Ultrastructural study of an odontogenic myxoma

Ultrastructural study of an odontogenic myxoma Lnwence

I. Goldblatt,

DEPARTMEST

D.D.S., M.S.D., Indinnnpolis,

OF ORAL PATHOLOGY,

INDIANA

Ittd.

UKIVERSITY

SCHOOL OF

DENTISTRY Ultrastructural study of an odontogenic mgxoma has revealed two basic types of tumor cells: secretory and nonsecretory. The secretory cell type is the principal tumor cell and resembles the fibroblast in many respects. Although the ultrastructural findings indicate an abortive attempt at collagen fibrillogenesis, there is at the same time prominent secretory activity within the tumor cells, resulting in excessive production of acid mucopolysaccharide ground substance. There may also be phagocytosis by tumor cells of residual collagen in the area. Although the ultrastructural findings thus far reported for this tumor are compatible with an odontogenic origin, they arc not incompatible with an origin from primitive nonodontogenic niesmchymnl rests.

T

he odontogenic myxoma is a rclativcly uncommon, but by no means rare, neoplasm that. occurs centrally within the maxilla and mandible. Almost since the first reports of central myxoma of i)one by Bloodgood,‘. L controversy has existed as to its t,rue nature. Historically, the myxoma of the jaws has been regarded by various workers as either odontogenic, osteogenic, both, or neither. Those favoring an odontogenic origin+’ have cited the virtually exclusive occurrence of this tumor in the jaws, its striking histologic resemblance to the dental papilla, and the occasional presence within the tumor of odontogcnic rests. Thoma and Goldman3 theorized that the odontogenic fibroma arises from the mesenchymal portions of the tooth bud and may tliffercntiate into a ccmentoma, a dentinoma, or, in the case of mucoid degeneration, a myxoma. Other workers!‘, Ii) have suggested that the odontogenic myxoma arises from mesenchymal rests located in the alveolar bone. Thoma and (loldman” combined both theories in stating that jaw myxomas could be classified as odontogenic and ostcogcnic, with the former behaving in a benign fashion and the latter acting more aggressively. Several author+ I’ have warned that the “myxoid imitators” may be misdiagnosed as odontogenic myxomas ; others13. I4 have questioned the very exis206

\‘olume 42 Sunnber 2

Fig. 1. Seven-micron sect.ion showing classic features of the odontogenic myxoma: spindly, stellate, and ovoid cells embedded in a myxomatous matrix Cth only scattered collagen fibers. An occasional multinucleated cell is noted. (Hemato~ylin and rosin stain. Magnification, x290.)

tewe of a true mysoma and stated that all myxomatous tumors probably represent myxomatous change in other tumors. The clinical, radiographic, and histologic features of the odontogenic myxoma have been well described in numerous individual case reports as well as in several rcvie\ys,:j. *. 12.IT,-18In adtlition, the histochcmical aspects of this tumor have been studied by sc\cral groups.‘!‘-C’:’ Howcvcr, only four ultrastructural studies of this lesion have been published thus far,l’l =, =I 24 not all of which have reported identical findings. In an effort to add to the knowledge of the nature of this tumor, ant1 sinvc fresh lcsional tissue properly processed for electron microscop> is not commonly available, an ultrastructural study of an additiona. odontogcnic myxoma was undcrta.ken.

METHODS

AND

MATERIALS

A 26-year-oltl ( ‘aucasian woman ljresented nith an odontogenie mysoma (diagnosed by preliminary outpatient biopsy) of the left maxilla. The tumor caused a firm swelling in the left mncobuccal fohl from the region of the cuspid to the tubcrosity. Xatliographs indicatetl obliteration of- the maxillary antrum on that side. The patient \vas taken to the opcmting room, where the tumor was enueleatctl ant1 curctt.ed. The area healed unc~ventfully, and there was no evidence of recurrence 1 year 1)ostoperatively. Representative tissue taken during the operation was immediately placed on a cutting hlovk, immcrsetl in ~ltl 4 per rent glutaraldehyde in Millonig’s phos-

