FUJIMURA
1015
AND ENOMOTO
rate of growth, and speed of recurrence. When definitive excisional surgery is indicated, the ability to provide functional and esthetic reconstruction is essential. Radiotherapy has not been shown to be effective in treating giant cell jaw lesions.8~‘7 It is inappropriate therapy for benign lesions, especially in children, because of long-term interference with growth and the potential for development of malignancy.4 References
8. 9. IO. 11. 12.
13. 14.
I. Dehner LP: Tumors of the mandible and maxilla in children. I. Clinicopathologic study of 46 histologically benign lesions. Cancer 31:364. 1973 2. Chuong R, Kaban LB: Diagnosis and treatment of jaw tumors in children. J Oral Maxillofac Surg 43:323, 1985 3. Jaffe HL: Giant-cell reparative granuloma, traumatic bone cyst, and fibrous (fibro-osseous) dysplasia of jawbones. Oral Surg 6:159, 1953 4. Austin LT, Dahlin DC, Royer RQ: Giant-cell reparative granuloma and related conditions affecting the jaw bones. Oral Surg Oral Med Oral Path01 12:1285, 1959 5. Waldron CA, Shafer WG: The central giant cell reparative granuloma of the jaws. An analysis of 38 cases. Am J Clin Path01 45:437, 1966 6. Chuong R, Kaban LB, Kozakewich H, et al: Central giant cell lesions of the jaws: A clinicopathologic study. J Oral Maxillofac Surg 44:708, 1986 7. Auclair PL, Cuenin P, Kratochvil FJ, et al: A clinical and histomorphologic comparison of the central giant cell granuloma
J Oral Maxillofac
15. 16.
17. 18. 19.
20.
21.
and the giant cell tumor. Oral Surg Oral Med Oral Path01 66: 197, 1988 Bondi R, Urso C, Santucci B, et al: Giant cell lesion of the jaw. Case report. Tumori 74:479, 1988 Shklar G, Meyer I: Giant-cell tumors of the mandible and maxilla. Oral Sum Oral Med Oral Path01 14:809. 196 1 Small GS, Rowe NH: A “true giant cell tumor” in the mandible? J Oral Surg 33:296, 1975 _ Leban SG. Leoow H. Stratiaos GT. et al: The aiant cell lesion of jaws:‘Neoplastic or reparative’ J Oral Su< 29:398, 197 1 Lucas RB: Giant cell lesions, in Lucas RB (ed): Pathology of Tumors of the Oral Tissues, (ed. 4) Edinburgh, Scotland, Churchill Livingstone, 1983, p 262 Homer K: Central giant cell granuloma of the jaws: A clinicoradiological study. Clin Radio1 40~622, 1989 Som PM, Lawson W. Cohen BA: Giant-cell lesions of the facial bones. Radiology 147:129, I983 Rhea JT, Weber AL: Giant-cell granuloma of the sinuses. Radiology 147:135, 1983 Smith PG, Marrogi AJ, Delfino JJ: Multifocal central giant cell lesions of the maxillofacial skeleton: A case report. J Oral Maxillofac Surg 48:300, 1990 Smith GA, Ward PH: Giant-cell lesions of the facial skeleton. Arch Otolaryngol 104:186, 1978 Quick CA, Anderson R, Stool S: Giant cell tumors ofthe maxilla in children. Laryngoscope 90:784, 1980 Hutter RVP. Worcester JN, Francis KC, et al: Benign and malignant giant cell tumors of bone. A clinicopathological analysis of the natural history of the disease. Cancer 15:653, 1962 Mintz GA, Abrams AM, Carlsen GD, et al: Primary malignant giant cell tumor of the mandible. Report of a case and review of the literature. Oral Surg 5 1:164. 198 1 Andersen L, Fejerskov 0, Philipsen HP: Oral giant cell granulomas. A clinical and histological study of-129 new-cases. Acta Path01 Microbial Stand 8 1:606, 1973
Surg
50:1015-1017,1992
Lipoma of the Tongue With Cartilaginous Change: A Case Report and Review of the Literature N. FUJIMURA,
DDS, PHD,* AND S. ENOMOTO,
Although lipoma can occur in any part of the body, it is infrequently found in the oral cavity.lm3It is a benign lesion composed of mature fat tissue that is arranged in lobules that are separated by septa of fibrous
Received from the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, Tokyo. * Formerly, Instructor; currently, in private practice. 7 Chief and Professor. Address correspondence and reprint requests to Dr Fujimura: Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, 5-45, Yushima, 1-Chome, Bunkyo-ku, Tokyo 113, Japan. 0 1992 American
Association
0278-2391/92/5009-0017$3.00/O
of Oral and Maxillofacial
Surgeons
DDS, PHDt
tissue and surrounded by a thin fibrous capsule. Some variants of lipoma have been classified histologically according to the kind and the amount of the tissue other than fat that is present.294 The most common is fibrolipoma, which contains an increased amount of fibrous connective tissue between the fat cells. Others include angiolipoma with an excess of capillaries, and myxolipoma with wide areas of myxoid change. Lipoma with osseous or cartilaginous change is the rarest variant. Overall, there are 13 cases of this variant that were reviewed by Allen’ and 4 cases presented by Katzer.6 In the oral cavity, only five such lipomas have been reported.‘-” Thus, this case is the sixth intraoral lipoma with osseous or cartilaginous change to be described in the literature.
