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Fibrous dysplasia in the upper jaw undergoing myxomatous degeneration
USIITON’ describes fibrous dysplasia as a condition “characterized by eha-nges in one or many bones which consist in resorption of the spongy bone and to some extent of the cortex, and replacement by fibrous tissue of the bone and marrow. In this fibrous tissue osteoid and bone and occasionally cartilage can develop ; or the fibrous tissue m.ay undergo mucinoid (myxomat,ons) degeneration. ” The present report deals with a case of the monostotic type of fibrous dysplasia observed in the upper jaw a,ntl shows all the tissue changes described above.. Report of a Case A
17-year-old Filipino boy was admitted to a hospital with a complaint of a nonpainful mass in the right side of the maxilla. The mass was about 3 inches in its longest diameter and of a,bout three years’ duration. It started as a small nodule the size of a kernal of corn, bony in consistency, nonmovable, and nonpainful. Two years after it WaS noticed, however, the patient experienced slight to moderate headache, usually localized at the right temporal region, The patient had no history of recurrent maxillary sinusitis. The mass was surgically removed and histologic sections were made of the specimen. Histologic Findings.-Fig. 1 is a photomicrograph of a section from the molar region of the maxilla showing one marrow space already filled with a highly cellular fibrous tissue The trabecular bone appears to be and another space still containing a yellow marrow. lamellar or matured bone. Fig. 2 is a photomicrograph of another section, showing in higher magnification the fibrous tissue undergoing myxomatous degeneration. The connective tissue cells arc now differentiating into stellate cells, with long processes chasacteristic of the cells’ in the so-called myxoma. The spongy or trabecular bone in this section appears to be of the immature type, or nonlamellar, and seems to be undergoing rapid formation, as indicated by the presence of a relatively wide osteoid tissue. Fig. 3 shows the Gbrous tissue in one area in a state of advanced myxomstous degeneration. In other areas, the fibrous tissue appears to be not yet affected, but causing resorption of the matured bone and replaeement of the same by immatured bone. We were unable to observe the presence of osteoclasts resorbing the bone in all our sections. In Fig. 4, B a In Fig. section in silver staining shows cartilaginous tissue at the fundus of the tooth socket. 4-, B a higher magnification of a certain portion of the cartilaginous mass shows a remnant of the old bone, which has escaped complete resorption, embedded in the cartilage. IIt From the Department of the Philippines.
of
Oral
ETistology
and 400
Pathology,
College
of Dentistry,
University
FIBROUS
Fig. tissue; Fig. transformed myxoma. Fig. tissue in of matured
DYSPLASIA
IN
UPPER
JAW
Fig.
1.
Fig.
2.
Fig.
3.
I.---Section from molar region of maxilla. A, Area filled with highly cellular fibrous B, area with yellow marrow; mb, matur'ed bone. 2.-Fibrous tissue undergoing myxomatous degeneratiOr1. Note connective tissue cells into stellate cells with long processes characteristic of the cells of the so-called iv&, Immatured bone; ost, osteoid tissue. Alled with highly cellular fibrous tissue; R, fibrous 3.-Another section: A, area imb, newly formed immature bone; mb, remnant state of myxomatous degeneration; bone undergoing resorption.
Fig. separated remnant B, probably
Pig.
4.-A, Section at fundus of tooth socket. d, Dentine: art, artifact. from cementurn, c, during histologic preparation : gclwb, periodontal Silver staining. of resorbed matured bone; CT, cartilage tissue. IT&her magnification. Note cartilage cells. hs, Remnant of the a single 1-Ta.versia.n system.
5”--Section
isla.nd
of
showing fibrous
fibrous tissue tissue not yet
degenerated completely
into transformed
typical
into
myxomatous myxomatous
Dentine membrane
was ; hs,
matured
bone,
tissue. tissue.
a,
An
FIDROUS
DYSPLASIA
IN
TJPPER
403
JAW
appears that the resorbed old bone in this portion of the jaw has been replaced by cartilaginous tissue. In our observation, it seems that some cells of the periodontal membrane developed into cartilage cells, or chondroeytes. Fig. 5 shows an area of a typical myxomatom tissue. It may be noticed that an island of fibrous tissue which has not yet degenerated into a myxomatous tissue is still present in the center of the illustration. Fig. 6, A is a photomierograph o-f another section showing the periodontal membrane already involved in myxomatous degeneration. Fig. 6, B, the same section in low magnification, shows the extent of the myxomatous degeneration near the anterior portion of the maxilla. Remnants of the trabecular bone and the cortical bone in the palatal side are still present. From the foregoing observations, i.t appears that the lesion started near the anterior region of the maxilla and gradually extended to the posterior region. As shown, the anterior region is more extensively involved in myxomatous degeneration than the posterior region.