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Fig. 8. Type T cell in longitudinal section showing typical carrot shape, lateral eytoplnsmic~ process II’), prominent HER, cytoplasmic invaginations (I), outpouehings associated with thin collagen fibrils CO), and occasional ground substance-like zones (GSL). Note also patchy amorphous extracellular ground substance supporting scattered collagen fibrils. (Magnification, x10,200.)

phate buffer, and minced into 1 mm. cubes. After fixing overnight in glutaraldehydc, the tissue was post-fixed in 2 per cent osmium tetroxide for 2 hours, washed again in buffer, stabilized in 1 per cent uranyl acetate in water, dehydrated in graded acetones, and embedded in Spurr low-viscosity resin. Sections were cut on a Sorvall Porter-Blum MT-2 ultramicrotome with the use of glass knives. Thick (1 micron) sections were stained with toluidine blue. Thin sections were mounted on stainless steel or copper grids, stained with uranyl acetate and ammonium molybdatc, and examined under an RCA EMU3H electron microscope at 50 kv. RESULTS

Histologic examination of sections stained with hematoxylin and eosin rcvealed the classic microscopic features of the odontogenic myxoma (Fig. 1). Spindly to stellate or occasionally ovoid cells with vesicular nuclei and generally

(M), Golgi Fig. 3. Type I cell in oblique section showing prominc,nt RER, mitochondria (G j, and nucleus with pronlinent nucleolus (NU) and finely granular “fingerprint-like” nuclear body (soTid ~1wot(.). Also note transverse sections of cytoplasnlir infoldings containing collagen filxils (olxn tr~ozr:). (Magnification, x10,200.)

scanty cytoplasm mere sparsely distributed throughout a very mpxomatous stroma exhibiting only a few acattcrcd collagen fibers and abundant amorphous ground suhstanw. Vasvulalsitwas not prominent and no islands of odontogenic epithclium wcrc notctl. Examination with the electron microscope revealed two apparently distinct ccl1 typcls : a secretory ~11 (Type I) and a nonsecretory cell (Type II). A few intcrmctliato foriils wore also noted. Cell Type I, the most common and presumabl; the principal tumor cell, was basically carrot-shaped in three dimensions. In longitudinal section (Fig. ?), root-like extensions of cytoplasm emanated laterall? from the broatlcst quarter of its length, and the qtoplasmic border cxhibitcd occasional invaginations as well as outpouchings, some of the latter being associated with single or mult,iplc short collagen fibrils embcddcd in patches of mildly dcctron-clrnse rstraccllul;tr matrix. Also in longit.uclinal section, the nucleus appcarcd clongatcd and mildly convoluted. In oblique and transverse section (Figs.

Fig. 4. Type I cell in transwrse section showing prominent peripher:dly lwatcd RER (urrow), Golg~ (G), and swollen mitochondria /X) with poorly dt~veloped cristw. (Magnificntion, ~11,600.)

3 and A), this cell type was round to polyhedral, with a highly convoluted nucleus. All sections show4 a cytoplasm that cont.ainctl a large amount of rough endoplasmic reticulum (RER) which was more or less evenly dispersed throughout the cell in some sections (Fig. 3) and confined principally to the periphery in others (Fig. 4). Slitochonclria of the Type I cell were gcnera.lly prominent and were either distributed randomly (Fig. 3) or confined chiefly to the perinuclear region (Fig. 4). They assumed various shapes but most were round to ovoid and rather swollen. The limiting double membranes of these organrllcs were mostly well defined, but the cristae mitochondriales gcncrally were not prominent. A few Type I cells had mitochondria with prominent cristac and an cstremely electron-dense matrix (Fig. 5). The (klgi complex in the Type 1 ccl1 was freyucntly prominent and noted in both peripheral and perinuclear areas (Figs. 3 and 4). Toward the periphery of this type of cell w(‘re a few dilated, smooth-surfacecl, mcmbranc-bound structures

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E’ig. 5. Portion of a Type I cell showing (Magnification, ~38,700.)

