Clear-cell calcifying odontogenic tumor viewed relative to the Pindborg tumor Robert 0. Greer, Jr., D.D.S., Sc.D.,* and John F. Ricbrdsox, Xc.D.,*+ Denver, Colo., and Boston, &!a~.

D.D.S.,

UNIVERSITY

SCHOOL

OF

GRADUATE

OF

COLORADO

MEDICAL

CENTER

AND

BOSTON

UNIVERSITY

DENTISTRY

An unusual clear-cell odontogenic tumor with lesional calcification is described and prognostic implications of this and other atypical benign odontogenic tumors are discussed relative to a calcifying tumor of epithelial odontogenic origin with a known aggressive potential.

A

type of calcifying epithelial odontogenic tumor (CEOT) was first characterized by Pindborg’ in 1958 and is now recognized as a distinct entity by the World Health Organization.2 The growth potential and biologic behavior have been authoritatively stated to be similar to the ameloblastoma,3 indicating a probability of invasiveness and prediction of local recurrence if conservatively removed in an advanced developmental stage. However, confusion as to the exact nature of the process seems to exist. Some have suggested, in some cases, a less aggressive course,4 or a variable aggressiveness, sometimes similar to ameloblastoma,j and others consider the growth potential to be unclear.F It is not known to what extent interpretations of indolent behavior are based on follow-up of CEOT excised at a very early growth stage or, on the other hand, of related tumors of undefined (non-Pindborg) atypical histomorphology. The basic histologic pattern of CEOT (Pindborg), described as “characteristic” and “unique” by recent reviewers7, R whose reports maintained a histologic consistency with the original published observations, is one of sheets or masses of polyhedral epithelial cells with deeply eosinophilic cytoplasm supported by *Assistant Professor of Pathology and Chairman, University of Colorado Medical Center. **Associate Professor and Chairman, Department School of Graduate Dentistry.

Division of

of Oral Oral

Pathology

Pathology,

and Oncology, Boston

University

775

776

Greer

and Richardson

Fig. 1. Radiographic opaque nidus.

appearance

of lesion.

Note

the circumscribed

lucency

with

its

central

a scanty connective tissue stroma. Intercellular “bridging” is an often noted characteristic, and there may be a moderate amount of nuclear pleomorphism as well as considerable variation in chromaticity of individual cell nuclei. Foci of amorphous, faintly eosinophilfc cell product, as well as small round or irregular calcific aggregates, which may be massively coalescent and occasionally show a concentric ring phenomenon, are an invariable feature of the “classic” CEOT histopathology. Readily acceptable variations within this classification are generally minor departures from that described. A survey of twenty-three cases from the files of the Armed Forces Institute of Pathology with a discussion of variation was recently reported by Krolls and Pindborg.8 They commented on the diagnostic challenge of a “clear-cell” variant and found two such tumors in their series. It is significant to note that in both casts there were transition areas to an unequivocal Pindborg type of histology. Abrams and Howell” reported a single instance of clear-cell CEOT in a 1967 review of four tumors. In this case, also, a bimorphic cytoplasmic appearance was observed. The pathologist confronted with a clear-cell odontogenic tumor must consider clear cell types of salivary tissue neoplasms, metastatic hypernephroma, and glycogen-rich adenocarcinoma” in a differential microscopic diagnosis. The clinical, radiographic, and histologic findings of an unusual clear-cell tumor of odontogenic origin with lesional calcification arc presented. We are in basic disagreement with some who would perfunctorily assign this lesion to the Pindborg-CEOT category. CASE

REPORT

A 37-year-old white woman visited her dentist for routine dental care. A mandibular radiolucency was discovered between the right lateral incisor and the right cuspid. The patient was unaware of the lesion and could not document its onset. Medical history was noncontribu-

(‘lew-cell

cnlcifyiy~

odoxtogenic

Fig. a. Tumor composed of epithelial cell clusters with quantitative Scattered calcifications are noted. ences in cytoplasmic appearance. stain. Magnification, x100.)

tunaor

777

and qualitative differ(Hematoxylin and eosin

tory. The lesion was a well-circumscribed lucency that contained a central radiopaque nidus (Fig. 1). It was located entirely within bone; there was no evidence of expansion of the 1~~~x1 or lingual cortices, and the mucosa overlying the lesion was intact. The lesion was removed under local anesthesia. The tumor separated quite easily from the alveolar bone, and curettage of its cryptlike housing was performed. The patient’s 13.month postoperative course has been uneventful. Pathology

The surgical specimen consisted of a tan-pink soft-tissue nodule measuring 5 by 4 by 3 mm. with a smooth, glistening, nonulcerated external surface. The bisected specimen revealed a central irregular calcified mass. The specimen was decalcified and processed in a routine manner ; level sections were stained with hematoxylin and eosin. The tumor extended to the margins of the section. Serial sections of the tissue block revealed a proliferative process composed predominantly of clusters of polymorphic cells set in a variable ramifying stroma (Fig. 2). Individual tumor cells were large and irregularly ovoid, with cytoplasm finely granular, through loosely reticular, to clear, depending on degree of vacuolization. Cell borders were distinct only in the latter type. Most of the epithelial groups had a well-delineated organoid appearance (Fig. 3). There was some variation in nuclear size, but significant hyprrchromatism and pleomorphism were absent. PAS stain ~vvas negative for cells and strongly positive in precalcific matrix areas. The center of the lesion contained extensive calcific aggregates, with smaller diffusely distributed calcifications present peripherally. All concretions stained positively for calcium with a Van Kossa preparation and, with rare exceptions, appeared to arise from the mesenchymal component (Fig. 4). There were areas wherein tumor cells that closely abutted the periphery of a calcification and appeared to be due to a displacement process originating in thca stroma. Occasional small foci of faintly fil,rill:rr eosinophilic material of suggestirP stromal origin nerc~ dispersed within the tumor; holyever, no accumulations of the homogeneous “amyloid” t ype were noted. Staining with Congo red followed by polarization microscopy was negative.