A.
B
6.-A, Section from incisor region of maxilla showing periodontal membrane already in myxomatous degeneration. d, Dentine ; pdnz, ueriodontal membrane; n%t, myxtissue; b, bone; 9. gingival tissue. B,, Lower magnification showing extent of myxomatous degeneration in anterior por$o;t of maxilla. g, Gingival tissue : cb, cortical bone of the palate; nzt, myxomatous tissue. extensive resorption of the trabecular or spongy bone. Fig.
involved omatous
The changes that took place in the present ca.seappear to consist, first, of of the bone marrow by highly cellular fibrous tissue. Second, of the matured or lamellar bane the fibrous tissue seems to cause resorption and. the replacement of the same by immatured or noulamellar bone. It could whether the replacement follows the same a,rehitectural not be ascertained of the old bone. Third, for some unknown cause, the fibrous tissue pattern undergoes mucinoid or myxom.atous degeneration. Fourth, the myxomatous of the immatured bone and remnants of the tissue appears to cause resorption matured bone which have escaped resorption before. Fifth, to protect itself from the advancing myxomatous degeneration, the periodontal membrane the replacement
forms cartilaginous tissue. This mode of protection, however, seems to be a, slow process or not so effective, as in some areas the periodontal membrane is It appears that the cartilage already involved in myxomatous degeneration. is more resistant Ihau the hone to the effwt, of myxnmatons t.issue.
Fibrous dysplasia is regarded by some investigators as a developmenta,l hyperpfasia, the etiology of which is not yet definitely known. At present, it seems that there is need for clarification as to whether fibrous dysplasia occurring in the jaw and certain jaw lesions currently described as “ossifying fibroma’ ’ and ” fibro-osteoma” are different pathologic entities or simply variants of the same condition Some cases of ossifying fibroma a.s described by Weinma.nn and Siche? could hardly be distinguished histologically from fibrous dysplasia as reported by Schlumberger.3 Other cases of ossifying fibroma appear histologically similar to fibro-osteoma as described by Thoma.4 Anderson” classified ossi-fying fibroma and fibro-osteoma occurring in the jaws under the general. heading, fibrous dysplasia. Willis6 states that there is no such cell as a “myxoblast” distinct from a fibroblast. “Myxomas and myxosarcomas are then merely fibromas and fibrosarcomas in which mucin has developed in the intercellular matrix.” In the classification of neoplasm in the mouth, however, the so-called central and peripheral myxomas are included.’ IJnder this classification, the case reported here can be regarded as a. central myxoma in the upper jaw. Th.e findings, however, seem to suggest quite strongly that this is a case of mucinoid or myxomatous degeneration of fibrous tissue and not a true or primary rnyxoma. It seems possible that some so-called myxomas found in the jaws are not really true neophsmx. The author acknowledges the courtesy fessorial T,ecturer of Oral Surgery, College who made available the specimen used in this
extended to him by Dr. of Dentistry, University report.
Jaime E. Laico, Proof the Philippines,
References 3. Rushton, 2. 3. 4. 5. 6. 7.
M. A.: Fibrous Dysplasia of Bone: Arrested Jaw Lesions, Brit. D. J. 89: 185. 1950. Weinmann, J. P., and Sicher, H.: Bone and Bones, St. Louis, 1947, The C. V. Mosby Company, pp. 367374. Schlumberger, H. G.: Fibrous Dysplasia (Ossifying Fibroma) of the Maxilla and Mandible, Am. J. Orthodontics and Oral Surg. 32: 579, 1946. Thoma, I(. H.: Oral Pathology, St. Louis, 1944, The C. V. Mosby Company, pp. 988-993. Anderson, W. A. I).: Pathology, St. Louis, 1948, The C. V. Mosby Company, p. 1303. Willis, R. A.: Pathology of Turnours, London, 1948, Butter-worth & Co.,, p. 653. Stones, H. H.: Oral and Dental Diseases, Rnltlmore, 1948, Williams & Wilkins Company, pp. 776, 791-793.
