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Calcifying odontogenic cyst: Case report and review of literature
637
EL-BEIALY, EL-MOFrY, AND REFAI
vation, regardless of the presence or" absence of arthritis, abdominal pain, or other systemic symptoms. Gingival biopsy to assess the presence of vasculitis as well as a trial of oral steroids should be considered. Gingivitis, gingival petechiae, and mandibular pain may be a rare manifestation of active HSP, and may suggest early disease reactivation. Acknowledgment The technical and professional assistance of Dr Vishnu Reddy, Department of Pathology, in the preparation and review of the dermatopathological photomicrographs is greatly appreciated.
References I. Schaller IG, Szer IS: Systemic lupus erythematosus, der-
matomyositis, scleroderma, and vasculitis in childhood, in Textbook of Rheumatology (ed 3). Philadelphia, PA, Saunders, 1989, pp 1340-1341 2. Smith MD, Bellome1: Henoch-Schonlein purpura: Report of a case. 1 Oral Surg 38:377, 1980 3. Heng MCY: Henoch-Schonlein purpura. Br 1 Dermatol 112:235, 1985
4. Cream 11, Gumpel JM, Peachey RDG: Schonlein-Henoch purpura in the adult. Q 1 Med 39:461, 1970 5. Bym lR, Firtzsgerald IF, Northway ID, et al: Unusual manifestations of Henoch-Schonlein syndrome. Am 1 Dis Child 130:1335, 1976 6. Waldo FB: Is Henoch-Schonlein purpura the systemic form of IgA nephropathy? Am 1 Kidney Dis 12:373, 1988 7. Giangiacome 1, Tsai CC: Dermal and glomerular deposition of IgA in anaphylactoid purpura. Am 1 Dis Child 13:981, 1977 8. Evans Dl, Williams DG, Peters DK, et al: Glomerular deposition of properidin in Henoch-Schonlein syndrome and idiopathic focal nephritis. Br Med 1 3:326, 1973 9. Garcia-Fuentes M, Chantler C, Williams DO: Cryoglobulinemia in Henoch-Schonlein purpura. Br Med J 2:163, 1977 10. Kauffman RH, Herrman WA, Meyer CILM, et al: Circulating immune complexes in Henoch-Schonlein purpura: A longitudinal study of relationship to disease activity and vascular deposition of IgA. Am 1 Med 69:859, 1980 11. Meadow R: Schonlein-Henoch syndrome. Arch Dis Child 54:822, 1979 12. Saulsbury F'T, Kesler RW: Thrombocytosis in HenochSchonlein purpura. Clin Pediatr 22:185, 1983 13. Winter HS: Steroid effects on the course of abdominal pain " in children with Henoch-Schonlein purpura. Pediatrics 79:1018, 1987 14. Roth DA, Wilz DR, Theil GB: Schonlein-Henoch syndrome in adults. Q 1 Med 55:145, 1985
J Oral Maxillofac Surg
48:637-1540.1990
Calcifying Odontogenic Cyst: Case Report and Review of Literature RAGAB RADWAN EL-BEIALY, DDS,* SHERIF EL-MOFTY, PHD,t AND HAMIDA REFAI, MOSt The calcifying odontogenic cyst is a rare lesion having features of both a cyst and solid neoplasm. 1 It was first described as a separate entity in 1962by Gorlin and his coworkers.i However, it had been previously reported under various names including cholesteatoma of the jaws and a strange variant of arneloblastoma.l'" The international histological classification of Received from the Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt. * Professor, Department of Oral Surgery. t Professor and Chairman, Department of Oral Surgery. Instructor, Department of Oral Surgery. Address correspondence and reprint requests to Dr Refai: Department of Oral Surgery, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt.