Odontogenic

electron-dense

“condensed”

myxomn

mitochondria

2 11

(CM).

containing amorphous, faintly electron-dense material, as well as a few mell-defined, fiber-like structures similar to collagen fibrils in the extracellular vicinit) (Figs. 2 and 3). In some Type I cells, fine cytoplasmic fibrils, 50 to 75 A in diameter, were seen. These were mostly confined to the periphery of the cell and frequently were associated with amorphous electron-dense zones. In some cells, however, thcsc fibrils were present in great abundance and were evenly distributed. Here they ran generally parallel to one another as well as to the long axis of the cell, but coursed around and partially masked the other organelles (Fig. 12). Intracytoplasmic, electron-lucent zones similar to t,hc extracellular ground substance but containing scattcrcd fibrils were frequently seen in the Type I cell (Figs. 2 and 12). The nucleus of the Type I cell was often deeply convoluted, and in some cases may have been multiple (although t.his was not confirmed by serial sections) (Figs. 3 ant1 1). It esl~il~itetl a well-Mined, double-layered nuclear membrane

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F ifJ. 6. ‘gpe 11 rell closely associated with portion of a Type I cell. In Type am and well-defined nucleus and nucleolus. (Magnification, ~14,800. cyt0 F ig. 7. ‘ype II cell showing absence of RER, abundance of fret rihosomcs I I:), and tcrea mitoc ondria (&L). (Magnification, ~14,600.)

note

1hNl

scxt-

punctuated by nuclear pores and had dense, marginated heterochromatin. In many sections there was a very prominent, large, round nucleolus (Fig. 3). In addition, a few small, ovoid, and very finely granular zones, apparently similar to the “fingerprint-like” areas described by White and assoeiates,17 were seen in some sections of the rlucleus (F’igs. 3, 10 and 11). The Type II cell was generally round to ovoid (Figs. 6 and 7). The cytoplasm had an abundant granular matrix which was virtually devoid of RER; however, fret ribosomes were present. A few mitochondria mere noted, but Golgi complex,

\‘olume Sumber

Odoxtogenic

42 2

myxomn

Fig. 8. Collagen fibrils in eytoplasrnic infoldings of a tumor cell. (Magnification, Fig. .9. Chortler of R Type I ccl1 showing fuzziness of plnsmn mctmt~ranc with socktcd tllill collagen fitrils. (Mqylificatiorl, x14,GOO.)

213

~18,500.) rlosrly RS-

if prcwnt, n-as inconspicuous. The nuclcas was round and cxhihitcti prornincnt, chiefly peripherally disposed hettrochromatin. The nuclear envelope remained \vell developctl, and a nucleolus, although not so prominent as that in Cell Type I, was unmistakably present ( Fig. 6). nJ1

3dditiOlMl

filldill~

Of

illtCJ-OSt

W-as

the

presellce

Of

@‘OUpS

Of

Closely

as-

sociated cells of 1)oth Types I and II (Figs. 6 ant1 10). Although there was intiJJlittC? intertwining of their respwtive cellular processes, the plasma membranes of thcsc cells swnrecl to remain illtact (different cells dicl not actually blend their cytoplasm), nor wcrc sopliisticatctl intercellular junctions, such as clcsmosomes, tight ,junctions, etc., erident (Fig. 11) . The intercellular substanw comprised the bulk of the tumor. It consisted of a sea of irrcyular, patchy, finclp granular, and slightly electron-dense material

Fill. 70. Cell grouping. Either a binurleated sociatd with a Type II cell. Note “fingerprint-likt,” xl6,GSO.~