DISCUSSION

That odontogenic tumors with the classic “Pindborg histology” have a potential for an aggressive infiltrative course is widely accepted. Perceptions relating

770

Fig. trichrome

Greer

and Richnrdson

3. Well-defined clear-cell groups stain. Magnification, x240.)

Fig. 4. Representative (Hematoxylin and eosin

of the variability stain. Magnification,

with

closely

of calcific x200.)

supportive

change

collagenous

stroma.

in the mesenchymal

(Masson

component.

to this position are based on clinical experience. An aggressive course in every case is disputed by some; apparently not all CEOTs observed have shown this trait and, even where invasiveness is demonstrated, the growth rate of the tumor may be prolonged. lo These considerations might also be applied to ameloblastoma. In order to provide meaningful correlates to the pathologist’s diagnosis of CEOT, the parameters of histologic appearance must be precisely defined. As the histologic pattern which served as the basis for the initial collection of cases by Pindborgl is unequivocally accepted and is adequately represented in most subon this histologic theme are presumptive sequent published reports, “variations”

Volume Number

42 6

Clear-cell

cnlcifying

odontogenic

tumor

779

unless definitive transition areas are observed. The three previously published cases of the clear-cell type of CEOT showed such areas. A multiphasic histology may, indeed, prove to have clinical implications. The cellular phase in the present case consists totally of clear-cell clusters in an organoid configuration with a closely supportive and well-organized collagenous stroma. The question of a functional significance to the presence and amount of calcification in typical CEOT was recently raised,‘, R and this insight may encourage retrospective evaluation of the clinical course. It may be that a relation of cellular pattern to clinical outcome will prove as productive. It is hoped that a reappraisal of histologic criteria in this category of tumor with a generally stated aggressive potential behavior will more definitively relate microscopic manifestations of cellular biology with the course of human disease. Calcifying tumors of odontogenic origin histologically quite unlike the Pindborg standard have been reported with an apparently limited’l or decidedI” state of aggressiveness. Individual and unique tissue formations in the odontogenic field, while benignly neoplastic, are ill used by compulsive subclassification. The Herberger.

authors

wish

to

acknowledge

the

clinical

management

of

this

case

by

Dr.

Joseph

REFERENCES 1. Pindborg, J. J.: A Calcifying Epithelial Odontogenic Tumor, Cancer 2: 838-43, 1958. Typing of Odontogenic 2. Pindborg, J. J., Kramer, I. R. A., and Torloni, H.: Histologic Tumors, Jaw Cysts and Allied Lesions, No. 5, International Histologic Classification of Tumors Series, Geneva, 1971, World Health Organization. 3. Shafer, 1%‘. G., Hine, M. K., and Levy, B. M.: A Textbook of Oral Pathology, ed. 3, Philadelphia, 1974, W. B. Saunders Company, p. 260. 4. Pindborg, J. J. : Personal communication, 1975. 5. Gorlin, R. J.: Odontogenic Tumors. In Gorlin, R. J., and Goldman, H. M., (editors) : Thoma’s Oral Pathologv. -“, St. Louis. 1970. The C. V. Mosbv Comaanv. D. 492. 6. Abrams, A. M., and Howell, F. V.‘: Calcifying Epithelial”Odon~oge&~ Tumor: Report of Four Cases, J. Am. Dent. Assoc. 74: 1231-1240, 1967. 7. Solomon, M. P., Vuletin, J. C., Pertschuk, D. O., Gormley, M. B., and Rosen, Y.: Calcifying Epithelial Odontogenic Tumors, ORAL SURG. 40: 522-529, 1975. 8. Krolls, 8. O., and Pindborg, J. J.: Calcifying Epithelial Odontogenic Tumor: A Survey of 23 Cases and Discussions of Histomorphologic Variations, Arch. Pathol. 98: 206-210, 1974. 9. Mohamed, A. H., and Cherrick, H. M.: Glycogen-Rich Adenocarcinoma of Minor Salivary Glands: A Light and Electron Microscopic Study, Cancer 36: 1057-1066, 1975. 10. Stimson, P. G., Luna, M. A., and Butler, J. J.: Seventeen-Year History of a Calcifying Epithebal Odontogenic (Pindborg) Tumor, ORAL SURG. 25: 204-208, 1968. 11. Richardson, J. F., Balogh, K., Merk, F., and Booth, D.: Pigmented Odontogenic Tumor of Jamhone: A Previously Underscribed Expression of Neoplastic Potential, Cancer 34: 1244-1251, 1974. 12. Mohamed, A. H:, and Waterhouse, J. P.: A Light and Electron Microscopic Study of an Atypical Calcifymg Odontogenic Tumor Containing “Amyloid,” J. Oral Pathol. 2: 150-164, 1973.

Reprint request to: Dr. Robert 0. Greer, Jr. Oral Pathology Laboratory, Box C285 School of Dentistry University of Colorado Medical Center Denver. Colo. 80262

Clear-cell calcifying odontogenic tumor viewed relative to the Pindborg tumor.

Clear-cell calcifying odontogenic tumor viewed relative to the Pindborg tumor Robert 0. Greer, Jr., D.D.S., Sc.D.,* and John F. Ricbrdsox, Xc.D.,*+ De...
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