*
© 1990 American Association of Oral and Maxillofacial Surgeons 0278-2391/90/4806-0017$3.00/0
odontogenic tumors issued by the World Health Organization in 1971 5 defined the calcifying odontogenic cyst as "a non-neoplastic cystic lesion in which the epithelial lining shows a well-defined basal layer of columnar cells, an overlying layer that is often many cells thick and that may resemble stellate reticulum, and masses of 'ghost' epithelial cells that may be in the epithelial cyst lining or in the fibrous capsule. The 'ghost' epithelial cells may become calcified. Dysplastic dentine may be laid down next to the basal layer of the epithelium." This article analyzes the previously reported cases, which were found to be slightly less than 200, and reports an additional case. Report of a Case A 16-year-old boy was seen in the Oral Surgery Department, Faculty of Oral and Dental Medicine, Cairo Uni-
638 versity with a chief complaint of a swelling in the anterior region of the mandible. The swelling had been presented for approximately 1 year. The past medical history was noncontributory. Intraoral examination disclosed a large, smooth bonyhard swelling of the anterior region of the mandible, measuring approximately 7 x 6 x 4 ern, extending from the right canine to the left first molar, and causing expansion of both buccal and lingual cortical plates of bone. The lingual cortical plate was expanded for about 4 ern, elevated the tongue, and interfered with speech and swallowing. The swelling was covered with stretched, pale pink mucosa. Eggshell crackling was elicited on the buccal side only. There was displacement and mobility of the lower anterior teeth. Radiographic examination revealed a well-defined multilocular radiolucency causing displacement and resorption of the roots of the lower anterior teeth. The buccal and lingual cortical plates were very thin and expanded (Figs 1 and 2). Fluid aspirated from the lesion was blood tinged, and reddish brown in color. Cystic ameloblastoma was the provisional diagnosis. An incisional biopsy was performed under local anesthesia. On histologic examination, the cyst was lined by stratified squamous epithelium of varying thickness. The basal layer consisted of columnar cells, whose nuclei were generally well polarized, and an overlying layer of polyhedral, loosely arranged cells resembling stellate reticulum. Pale, eosinophilic, swollen cells that had lost their nuclei (ghost cells) were scattered within the epithelial lining. The connective tissue wall of the cyst was highly vascular, with the subepithelial zone containing a few discrete, concentric eosinophilic bodies which were thought to be dentinoid in nature. Calcification was not a prominent histologic feature (Figs 3-5). A diagnosis of calcifying odontogenic cyst was made. With the patient under general anesthesia, the cyst was enucleated and the related teeth were extracted. The postoperative course was uneventful. The cyst was processed in a manner similar to the biopsy specimen and the diagnosis ofa calcifying odontogenic cyst was confirmed. One year after operation the patient was free of pain and showed no clinical or radiographic evidence of recurrence (Fig 6).
FIGURE I. Preoperative radiograph shows multilocular radiolucent area of the anterior region of the mandible causing displacement of the related teeth.
CALCIFYING ODONTOGENIC CYST
FIGURE 2. Periapical view showing root resorption by the cyst.
Discussion
A review of the literature revealed the presence of slightly less than 200 published cases of calcifying odontogenic cyst. On analyzing the reported cases, the age of the patients ranged between 1 and 87 years; however, the lesion occurred most frequently in young adults. There was no sex predilection. The most common site of occurrence of the calcifying odontogenic cyst was the tooth-bearing area, without any particular predilection to either the maxilla or the mandible. However, most of the reported cases were located anterior to the molar area. The vast majority of the published cases were intraosseous. However, peripheral lesions were also reported.v" The clinical features of the calcifying odontogenic cyst are nonspecific. Swelling of variable consistency was the most common symptom. Pain was not a prominent feature, although it has been reported in several cases. 6 ,7 ,9 Asymptomatic lesions were also reported to be detected on routine dental examination.t-" The lesion was found to be relatively slow growing and may be present for several years before the patient seeks advice and treatment.
FIGURE 3. Photomicrograph of the lining of the calcifying odontogenic cyst showing intraepithelial ghost cell formation, a prominent low columnar basal cell layer , and subepithelial dentinoid formation. (Hematoxylin-eosin stain. Original magnification, x 150.)
EL-BEIALY, EL-MOFfY, AND REFAI
FIGURE 4. Photomicrograph of the epithelial lining of the calcifying odontogenic cyst showing the resemblance to the stellate reticulum. (Hematoxylin-eosin stain. Original magnification, x 150.)
