ci Yoshifumi Tajima, DDS,a Satoshi Yokose, &)I~S,~ Eiichi Sakamoto, DDS,’ Yoshiro Yamamoto, DDS,d and Nobuo Utsumi, DDS,e Saitama, Japan MEIKAI

UNIVERSITY

An unusual odontogenic odontogenic (0~

SCHOOL

OF DENTISTRY

case of an ameioblastoma with adenoid-cribriform features arising in calcifying cyst is reported. A possible relationship between this peculiar variant of calcifying cyst and a conventional ameloblastoma is discussed.

SURG ORAL MED ORAL PATHOL

1992;74:776-9)

he calcifying odontogenic cyst (COC) was first characterized by Gorlin et al.‘, 2 as a distinct type of odontogenic cyst that may occur both as an intraosseous (central) lesion and as a soft tissue (peripheral) lesion. In many respects, however, the designation of “cyst” for this lesion is not entirely ap-

propriate, because a significant number of cases present as a solid mass without gross or microscopic features of a cyst.3 In a recent review and analysis of the clinical, radiographic, and histomorphologic features of 2 15 cases of central COC, Buchner4 found only four ac-

Fig. 1. Panoramic radiograph showing large unilocular

ceptable cases representing the neoplastic (solid) Hong et a1.5 identified as a type. Furthermore,

radiolucency at midline region of mandible mass (arrows) at cystic margin.

with radiopaque

neoplasm 13 cases of 92 COCs from the files of the Armed Forces Institute of Pathology. In these articles, however, the criteria for deciding whether a given central (intraosseous) lesion is a cyst or neo-

revealed that the cyst extended to the premolar regions bilaterally and contained a small radiopaque mass on the right

plasm appeared somewhat ill defined. We report a case of ameloblastoma arising in COC

side (Fig. 1). Root resorption of the anterior teeth was also observed. Intraorally a slight enlargement of the overlying gingiva was seen, but the mucosa was normal in color. Gross examination of the submitted specimen revealed a tan cystic structure (3.3 x 2.2 cm) that contained a hard

(ameloblastoma

ex COC). Our discussion focuses on

the possible relationship between this rare neoplastic variant of COC and a conventional ameloblastoma. CASEREPORT A 35-year-old man had a well-demarcated in the mandibular symphysis. Radiographic “Associate Professor, Department of Oral bResearch Assistant, Department of Oral assistant Professor, Department of Oral dProfessor and Chairman, Department of eProfessor and Chairman, Department of l/14/38125

cystic lesion examination

Pathology. Patho!ogy.

Surgery. Oral

Surgery.

Oral Pathology.

object in the cystic wall. No evidence of an impacted tooth was noted. Follow-up examinations with radiographs showed normal healing with no recurrence of the lesion after 5 years. Microscopic sections exhibited a thick-walled cystic structure with resorption of the overlying alveolar bone and the apex of an incisor tooth (Fig. 2). The cyst wall was lined by low cuboidal to flattened squamous-type epithelial cells containing small and oval basophilic nuclei. Extending from this lining was an arrangement of cuboidal basophilic (hyperchromatic) cells with occasional stellate reticulum-like

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in calcifying odontogenic cyst

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Fig. 2. Low-power view of cystic lesion. Areas of epithelial proliferation, forming cords and islands, are seen at mural surface and in thick fibrous wall of cyst. Root resorption of incisor tooth by expansile cystic structure is evident. (Hematoxylin-eosin stain; original magnification, X7.)

Fig. 3. Islands of ameloblastomatous epithelial component that exhibit microcystic configurations with adenoid cribriform pattern. (Hematoxylin-eosin stain; original magnification, X100.) Inset, Rectangular area of epithelial lining demonstrating polarized columnar basal cell layer with cytoplasmic vacuolization. (Hematoxylin-eosin stain; original magnification, x280.) cellsthat frequently formed distended microcystic spacesor pseudocysts(Figs. 2 and 3). The pseudocystswere lined by cuboidal cells yielding an adenoid cribriform pattern. The intramural infiltration by this ameloblastic epithelial component was evident (Fig. 2). The detached epithelial nests within the fibrous cyst wall contained peripheral palisaded basaloid cells with nuclear polarization (Fig. 3). Clumps of ghost cellsand the formation of dentinoid material were also noted (Figs. 4 and 5). These “hybrid” neoplastic components were supported by a thick fibrous connective tissue stroma that exhibited very low cellularity. The initial diag-