17-year-old Filipino boy was admitted to a hospital with a complaint of a nonpainful mass in the right side of the maxilla. The mass was about 3 inches in its longest diameter and of a,bout three years’ duration. It started as a small nodule the size of a kernal of corn, bony in consistency, nonmovable, and nonpainful. Two years after it WaS noticed, however, the patient experienced slight to moderate headache, usually localized at the right temporal region, The patient had no history of recurrent maxillary sinusitis. The mass was surgically removed and histologic sections were made of the specimen. Histologic Findings.-Fig. 1 is a photomicrograph of a section from the molar region of the maxilla showing one marrow space already filled with a highly cellular fibrous tissue The trabecular bone appears to be and another space still containing a yellow marrow. lamellar or matured bone. Fig. 2 is a photomicrograph of another section, showing in higher magnification the fibrous tissue undergoing myxomatous degeneration. The connective tissue cells arc now differentiating into stellate cells, with long processes chasacteristic of the cells’ in the so-called myxoma. The spongy or trabecular bone in this section appears to be of the immature type, or nonlamellar, and seems to be undergoing rapid formation, as indicated by the presence of a relatively wide osteoid tissue. Fig. 3 shows the Gbrous tissue in one area in a state of advanced myxomstous degeneration. In other areas, the fibrous tissue appears to be not yet affected, but causing resorption of the matured bone and replaeement of the same by immatured bone. We were unable to observe the presence of osteoclasts resorbing the bone in all our sections. In Fig. 4, B a In Fig. section in silver staining shows cartilaginous tissue at the fundus of the tooth socket. 4-, B a higher magnification of a certain portion of the cartilaginous mass shows a remnant of the old bone, which has escaped complete resorption, embedded in the cartilage. IIt From the Department of the Philippines.
of
Oral
ETistology
and 400
Pathology,
College
of Dentistry,
University
FIBROUS
Fig. tissue; Fig. transformed myxoma. Fig. tissue in of matured
DYSPLASIA
IN
UPPER
JAW
Fig.
1.
Fig.
2.
Fig.
3.
I.---Section from molar region of maxilla. A, Area filled with highly cellular fibrous B, area with yellow marrow; mb, matur'ed bone. 2.-Fibrous tissue undergoing myxomatous degeneratiOr1. Note connective tissue cells into stellate cells with long processes characteristic of the cells of the so-called iv&, Immatured bone; ost, osteoid tissue. Alled with highly cellular fibrous tissue; R, fibrous 3.-Another section: A, area imb, newly formed immature bone; mb, remnant state of myxomatous degeneration; bone undergoing resorption.
Fig. separated remnant B, probably
Pig.
4.-A, Section at fundus of tooth socket. d, Dentine: art, artifact. from cementurn, c, during histologic preparation : gclwb, periodontal Silver staining. of resorbed matured bone; CT, cartilage tissue. IT&her magnification. Note cartilage cells. hs, Remnant of the a single 1-Ta.versia.n system.
5”--Section
isla.nd
of
showing fibrous
fibrous tissue tissue not yet
degenerated completely
into transformed
typical
into
myxomatous myxomatous
Dentine membrane
was ; hs,
matured
bone,
tissue. tissue.
a,
An
FIDROUS
DYSPLASIA
IN
TJPPER
403
JAW
appears that the resorbed old bone in this portion of the jaw has been replaced by cartilaginous tissue. In our observation, it seems that some cells of the periodontal membrane developed into cartilage cells, or chondroeytes. Fig. 5 shows an area of a typical myxomatom tissue. It may be noticed that an island of fibrous tissue which has not yet degenerated into a myxomatous tissue is still present in the center of the illustration. Fig. 6, A is a photomierograph o-f another section showing the periodontal membrane already involved in myxomatous degeneration. Fig. 6, B, the same section in low magnification, shows the extent of the myxomatous degeneration near the anterior portion of the maxilla. Remnants of the trabecular bone and the cortical bone in the palatal side are still present. From the foregoing observations, i.t appears that the lesion started near the anterior region of the maxilla and gradually extended to the posterior region. As shown, the anterior region is more extensively involved in myxomatous degeneration than the posterior region.