1016
LIPOMA
OF THE TONGUE
WITH
CARTILAGINOUS
CHANGE
Discussion
FIGURE
1. Mass attached to inferior surface of the tongue.
Report of Case A S-year-old man was seen on July 8, 1983 with a painless mass on the inferior surface of the tongue that the patient had first noted about 2 months previously. The lesion was oval, well-circumscribed, and measured 15 mm X 10 mm. A yellowish tinge was visible through the normal overlying mucosa (Fig 1). On palpation, it was tender and contained a hard central area. The mass was not related to the mandible. Under local anesthesia, the mass was excised, including the overlying mucosa, and the wound was closed primarily. The postoperative course was uneventful. Histologically, the tumor consisted of mature adipose tissue that was thinly encapsulated and two foci of mature cartilage, which were located within the fa%y tissue. The cartilage was surrounded by fibrous tissue that had partly undergone myxoid change. The larger nodule of cartilage had a very irregular outline and a garlandlike shape, as described by Katzer.6 No evidence of neoplastic change was found in the sections examined (Fig 2). The patient was last examined on April 25, 1990 and no recurrence was found.
Osseousor cartilaginous change, which occurs in some types of soft tissue tumors, has rarely been found in lipoma. In the oral and head and neck region, only six such lipomas have been reported. One of these tumors occurred in the submandibular region,’ ’ and the other five occurred in the oral cavity.‘-” The features of intraoral lipomas with osseous or cartilaginous change are summarized from a review of the previous five cases and our case (Table 1). We have investigated whether the reported tumors were related to bone. In the case of the tumor in the sublingual region,’ the lipoma was most likely attached to the periosteum of the genial tubercles of the mandible, because the investigators stated that dissection of the tumor from the periosteum was extremely difficult. Two other tumors located in the mandibular buccal vestibule*,” were adjacent to the mandibular bone or periosteum, although they seemed clinically intact and separate from it, as mentioned by the investigators. The remaining three cases were two tumors of the lower lip9,10and one of the tongue (as described in this report). All contained cartilage and were unrelated to bone. It has been stated that lipomas with osseous or cartilaginous change lying adjacent to bone should be called parosteal or periosteal lipomas to distinguish from those unrelated to bone. It is also suggested that they most likely comprise two separate clinicopathologic entities with a different pathogenesis,12 and that the possibility of osseous or cartilaginous change increases in lipomas located close to bone, periosteum, or joint capsules.6 Some pathologists regard such variant lipomas as benign mesenchymomas, because both adipose and chondroid or osseous components origi-
FIGURE 2. Lipoma with cartilage formation. A, Some foci of mature cartilage with an irregular outline are seen within the fatty tissue (hematoxylin-eosin stain, original magnification X 13). B, Cartilage with spaces occupied by fibrous tissue showing myxoid change (hematoxylineosin stain, original magnification X67).
1017
FUJlMURA
AND ENOMOTO
Table 1.
Intraoral Lipomas With Osseous and Cartilaginous Change Age (Yd
Sex
Godbyet al.’