Type I 1~11 or two Type I cells closely asnuclear lmdirs (m7ou~s/. (Magnification,

with no apparent definable structure. Embedded in some of these patches of clectron-dense material were scattered fib&s that occurred either singly or in hunclles of ;lpl)rosimat,clthree to ten. These fibrils had the general structure of collagrn, but ranged from 100 to 100 Ai in diameter (Fig. 2). Two forms of’ closc~ association between cells alltl rollagcn fibrils were noted. One consistetl of ;I blurring or fuzziness of the ~11 bor(lcr, from whic*h emanated individual short collagen fibrils (Fig. 9). The other was the presence occasionally of collagen fibrils in cy?olJlasnric infoldings yicwocl longitntlinall~(Fig. H), as apparently ~~~c~r~~~~r’i~~~~~-l~o~~i~~l structures tlescrihed in well as in the pcril)licral, conjan~~tion with the Type I cell (Fig. 3). DISCUSSION Previous

studies

The first ultrastructural study of the otlontogonk myxoma was that of Harrison.” In \-icw of their \\rll-ckvelopl ( :olgi apparatus and prominent RER, he l~rol~osrd that many of the tumor cells were secretory in nature. Other cells were intcrpretcd as macro~~hages. In addition, he noticed that some cells, which rctainetl only scanty 1213R, containctl bnntllcs of banded collagen fibrils within membralic-l)o~uItl structurrs. Occasionally, thc3c structures communicatetl with the extracellular substance. Most of the extracellular ground substance was amorphous ant1 of low electron density. However, it (lit1 contain a few banded collagen

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Fig. 21. Higher-power micrograph of area in rectangle in Fig. 10. Cell borders intimately intertwined but plasma membranes remain distinct. No ccl1 junctions noted. (Magnification, x35,000.) Fig. 1%. Type I cell showing prominent GSL zones abruptly interrupting longitudinally running intracytoplasmic fibrils (F). (Magnification, x23,100.)

fibrils, as well as scattered electron-dense particles that were less than 700 .P\in diameter, with branching, anastomosing fibrillar processes. Islands of odontogenic cpithelium were also seen, as well as “cavities,” particle-free and fibril-free zones sometimes containing macrophages. Westwood and associak? described the ultrastructure of a giant odontogenic fibromysoma. They found basically one type of connective tissue cell, characterized generally by a lobulated nucleus with finely granular chromatin and a single prominent nucleolus. Some of the cells contained prominent RER, Golgi apparatus, and free ribosomes, and often many fine cytoplasmic filaments about 75 2%in diameter. These filaments, which were most prominent at the periphery, sometimes appeared to be flowing out of the cell through indistinct portions of the plasma membrane. Other cells displayed prominent infoldings of the plasma membrane containing banded collagen fibrils, similar to the findings of Harrison.” Sill other cells contained dilated cisternae of R,ER in which was a light granular ma-

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terial. These cells also showed small, smooth, membrane-bound vesicles in the cytoplasm nea.r the cell membrane. The intercellular substance was described as essentially amorphous gray material supporting fibrils and bundles of banded collagen. Simes and associateP described ultrastructural findings at some variance with those of the previous investigators. The predominant cell observed by these workers exhibited many cytoplasmic fibrils, 100 to 150 ii in diameter, prominent’ Golgi apparatus associated with probable glycogen granules, but almost complete absence of R’ER. These authors also found dense granules 300 to 700 X in diameter with fibrillar projections in the extracellular matrix similar to those described by Harrison.” White and colleagues I7 described two principal types of cells in their ultrastructural study of an odontogenic myxoma. The “pale” cell was quite similar to the principal tumor cell described by Harrison” and by Westwood and coworkersZ2 but, in addition, it had “fingerprint-like” nuclear bodies and a moderately dense population of intracytoplasmic filaments 60 to 80 B in diameter. The “dark” cell contained many invaginations of the plasma membrane, very densely packed cytoplasmic filaments, and prominent “fingerprint-like” nuclear bodies. These authors also described the presence of intracisternal banded collagen fibrils and an extracellular matrix which was essentially electron-lucent, with small patches of fine granular material and occasional collagen fibrils 450 A in diameter. Present

