd 98: 243-248. 1962. 19. Brejcha M, Pihrt J: Zmey v. Celistnisch Dutinach po Operaci podle Caldwell Luca. Acta Univ Carol Med 9: 225. 1963. 20. Straube CH: Ein Beitrag zur postoperativen Kieferholenmukozele. Dtsch Stomatol 16: 269-274, 1966. 2 1. Ristow W: Riintgenologische Befunde nach Kieferholenoperationen. Z Laryngol Rhino1 48: 842, 1969. 22. Noyek AM, Zimol J: Radiology of the maxillary sinus after Caldwell-Luc surgery. Otolaryngol Clin North Am 9: I35 151, 1976. 23. Gardner DG: Pseudocysts and retention cysts of the maxillary sinus. ORAL SURG ORAL MED ORAL PATHOI. 58: 561-567, 1984. 24. Pindborg JJ, Kramer IR, Torloni H: Histological typing of odontogenic tumours; jaw cysts and allied lesions, Geneva, 1972, World Health Organization, pp. 39-42. 25. Psenner L: Die Riientgendiagnostik der Nase, der Nasenncbenhiilen und des Epipharynx; Handbuch der Meizinischen Radiologie, ed. I, Heidelberg, 1963, Springer-Verlag, pp. 203-211. 26. Manasse P: Die pathologische Anatomie dei Nebenholeneiterungen. H N 0 4: 473-488, 1923. Reprint requests to: Dr. Hirotsugu Yamamoto Pathology Section, Central Laboratories Nihon University School of Dentistry at Matsudo 2-870-l) Sakaecho-Nishi, Matsudo Chiba 271, Japan