nosiswas an ameloblastomatous proliferating type of COC that may fit into the category suggestedby Praetorius et al6 However, this diagnosis was reevaluated, and a final diagnosisof an ameloblastoma ex COC was made, on the basis of the histopathologic criteria proposed by Vickers and Gorlin.7 DISCUSSION The COC presents a wide range of histologic features. The lesion is occasionally associated with

798

Tajima et al.

Fig. 4. Area showing ameloblastomatous dentinoid material (ON). (Hematoxylin-eosin

proliferation together with presence of ghost cells iGC) and stain; original magnification, x 100.)

Fig. 5. Ameloblastomatous epithelium with small basophilic nuclei, some of which embrace ghost ceils, in close proximity to dentin&d material. (Hematoxylin-eosin stain, original magnification, X 1SO.) odontomas and other odontogenlc tumors such as ameloblastoma, ameloblastic fibroma, and ameloblastic fibro-odontoma.8 The simple unicystic type of COC seldom presents a problem in differential diagnosis, but classifying the disease may be difficult when elements resembling other odontogenic tumors are present.3 The neoplastic COCs are a rare and controversial group. With regard to the histogenesis of the COG, Praetorius et al.6 suggested that the lesion actually includes two entities: a cyst and a neoplasm. The authors termed the true neoplastic counterpart of the COC dentinogenic ghost cell tumor, and several ex-

amples of this unique odontogenic lesion, some of which were termed epithelial odontogenic ghost cell tumor (EOGT), have been reported.9-11 However, Hong et a1.5 recently suggested a modified classification because of the difficulty in placing some of 92 lesions of the COC into the categories designated by Praetorius et a1.6According to Hong et a1.,s The neoplastic COCs consist of ameloblastoma ex COC, peripheral EOGT, and central EOGT. In discussing the ameloblastoma ex CO@, Hong et aL5 identified only two examples of 13 cases subsumed under the neoplastic type of COC. These authors indicated that ameloblastoma ex COC could be differ-

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entiated from amelloblastomatous COC by the histopathologic criteria of early ameloblastoma suggested by Vickers and Gorlin,7 the lack of ghost cells and calcification in the transformed ameloblastoma areas, and extraluminal growth. In our case, however, one can easily appreciate the presence of ghost cells and juxtaepithelial dentinoid in the ameloblastomatous element. It appears that these findings may not entirely fit into the category of ameloblastoma ex COC proposed by Hong et a1.5 We believe that the presence or absence of ghost cells and dysplastic dentin reflects the variation in productive (or indltctive) potentiality of -the o’dontogenic epithelium. In this respect Waldron3 pointed out that neoplastic and hamartomatous aberrations of odontogenesis can occur in any stage of the developmental process. We believe that emphasis should instead be focused on the growth pattern of the ameloblastomatous area in accordance with the criteria for early ameloblastoma as proposed by Vickers and Gorlin.7 There may be some argument on the differential diagnosis with our present case. Some investigators may prefer the diagnosis of an EOGT. In fact, the EOGTs exhibit some similarities to our case with regard to the presence of ghost cells and juxtaepithelial dentinoid. As Hong et a1.5 indicated, however, the ameloblastomatous epithelium in EOGTs does not completely fulfill the criteria for early ameloblastoma proposed by Vickers and Gorlin.7 Above all, the intraosseous EOGT has an uncertain behavior because of the few known cases, including a malignant counterpart. lo, l2 The most important question to be considered in ameloblastoma ex COC is whether the lesion is a variant of COC or should be regarded as a subtype of ameloblastoma. Shlear8 stated .that the term dentinoameloblastoma may be appropriate for the neoplastic variant of COC. This term implies that the lesion is an ameloblastoma. In fact, the ameloblastomatous area seen in our case, manifesting a rather unusual growth pattern with adenoid-type features, showed a similarity to the illustrations of Fig. 2 within Gardner’s article l3 about unicystic ameloblastoma. However, there have been a considerable number of reports of amelobla.stoma arising from a variety of odontogenic cysts.3, *j I4 Therefore it is not surprising that the cyst-lining epithelium of COCs can be transformed into a true ameloblastoma that may fulfill the criteria of Vickers and Gorlin.7 Whether ameloblastoma ex COC should be classified as a subtype of