study

The ultrastructural findings in the present study demonstrate the presence of two basic functional types of cells: secretory and nonsecretory. The Type I cell appears to be a fibroblast-like secretory type of cell. The prominent Golgi and RER are widely recognized as being the ultrastructural indicators of synthesis of protein destined for transport out of the ~rll.~~ The presence of swollen mitochondria and indistinct zones of plasma membrane with intimately associated thin collagen fibrils has been associated wit,h fibroblasts engaged in collagen deposition2” The presence of intracellular filaments approximately 50 -?, in diameter coursing longitudinally through the cytoplasm and presenting most prominently at the periphery has also been observed in fibroblasts engaged in fibrillogenesis.27-2Q The presence of numerous ground-substance-like (GSL) zones in some Type I cells would seem to indicate zones of cell breakdown or possibly externally induced damage. Although the possibility that the appearance of GSL zones could have resulted from a tangential tissue cut was considered, this is unlikely in view of the irregular margins of the GSL zones, with no indication of cell membrane boundary. The significance of the “fingerprint-like” nuclear bodies originally described by White and colleagucsl’ and also found in Type J cells in the present study is unknown. Wesley and co-workers 3o found similar structures in the nuclei of an odontogenic fibroma and interpreted them as the Type I variety of nuclear body described by Bouteille and associates, 31 indicative of general cellular hyper-

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activity. It is also conceivable that these very finely granular masses within the nucleus might represent either accessory nucleoli or lobes of a multilobulated nucleolus. The Type II cell appears to represent a nonsecretory, but not necessarily completely quiescent, cell. The lack of Golgi and the sparse RER would indicate that it is not engaged in significant secretory activity. However, the prominent nucleus, nucleolus, and free ribosomes indicate that protein synthesis is still occurring. lntracytoplasmic

fibrils

One of the most intriguing features of the Type I cell in the present study is the presence of intracytoplasmic longitudinal fibrils 50 to 75 B in diameter. Intracytoplasmic fibrils 30 to 150 A in diameter have been reported in many types of normal and neoplastic cells,“” and those in the 40 to 80 A range have been interpreted as representing strands of F-actin.“” (Nevertheless, differences in the state of protein aggregation as well as different preparative techniques may affect the apparent width of such fibrils.33) Similar intracytoplasmic fibrils have also been observed in the contractile fibroblasts of granulation tissuea and hypcrtrophic scars,3+37 also implying a contractile role for them. Fibroblasts of the dental pulpz8 and dental papilla3” also exhibit such fibrils. Interestingly, 100 d intracytoplasmic fibrils, which may serve a cytoskeletal function,3z have been observed in the mesenchymal cells of the umbilical cord.40* 41 These fibrils have been shown to appear much more prominent when the cord is fixed in a distended state than when collapsed.41 This observation would seem to imply a role for local environmental forces in the expression of intracytoplasmic fibrils. The finding of intracytoplasmic fibrils in three of the five (including the present) studies of the odontogcnic myxoma suggests that their role may be a significant one. Whether they serve a contractile, cytoskeletal, or other function remains to be determined; but, clearly, these possibilities exist. Intracellular

collagen

fibrils

The finding of apparently intracellular collagen fibrils (ICF) in several of bhe ultrastructural studies of the odontogenic myxoma may be of considerable significance. Harrison” thought that this finding indicated collagen phagocytosis by tumor cells; Wcstwood and associates22 intcrpretcd it as an illusion due to plane of section ; and White and associates’7 thought that it was due to premature intracisternal crystallization of the collagen. Other investigators have studied the phenomenon of ICF in fibroblasts of regenerating tissues,*“, 42,43 granulation tissue,‘” and neoplasms and reactive processes,4’,45and have also reached varying conclusions in regard to the significance of ICF. In the present study, no ICF could be found. However, a few cells with cytoplasmic infoldings that contained collagen fibrils were demonstrated. In addition, a few vacuolar structures that contained cross sections of collagen fibrils were observed near the periphery of some tumor cells. These structures wverc interpreted as being cytoplasmic invaginations that contained extracellular col-