On radiographic examination , calcifying odontogenic cyst has no characteristic features. The intraosseous cyst is essentially a destructive lesion, producing a unilocular or multilocular radiolucency. Irregular calcified bodies ranging from tiny flecks to large masses are usually scattered throughout the radiolucency. The cortical plates of bone are often thin and expanded, and may become perforated by the lesion, which usually causes displacement and root resorption of the adjacent teeth. The lesion may be associated with unerupted teeth or a complex odontoma.t'? Extraosseous lesions may cause superficial erosion of the underlying bone. All the reported cases fulfill the histologic characteristics of the calcifying odontogenic cyst that was described by the WHO committee on the histologic typing of tumors, jaw cysts, and allied lesions." However, histologic variations of this lesion have been described. Ameloblastoma-like proliferations and clear cell changes in the calcifying odontogenic cyst have been reported.2A.8.11.12 Also, .melanin pigmentation has been observed in several cases. 6.13- 16 Most of the lesions were treated conservatively by enucleation or local excision. When done thor-
639
FIGURE 5. Photomicrograph showing pale eosinophilic staining islands of "ghost" cells. (Hem ato xylin-eosin stain. Original magnification, x ISO.)
oughly, recurrence should not be anticipated. One case was treated initially by resection." Recurrences have been reported in several cases.8.t7.t8 The possibility of recurrence mandates follow-up of these cases. There is a controversy about the nature of calcifying odontogenic cyst. Since its first description, it has been considered a benign odontogenic cYSt. 2.19 Freedman et al? proposed the name "cystic calcifying odontogenic tumor" for this lesion because of
FIGURE 6. One-year postoperative radiograph showing no evidence of recurrence.
640
CALCIFYING ODONTOGENIC CYST
the resemblance of its biologic behavior to that of a benign odontogenic tumor rather than a cyst. On a comprehensive study of the histopathology of 16 cases of calcifying odontogenic cyst, Praetorius et al" concluded that the lesion contains two entities, a cyst and a neoplasm. The pathogenesis of the calcifying odontogenic cyst remains unknown. 10 Generally, it has been accepted as being derived from odontogenic epithelium. 2 ,20 However, a cyst of similar appearance within the parotid salivary gland has been reported. 14 An analysis of the reported cases of calcifying odontogenic cyst showed that the lesion has variable clinical, radiographic, and histologic features. As the clinical and radiographic features are nonspecific, the lesion must be differentiated from ameloblastoma, ameloblastic odontoma, ameloblastic fibro-odontoma, dentigerous cyst, and other odontogenic cysts. Calcifying odontogenic cyst has never been reported as a provisional diagnosis. A preoperative diagnosis based on an incisional biopsy is essential to avoid unnecessary radical surgery. The histopathology of the calcifying odontogenic cyst is now well established. Craniopharyngioma and calcifying epithelioma of Malherbe were reported to have histologic similarity to calcifying odontogenic cyst in the way that the epithelial cells undergo "ghost cell" degeneration and calcification. 2 •14 ,2 1 An ultrastructural study of the calcifications in the calcifying odontogenic cyst and odontomas revealed that the ghost cells represent degenerated epithelial cells and that the calcifications associated with epithelium of both lesions were found to be of three types: dystrophic, dysplastic enamel, and dysplastic dentine (or ccmentumj.F When the diagnosis of calcifying odontogenic cyst is confirmed, enucleation or local excision should be performed. The cure rates reported with these operations do not justify radical procedures to achieve clear surgical margins. Follow-up is highly recommended as there is a possibility of recurrence. On the basis of the histologic findings of the presented case, together with that of the other reported cases, it was concluded that the descriptive term calcifying odontogenic cyst is unsatisfactory, as not all the cases are cystic or calcified. Summary
A case of calcifying odontogenic cyst is presented. An analysis of the previously reported cases