A.
B
6.-A, Section from incisor region of maxilla showing periodontal membrane already in myxomatous degeneration. d, Dentine ; pdnz, ueriodontal membrane; n%t, myxtissue; b, bone; 9. gingival tissue. B,, Lower magnification showing extent of myxomatous degeneration in anterior por$o;t of maxilla. g, Gingival tissue : cb, cortical bone of the palate; nzt, myxomatous tissue. extensive resorption of the trabecular or spongy bone. Fig.
involved omatous
The changes that took place in the present ca.seappear to consist, first, of of the bone marrow by highly cellular fibrous tissue. Second, of the matured or lamellar bane the fibrous tissue seems to cause resorption and. the replacement of the same by immatured or noulamellar bone. It could whether the replacement follows the same a,rehitectural not be ascertained of the old bone. Third, for some unknown cause, the fibrous tissue pattern undergoes mucinoid or myxom.atous degeneration. Fourth, the myxomatous of the immatured bone and remnants of the tissue appears to cause resorption matured bone which have escaped resorption before. Fifth, to protect itself from the advancing myxomatous degeneration, the periodontal membrane the replacement
forms cartilaginous tissue. This mode of protection, however, seems to be a, slow process or not so effective, as in some areas the periodontal membrane is It appears that the cartilage already involved in myxomatous degeneration. is more resistant Ihau the hone to the effwt, of myxnmatons t.issue.
Fibrous dysplasia is regarded by some investigators as a developmenta,l hyperpfasia, the etiology of which is not yet definitely known. At present, it seems that there is need for clarification as to whether fibrous dysplasia occurring in the jaw and certain jaw lesions currently described as “ossifying fibroma’ ’ and ” fibro-osteoma” are different pathologic entities or simply variants of the same condition Some cases of ossifying fibroma a.s described by Weinma.nn and Siche? could hardly be distinguished histologically from fibrous dysplasia as reported by Schlumberger.3 Other cases of ossifying fibroma appear histologically similar to fibro-osteoma as described by Thoma.4 Anderson” classified ossi-fying fibroma and fibro-osteoma occurring in the jaws under the general. heading, fibrous dysplasia. Willis6 states that there is no such cell as a “myxoblast” distinct from a fibroblast. “Myxomas and myxosarcomas are then merely fibromas and fibrosarcomas in which mucin has developed in the intercellular matrix.” In the classification of neoplasm in the mouth, however, the so-called central and peripheral myxomas are included.’ IJnder this classification, the case reported here can be regarded as a. central myxoma in the upper jaw. Th.e findings, however, seem to suggest quite strongly that this is a case of mucinoid or myxomatous degeneration of fibrous tissue and not a true or primary rnyxoma. It seems possible that some so-called myxomas found in the jaws are not really true neophsmx. The author acknowledges the courtesy fessorial T,ecturer of Oral Surgery, College who made available the specimen used in this
extended to him by Dr. of Dentistry, University report.
Jaime E. Laico, Proof the Philippines,
References 3. Rushton, 2. 3. 4. 5. 6. 7.
M. A.: Fibrous Dysplasia of Bone: Arrested Jaw Lesions, Brit. D. J. 89: 185. 1950. Weinmann, J. P., and Sicher, H.: Bone and Bones, St. Louis, 1947, The C. V. Mosby Company, pp. 367374. Schlumberger, H. G.: Fibrous Dysplasia (Ossifying Fibroma) of the Maxilla and Mandible, Am. J. Orthodontics and Oral Surg. 32: 579, 1946. Thoma, I(. H.: Oral Pathology, St. Louis, 1944, The C. V. Mosby Company, pp. 988-993. Anderson, W. A. I).: Pathology, St. Louis, 1948, The C. V. Mosby Company, p. 1303. Willis, R. A.: Pathology of Turnours, London, 1948, Butter-worth & Co.,, p. 653. Stones, H. H.: Oral and Dental Diseases, Rnltlmore, 1948, Williams & Wilkins Company, pp. 776, 791-793.