lagen fibrils cut in transverse section. It’ the collagen fibrils that others describe in the odontogenic mgxoma actually lie within tubular structures of the cell (rather than in caytoplasmic infoldings), it, is probably the result, of dlagen resorption by the tumor cell. Mitochondria

In the present study, mitochondria with extremely electron-dense matrix and prominent cristac were seen in a few cells. This finding has not been reported preyiousl>- in the odontogenic myxoma but has hecn described as the condensed form of mitochontlris in isolates of liver mitochondria.-l”, -‘; This finding has been shown to parallel reversible suppression of oxidative phosphorylation and thus ma?- be indicative of cells in a depressed state of metabolic activity. It also lends support to the histochemical findings of Harrison” and Mori and co-worker? which indicated a low respiratory enzyme activity within the tumor cells, compatible with the relatively slow growth of this tumor. Intercellular

matrix

The intercellular matrix of the odontogcnic myxoma has been shown by several histochemical studies to bc composed of acid mucopolysaccharides, principally hpaluronic acid and chondroitin sulfate,“‘-‘” and excessive production of acid mucopolysaccharides is the distinguishing characteristic of the “myxoblast.“20 Similar findings have been observed in the tooth bud.“’ Harrison” an<1 Simes and associates” confirmed the presence at the ultrastructural lcvcl of acitl mucopolysaccharitlcs in t.hc form of scattered intercellular granules 400 to 700 A in tliamcter in association with thin, anastomosing fibrils.‘$ Such granulrs were not reported in the studies of Westwood and associates,” White and associafes,” or the present study. The variability of this finding may 1);~ different bc caused 1)~ different preparative techniques, and particularly staining procedures. In any case, cxisbing histochemical studies seem to firmly matrix of establish t.hc ncitl-mucopolvsaccharitlc natnrt~ of’ the cstraccllular the odontogeiiic myxoma. Cell

groupings

The significance of the occasional observation of groups of closely associated cells is unknown. The association may be a transient one, as reflectctl by the lack of sophisticated intercellular junctional complexes. On the other hand, the association ma?- bc indica,tive of imminent phagocytosis of one cell by another. SUMMARY

AND

CONCLUSIONS

This study has confirmed the basic similarity between the principal tumor cell of the otlontopc~nic myxoma and the classic fil)roblast. HowetTer, t.hc myxoma cell is certainl)- not a typical fibroblast. The ultrastructural findings seem to indicate an attempt, at collagen fibrillogenesis, with little ultimate success. At the same time there is prominent secretory activity within the tumor cells, presumably resulting in the cxcessivu production OSacid-mucopolysaccharide matrix 111addition, ac*c*ording to other investigators, there may be actual phagocytosis

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219

I)?- tumor cells of the little collagen that remains in the area. Perhaps the term myxoblnst is, after all, appropriate for this tumor cell. Furthermore, the myxoma cell shows many characteristics in common with the fibroblasts of the dental papilla,“!’ the dental pulp,“” and the oclontogcnic fibroma,“” a finding which is certainly compatible with an oclontogenic origin fog this tumor. On the other hand, odontogcnic origin cannot be proved solely 1)~ the ultrastructural evidence that has so far been ad\-an&l, inasmuch as the mFsoma cell also bears considerable resemblance to the cells of the umbilical cord.*“~ I1 Thus origin from primitive nonodontogenic mesenchymal rests cannot be complctcly ruled out by the existing ultrastructural studies. I gratefully acknowledge the help of Mrs. Mary Ann Lupear in the preparation of the tissue sections; Mr. Richard Scott, Mr. Michael Halloran, and Mrs. Alana Fears for assistance with the illustrat,ions; and Mrs. Jane Powell for typing the manuscript.