indicates the variable clinical, radiographic and histopathologic features of the lesion. References I. Shafer WG, Hine MK, Levy BM: Textbook of Oral Pathology. Philadelphia, PA, Saunders, 1983, p 274 2. Gorlin RJ, Pindborg JJ, Clausen F, et al: The calcifying odontogenic cyst-A possible analogue of the cutaneous calcifying epithelioma of Malherbe. Oral Surg 15:1235, 1%2 3. Rywkind AW: Beitrag zur pathologie der cholesteatome. Virchows Arch Pathol 283:13, 1932 4. Thoma KH, Goldman HM: Odontogenic tumor classification based upon observation of epithelial, mesenchymal and mixed varieties. Am J Pathol 22:433, 1946 5. PindborgJJ, Kramer IRH, Torloni H: Histological Typing of Odontogenic Tumors, Jaw Cysts, and Allied Lesions. Geneva, Switzerland, World Health Organization, 1971 6. Abrams AM, Howell FV: The calcifying odontogenic cyst. Report of four cases. Oral Surg 25:594, 1%8 7. Freedman PD, Lumerman H, Gee JK: Calcifying odontogenic cyst. A review and analysis of seventy cases. Oral Surg 40:93, 1975 8. Praetorius F, Hjorting-Hansen E, Gorlin RJ, et al: Calcifying odontogenic cyst: Range, variations and neoplastic potential. Acta Odontol Scand 39:227, 1981 9. Keszler A, Guglielmotti MB: Calcifying odontogenic cyst associated with odontoma: Report of two cases. J Oral Maxillofac Surg 45:457, 1987 10. Altini M, Farman AG: The calcifying odontogenic cyst: Eight new cases and review of the literature. Oral Surg 40:751, 1975 II. Boss JH: A rare variant of ameloblastoma. Arch Pathol 68:299, 1959 12. Ng KH, Siar CH: Clear cell change in a calcifying odontogenic cyst. Oral Surg 60:417, 1985 13. Duckworth R, Seward GR: A melanotic ameloblastic odontoma. Oral Surg 19:73, 1%5 14. Gorlin RJ, Pindborg JJ, Redman RS, et al: The calcifying odontogenic cyst: A new entity and possible analogue of the cutaneous calcifying epithelioma of Malherbe. Cancer 17:723, 1964 15. Chandi SM, Simon GT: Calcifying odontogenic cyst: Report of two cases. Oral Surg 30:99, 1970 16. Soames JV: A pigmented calcifying odontogenic cyst. Oral Surg 53:395, 1982 17. Pullman SF, Seldin R: The calcifying odontogenic cyst: Report of a case. J Oral Surg 29:367, 1971 18. McGowan RH, Browne RM: The calcifying odontogenic cyst: A problem of preoperative diagnosis. Br J Oral Surg 20:203, 1982 19. Gold L: The keratinizing and calcifying odontogenic cyst. Oral Surg 16:1414, 1%3 20. Killey HC: Benign Cystic Lesions of the Jaws, Their Diagnosis and Treatment. Bristol, England, Wright, 1977, p 141 21. Arole G, Mosadomi A, Arian AH: Calcifying epithelioma of Malherbe (pilomatrixoma) of the cheek. J Oral Maxillofac Surg 41:121, 1983 22. Sapp JP, Gardner DG: An ultrastructural study of the calcifications in calcifying odontogenic cysts and odontomas. Oral Surg 44:754, 1977
EL-BEIALY, EL-MOFrY, AND REFAI
vation, regardless of the presence or" absence of arthritis, abdominal pain, or other systemic symptoms. Gingival biopsy to assess the presence of vasculitis as well as a trial of oral steroids should be considered. Gingivitis, gingival petechiae, and mandibular pain may be a rare manifestation of active HSP, and may suggest early disease reactivation. Acknowledgment The technical and professional assistance of Dr Vishnu Reddy, Department of Pathology, in the preparation and review of the dermatopathological photomicrographs is greatly appreciated.
References I. Schaller IG, Szer IS: Systemic lupus erythematosus, der-
matomyositis, scleroderma, and vasculitis in childhood, in Textbook of Rheumatology (ed 3). Philadelphia, PA, Saunders, 1989, pp 1340-1341 2. Smith MD, Bellome1: Henoch-Schonlein purpura: Report of a case. 1 Oral Surg 38:377, 1980 3. Heng MCY: Henoch-Schonlein purpura. Br 1 Dermatol 112:235, 1985
4. Cream 11, Gumpel JM, Peachey RDG: Schonlein-Henoch purpura in the adult. Q 1 Med 39:461, 1970 5. Bym lR, Firtzsgerald IF, Northway ID, et al: Unusual manifestations of Henoch-Schonlein syndrome. Am 1 Dis Child 130:1335, 1976 6. Waldo FB: Is Henoch-Schonlein purpura the systemic form of IgA nephropathy? Am 1 Kidney Dis 12:373, 1988 7. Giangiacome 1, Tsai CC: Dermal and glomerular deposition of IgA in anaphylactoid purpura. Am 1 Dis Child 13:981, 1977 8. Evans Dl, Williams DG, Peters DK, et al: Glomerular deposition of properidin in Henoch-Schonlein syndrome and idiopathic focal nephritis. Br Med 1 3:326, 1973 9. Garcia-Fuentes M, Chantler C, Williams DO: Cryoglobulinemia in Henoch-Schonlein purpura. Br Med J 2:163, 1977 10. Kauffman RH, Herrman WA, Meyer CILM, et al: Circulating immune complexes in Henoch-Schonlein purpura: A longitudinal study of relationship to disease activity and vascular deposition of IgA. Am 1 Med 69:859, 1980 11. Meadow R: Schonlein-Henoch syndrome. Arch Dis Child 54:822, 1979 12. Saulsbury F'T, Kesler RW: Thrombocytosis in HenochSchonlein purpura. Clin Pediatr 22:185, 1983 13. Winter HS: Steroid effects on the course of abdominal pain " in children with Henoch-Schonlein purpura. Pediatrics 79:1018, 1987 14. Roth DA, Wilz DR, Theil GB: Schonlein-Henoch syndrome in adults. Q 1 Med 55:145, 1985