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ameloblastoma or as a subtype of COC may be open to argument. Buchner4 suggested that if the COC is associated with an ameloblastoma, its behavior and prognosis will be that of an ameloblastoma, not of a cot. We are grateful to Drs. Charles A. Waldron, Professor Emeritus, Emory University School of Postgraduate Dentistry, and Brad W. Neville, Professor, Medical University of South Carolina, for their valuable advice in preparing the manuscript. REFERENCES 1. Gorlin RJ, Pindborg JJ, Clausen FP, Vickers RA. The calcifying odontogenic cyst: a possible analogue of the cutaneous calcifying epithelioma of Malherbe-ap analysis of fifteen ~~~~~.O~~LSURGORALMEDO~LPATHOL 1962;15:1235-43. 2. Gorlin RJ, Pindborg JJ, Redman RS, Williamson JJ, Hansen LS. The calcifying odontogenic cyst: a new entity and possible analogue of the cutaneous calcifying epithelioma of Malherbe. Cancer 1964;17:723-9. 3. Waldron CA. Odontogenic tumors and selected jaw cysts. In: Gnepp DR, ed. Pathology of the head and neck: contemporary issues in surgical pathology; vol 10, New York: Churchill Livingstone, 1988;403-58. 4. Buchner A. The central (intraosseous) calcifying odontogenic cyst: an analysis of 215 cases. J Oral Maxillofac Surg 1991; 49:330-9. 5. Hong SP, Ellis GL, Hartman KS. Calcifying odontogenic cyst: a review of ninety-two cases with reevaluation of their nature as cysts or neoplasms, the nature of ghost cells, and subclassification. ORALSURGORAL MEDORALPATHOL 1991;72:5664. 6. Praetorius F, Hj#rting-Hansen E, Gorlin RJ, Vickers RA. Calcifying odontogenic cyst: range, variations and neoplastic potential. Acta Odontol Stand 1981;39:227-40. 7. Vickers RA, Gorlin RJ. Ameloblastoma: delineation of early bistopathologic features of neoplasia. Cancer 1970;26:699710. 8. Shear M. Cysts of the jaws: recent advances. J Oral Path01 1985;14:43-59. 9. Tajima Y, Ohno J, Utsumi N. The dentinogenic ghost cell tumor. J Oral Path01 1986;15:359-62. 10. Ellis GL, Shmookler BM. Aggressive (malignant?) epithelial odontogenic ghost cell tumor. ORAL SURG ORAL MED ORAL PATHOL 1986;61:471-8. 11. Giinham 8, Sengiin 0, Celasun B. Epithelial odontogenic ghost cell tumor: report of a case. J Oral Maxillofac Surg 1989;47:864-7. 12. Grodjesk JE, Dolinsky HB, Schneider LC, Dolinsky EH, Doyle JL. Odontogenic ghost cell carcinoma. ORAL SURG ORALMEDORALPATHOL 1987;63:576-81. 13. Gardner DG. Plexiform unicystic ameloblastoma: a diagnostic problem in dentigerous cysts. Cancer 1981;47:1358-63. 14. Holmlund A, Anneroth G, Lundquist G, Nordenram A. Ameloblastomas originating from odontogenic cysts. J Oral Path01 Med 1991;20:318-21. Reprint requests: Yoshifumi Tajima, DDS Department of Oral Pathology Meikai University School of Dentistry Sakado, Saitama 350-02, Japan

Ameloblastoma arising in calcifying odontogenic cyst. Report of a case.

An unusual case of an ameloblastoma with adenoid-cribriform features arising in calcifying odontogenic cyst is reported. A possible relationship betwe...
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