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Surg. 33: 532-540, 1947. 1). C., and Dahlin, D. C.: Myxomntous Tumors of t,he Jaws, 01~1, SVKG. 11: 1069-1080, 1958. Shafer! W. G., Hine, M. Ii., and Levy, B. M.: A Textbook of Oral Pathology, ed. 3, Philadelphla, 1974, W. B. Saunders Company, pp. 26’5-266. Gorlin, R. J., and Goldman, H. M.: Thoma’s Oral Pathology, cd. 6, St. Louis, 1970, The C. V. Mosby Company, pp. 501-503. Jaffr, IT. L.: Tumors and Tumorous Conditions of the Bones and Joints, Philadelphia, 1968, Lea & Febiger, pp. 435-436. Dahlin, D. C.: Bone Tumors, ed. 2, Springfield, Ill., 1970, Charles C Thomas, Publisher, p.

4. Zimmerman, 5. 6. i. 8.

278. 9. Harbert, 10 Il. 12.

13. 14.

F., Gerry, R. G., and Dimmcttc, 1~. RI.: Myxomn of the Maxilla, ORAL Suw. 2: 1414-1421, 1949. Bruce, K. TV., and Royer, R. Q.: Central Fibromysoma of the Maxilla, ORAL SURG. 5: 1277.1281, 19521. Thoma, k. H., and Goldman, H. M.: Oral Pathology, ed. 5, St. Louis, 1960, The C. IT. Mosby Company, p. 1193. Stout, A. I’.: Myxoma, the Tumor of Primitive Mcsenchyme, Ann. Surg. 127: 706-719, 1948. Willis, R. A.: Pathology of Turnours, ed. 4, London, 1967, Butterworth, p. 66s. Lichenstein, I,.: Bone Tumors, cd. 4, St. Louis, 1972, The C. V. Mosby Company, pp. 1O-l 1,

66-67. 15. Barros, R. E., Dominguez, F. V., and Cabrini, R. I,.: Myxoma of the Jaws, 27: 225-236, 1969. 16. Ghosh, B. C., Huvos, A. G., Gerold, F. P., and Miller. T. R.: Mvxoma of the Cancer 31: 237-240, 1973. 17. IVhite, D. K., Chen, S.-Y., Mohnae, A. M., and Miller, A. S.: Odontogenic Clinical and Ultrastructural Study, ORAI, SURG. 39: 901-917, 1975. 78. Kangur, T. T., Dahlin, D. C., and Turlington, E. G.: Mysomntous Tumors of 19. 20. 21. 22.

23

ORAL SUKG. Jaw Bows, Mysoma.

A

the Jaw-s, J. Oral Burg. 33: 523-528, 1975. Sedano, H. O., and Gorlin, R. J. : Odontogenic Myxoma: Some Histochemical Considerations. Arch. Oral. Biol. 10: 727-729. 1965. Pro&, R. E. R., and Hodson, J. J:: Analysis of the Mucopolysaccharide of a Myxoma of the Mandible, Nature 218: 99-100, 1968. Harrison, J. D. : Odontogenic Myxoma: Ultrastructural and Histochemicnl Studies, J. Clin. Pathol. 26: 570-582, 1973. Wcstmood, R. M., Alexander, R. IV., and Bennett, D. E.: Giant Odontogenic Myxofibroma. Report of a Case With Histochemical and Ultrastructural Studies and a R&iew of the Literature. ORAJ, SIJRG. 37: X3-92. 1974. Mori, M., ‘Murakami, M., Hirose,’ I., and Shimozato, T.: Histochemical Studiw of Myxomx of the Jaws, J. Oral Surg. 33: 529-536, 1975.

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