J Oral Maxillofac Surg
48:637-1540.1990
Calcifying Odontogenic Cyst: Case Report and Review of Literature RAGAB RADWAN EL-BEIALY, DDS,* SHERIF EL-MOFTY, PHD,t AND HAMIDA REFAI, MOSt The calcifying odontogenic cyst is a rare lesion having features of both a cyst and solid neoplasm. 1 It was first described as a separate entity in 1962by Gorlin and his coworkers.i However, it had been previously reported under various names including cholesteatoma of the jaws and a strange variant of arneloblastoma.l'" The international histological classification of Received from the Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt. * Professor, Department of Oral Surgery. t Professor and Chairman, Department of Oral Surgery. Instructor, Department of Oral Surgery. Address correspondence and reprint requests to Dr Refai: Department of Oral Surgery, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt.
*
© 1990 American Association of Oral and Maxillofacial Surgeons 0278-2391/90/4806-0017$3.00/0
odontogenic tumors issued by the World Health Organization in 1971 5 defined the calcifying odontogenic cyst as "a non-neoplastic cystic lesion in which the epithelial lining shows a well-defined basal layer of columnar cells, an overlying layer that is often many cells thick and that may resemble stellate reticulum, and masses of 'ghost' epithelial cells that may be in the epithelial cyst lining or in the fibrous capsule. The 'ghost' epithelial cells may become calcified. Dysplastic dentine may be laid down next to the basal layer of the epithelium." This article analyzes the previously reported cases, which were found to be slightly less than 200, and reports an additional case. Report of a Case A 16-year-old boy was seen in the Oral Surgery Department, Faculty of Oral and Dental Medicine, Cairo Uni-
638 versity with a chief complaint of a swelling in the anterior region of the mandible. The swelling had been presented for approximately 1 year. The past medical history was noncontributory. Intraoral examination disclosed a large, smooth bonyhard swelling of the anterior region of the mandible, measuring approximately 7 x 6 x 4 ern, extending from the right canine to the left first molar, and causing expansion of both buccal and lingual cortical plates of bone. The lingual cortical plate was expanded for about 4 ern, elevated the tongue, and interfered with speech and swallowing. The swelling was covered with stretched, pale pink mucosa. Eggshell crackling was elicited on the buccal side only. There was displacement and mobility of the lower anterior teeth. Radiographic examination revealed a well-defined multilocular radiolucency causing displacement and resorption of the roots of the lower anterior teeth. The buccal and lingual cortical plates were very thin and expanded (Figs 1 and 2). Fluid aspirated from the lesion was blood tinged, and reddish brown in color. Cystic ameloblastoma was the provisional diagnosis. An incisional biopsy was performed under local anesthesia. On histologic examination, the cyst was lined by stratified squamous epithelium of varying thickness. The basal layer consisted of columnar cells, whose nuclei were generally well polarized, and an overlying layer of polyhedral, loosely arranged cells resembling stellate reticulum. Pale, eosinophilic, swollen cells that had lost their nuclei (ghost cells) were scattered within the epithelial lining. The connective tissue wall of the cyst was highly vascular, with the subepithelial zone containing a few discrete, concentric eosinophilic bodies which were thought to be dentinoid in nature. Calcification was not a prominent histologic feature (Figs 3-5). A diagnosis of calcifying odontogenic cyst was made. With the patient under general anesthesia, the cyst was enucleated and the related teeth were extracted. The postoperative course was uneventful. The cyst was processed in a manner similar to the biopsy specimen and the diagnosis ofa calcifying odontogenic cyst was confirmed. One year after operation the patient was free of pain and showed no clinical or radiographic evidence of recurrence (Fig 6).
FIGURE I. Preoperative radiograph shows multilocular radiolucent area of the anterior region of the mandible causing displacement of the related teeth.
CALCIFYING ODONTOGENIC CYST
FIGURE 2. Periapical view showing root resorption by the cyst.
Discussion
A review of the literature revealed the presence of slightly less than 200 published cases of calcifying odontogenic cyst. On analyzing the reported cases, the age of the patients ranged between 1 and 87 years; however, the lesion occurred most frequently in young adults. There was no sex predilection. The most common site of occurrence of the calcifying odontogenic cyst was the tooth-bearing area, without any particular predilection to either the maxilla or the mandible. However, most of the reported cases were located anterior to the molar area. The vast majority of the published cases were intraosseous. However, peripheral lesions were also reported.v" The clinical features of the calcifying odontogenic cyst are nonspecific. Swelling of variable consistency was the most common symptom. Pain was not a prominent feature, although it has been reported in several cases. 6 ,7 ,9 Asymptomatic lesions were also reported to be detected on routine dental examination.t-" The lesion was found to be relatively slow growing and may be present for several years before the patient seeks advice and treatment.
FIGURE 3. Photomicrograph of the lining of the calcifying odontogenic cyst showing intraepithelial ghost cell formation, a prominent low columnar basal cell layer , and subepithelial dentinoid formation. (Hematoxylin-eosin stain. Original magnification, x 150.)
EL-BEIALY, EL-MOFfY, AND REFAI
FIGURE 4. Photomicrograph of the epithelial lining of the calcifying odontogenic cyst showing the resemblance to the stellate reticulum. (Hematoxylin-eosin stain. Original magnification, x 150.)
On radiographic examination , calcifying odontogenic cyst has no characteristic features. The intraosseous cyst is essentially a destructive lesion, producing a unilocular or multilocular radiolucency. Irregular calcified bodies ranging from tiny flecks to large masses are usually scattered throughout the radiolucency. The cortical plates of bone are often thin and expanded, and may become perforated by the lesion, which usually causes displacement and root resorption of the adjacent teeth. The lesion may be associated with unerupted teeth or a complex odontoma.t'? Extraosseous lesions may cause superficial erosion of the underlying bone. All the reported cases fulfill the histologic characteristics of the calcifying odontogenic cyst that was described by the WHO committee on the histologic typing of tumors, jaw cysts, and allied lesions." However, histologic variations of this lesion have been described. Ameloblastoma-like proliferations and clear cell changes in the calcifying odontogenic cyst have been reported.2A.8.11.12 Also, .melanin pigmentation has been observed in several cases. 6.13- 16 Most of the lesions were treated conservatively by enucleation or local excision. When done thor-
639
FIGURE 5. Photomicrograph showing pale eosinophilic staining islands of "ghost" cells. (Hem ato xylin-eosin stain. Original magnification, x ISO.)
oughly, recurrence should not be anticipated. One case was treated initially by resection." Recurrences have been reported in several cases.8.t7.t8 The possibility of recurrence mandates follow-up of these cases. There is a controversy about the nature of calcifying odontogenic cyst. Since its first description, it has been considered a benign odontogenic cYSt. 2.19 Freedman et al? proposed the name "cystic calcifying odontogenic tumor" for this lesion because of
FIGURE 6. One-year postoperative radiograph showing no evidence of recurrence.
640
CALCIFYING ODONTOGENIC CYST
the resemblance of its biologic behavior to that of a benign odontogenic tumor rather than a cyst. On a comprehensive study of the histopathology of 16 cases of calcifying odontogenic cyst, Praetorius et al" concluded that the lesion contains two entities, a cyst and a neoplasm. The pathogenesis of the calcifying odontogenic cyst remains unknown. 10 Generally, it has been accepted as being derived from odontogenic epithelium. 2 ,20 However, a cyst of similar appearance within the parotid salivary gland has been reported. 14 An analysis of the reported cases of calcifying odontogenic cyst showed that the lesion has variable clinical, radiographic, and histologic features. As the clinical and radiographic features are nonspecific, the lesion must be differentiated from ameloblastoma, ameloblastic odontoma, ameloblastic fibro-odontoma, dentigerous cyst, and other odontogenic cysts. Calcifying odontogenic cyst has never been reported as a provisional diagnosis. A preoperative diagnosis based on an incisional biopsy is essential to avoid unnecessary radical surgery. The histopathology of the calcifying odontogenic cyst is now well established. Craniopharyngioma and calcifying epithelioma of Malherbe were reported to have histologic similarity to calcifying odontogenic cyst in the way that the epithelial cells undergo "ghost cell" degeneration and calcification. 2 •14 ,2 1 An ultrastructural study of the calcifications in the calcifying odontogenic cyst and odontomas revealed that the ghost cells represent degenerated epithelial cells and that the calcifications associated with epithelium of both lesions were found to be of three types: dystrophic, dysplastic enamel, and dysplastic dentine (or ccmentumj.F When the diagnosis of calcifying odontogenic cyst is confirmed, enucleation or local excision should be performed. The cure rates reported with these operations do not justify radical procedures to achieve clear surgical margins. Follow-up is highly recommended as there is a possibility of recurrence. On the basis of the histologic findings of the presented case, together with that of the other reported cases, it was concluded that the descriptive term calcifying odontogenic cyst is unsatisfactory, as not all the cases are cystic or calcified. Summary
A case of calcifying odontogenic cyst is presented. An analysis of the previously reported cases
indicates the variable clinical, radiographic and histopathologic features of the lesion. References I. Shafer WG, Hine MK, Levy BM: Textbook of Oral Pathology. Philadelphia, PA, Saunders, 1983, p 274 2. Gorlin RJ, Pindborg JJ, Clausen F, et al: The calcifying odontogenic cyst-A possible analogue of the cutaneous calcifying epithelioma of Malherbe. Oral Surg 15:1235, 1%2 3. Rywkind AW: Beitrag zur pathologie der cholesteatome. Virchows Arch Pathol 283:13, 1932 4. Thoma KH, Goldman HM: Odontogenic tumor classification based upon observation of epithelial, mesenchymal and mixed varieties. Am J Pathol 22:433, 1946 5. PindborgJJ, Kramer IRH, Torloni H: Histological Typing of Odontogenic Tumors, Jaw Cysts, and Allied Lesions. Geneva, Switzerland, World Health Organization, 1971 6. Abrams AM, Howell FV: The calcifying odontogenic cyst. Report of four cases. Oral Surg 25:594, 1%8 7. Freedman PD, Lumerman H, Gee JK: Calcifying odontogenic cyst. A review and analysis of seventy cases. Oral Surg 40:93, 1975 8. Praetorius F, Hjorting-Hansen E, Gorlin RJ, et al: Calcifying odontogenic cyst: Range, variations and neoplastic potential. Acta Odontol Scand 39:227, 1981 9. Keszler A, Guglielmotti MB: Calcifying odontogenic cyst associated with odontoma: Report of two cases. J Oral Maxillofac Surg 45:457, 1987 10. Altini M, Farman AG: The calcifying odontogenic cyst: Eight new cases and review of the literature. Oral Surg 40:751, 1975 II. Boss JH: A rare variant of ameloblastoma. Arch Pathol 68:299, 1959 12. Ng KH, Siar CH: Clear cell change in a calcifying odontogenic cyst. Oral Surg 60:417, 1985 13. Duckworth R, Seward GR: A melanotic ameloblastic odontoma. Oral Surg 19:73, 1%5 14. Gorlin RJ, Pindborg JJ, Redman RS, et al: The calcifying odontogenic cyst: A new entity and possible analogue of the cutaneous calcifying epithelioma of Malherbe. Cancer 17:723, 1964 15. Chandi SM, Simon GT: Calcifying odontogenic cyst: Report of two cases. Oral Surg 30:99, 1970 16. Soames JV: A pigmented calcifying odontogenic cyst. Oral Surg 53:395, 1982 17. Pullman SF, Seldin R: The calcifying odontogenic cyst: Report of a case. J Oral Surg 29:367, 1971 18. McGowan RH, Browne RM: The calcifying odontogenic cyst: A problem of preoperative diagnosis. Br J Oral Surg 20:203, 1982 19. Gold L: The keratinizing and calcifying odontogenic cyst. Oral Surg 16:1414, 1%3 20. Killey HC: Benign Cystic Lesions of the Jaws, Their Diagnosis and Treatment. Bristol, England, Wright, 1977, p 141 21. Arole G, Mosadomi A, Arian AH: Calcifying epithelioma of Malherbe (pilomatrixoma) of the cheek. J Oral Maxillofac Surg 41:121, 1983 22. Sapp JP, Gardner DG: An ultrastructural study of the calcifications in calcifying odontogenic cysts and odontomas. Oral Surg 44:754, 1977