54
M
Sublingualregion
Hughes’
69
M
Buccal mandibular sulcus
McAndrew et al9
12
M
Lower lip
2.5 x 1.5
Allard et al”
81
F
3.5 x 2
Allard et al” Fujimura & Enomoto
69 56
F M
Buccal mandibular sulcus Lower lip Tongue
1x1 1.5 x 1
Reference
Location
Size (cm)
Duration
7X6X3
1v
3.5 X 2.6 x 1.7
Metaplasia
Relation to Bone
Osseous Osseous
+ 2
6 mo
Cartilaginous
_
30-40 yr
osseous
2
2 yr 2 mo
Cartilaginous Cartilaginous
-
-
1.2X 0.5 x 0.6
nate from mesenchymal tissues.4 However, this term should probably not be applied to those variant lipomas in which adipose tissue predominateq6 or the term could cause confusion. l2 This variant lipoma can be distinguished from an osteocartilaginous choristoma, which commonly occurs in the tongue, because it usually contains less fatty tissue. In addition, the differential diagnosis includes metastatic chondrosarcoma or osteosarcoma, liposarcoma with metaplasia, and posttraumatic chondrification.6 Although the exact origin of the fat cells, chondroblasts, and osteoblasts remains controversial, it is generally accepted that they develop from different types of undifferentiated mesenchymal cells. Therefore, it is possible that neoplastic change occurs in a mixture of several types that later differentiate independently into lipoblasts, chondroblasts (osteoblasts), and fibroblasts. This speculation on the pathogenesis would suggest that bone or cartilage can also be formed by neoplastic change. An alternative pathogenesis is that neoplastic change may occur only in the fat cells and that cartilage or bone is then formed by the metaplasia of fibroblasts to chondroblasts (osteoblasts). Katzefl hypothesized from histological observations that cartilage could be developmentally produced in small nodules of fibrous tissue with myxoid and chondroid change by mechanical causes, and that the proximity of lipomas to the periosteum, tendons, or joint capsules might increase the possibility of this type of metaplasia. This hypothesis may be supported by the histopathologic findings in our case in which the cartilage showed a garlandlike shape and had some spaces (Fig 2), suggesting that several small nodules of chondroid substance were growing together and had undergone partial fusion. This concept of the pathogenesis would suggest calling such a
tumor a lipoma with osseous or cartilaginous metaplasia. The synonyms for this variant include chondrolipoma (osteolipoma), lipoma with chondroid (osseous) metaplasia, benign mesenchymoma, harmatoma, and lipoma with cartilaginous (osseous) change. In our opinion, the term lipoma with osseous or cartilaginous change, which does not suggest a pathogenesis but only describes the histological findings, is preferred because the pathogenesis is still inconclusive. References 1. MacGregor AJ, Dyson DP: Oral lipoma. A review of the literature and report of twelve new cases. Oral Surg Oral Med Oral Pathol 21:770, 1966 2. Hatziotis J Ch: Lipomas of the oral cavity. Oral Surg 31:511, 1971 3. de Visscher JGAM: Lipomas and fibrolipomas ofthe oral cavity. J Maxillofac Surg 10: 177, 1982 4. Enzinger FM, Weiss SW: Benign lipomatous tumors, in: Soft Tissue Tumors, (ed 2). St Louis, MO, Mosby, 1988, pp 301345 5. Allen PW: Tumors and Proliferation of Adipose Tissue. New York, NY, Masson, 1981, pp 37-40 6. Katzer B: Histopathology of rare chondroosteoblastic metaplasia in benign lipomas. Path Res Pratt 184:437, 1989 7. Godby AF, Drez PB, Field JL: Sublingual lipoma with ectopic bone formation. Report of a case. Oral Surg Oral Med Oral Pathol 14:625, 1961 8. Hughes CL: Intraoral lipoma with osseous metaplasia. Oral Surg Oral Med Oral Path01 2 1:576,1966 9. McAndrew PG, Greenspan JS: Lipoma of lip with cartilage formation. Br Dent J 140:239, 1976 10. Allard RHB, van der Kwast WAM, Van der Waal I: Oral lipomas with osseous and chondrous metaplasia. Report of two cases. J Oral Path01 11:18, 1982 11. Dutescu N, Georgescu L, Hary M: Lipoma of submandibular space with osseous metaplasia. Report of a case. Oral Surg 35:611, 1973 12. Allen PW: Letters to the case in “Histopathology of rare chondroosteoblastic metaplasia in benign lipomas” (by Katzer, B.). Pathol Res Pratt 184:444. 1989
1015
AND ENOMOTO
rate of growth, and speed of recurrence. When definitive excisional surgery is indicated, the ability to provide functional and esthetic reconstruction is essential. Radiotherapy has not been shown to be effective in treating giant cell jaw lesions.8~‘7 It is inappropriate therapy for benign lesions, especially in children, because of long-term interference with growth and the potential for development of malignancy.4 References
8. 9. IO. 11. 12.
13. 14.
I. Dehner LP: Tumors of the mandible and maxilla in children. I. Clinicopathologic study of 46 histologically benign lesions. Cancer 31:364. 1973 2. Chuong R, Kaban LB: Diagnosis and treatment of jaw tumors in children. J Oral Maxillofac Surg 43:323, 1985 3. Jaffe HL: Giant-cell reparative granuloma, traumatic bone cyst, and fibrous (fibro-osseous) dysplasia of jawbones. Oral Surg 6:159, 1953 4. Austin LT, Dahlin DC, Royer RQ: Giant-cell reparative granuloma and related conditions affecting the jaw bones. Oral Surg Oral Med Oral Path01 12:1285, 1959 5. Waldron CA, Shafer WG: The central giant cell reparative granuloma of the jaws. An analysis of 38 cases. Am J Clin Path01 45:437, 1966 6. Chuong R, Kaban LB, Kozakewich H, et al: Central giant cell lesions of the jaws: A clinicopathologic study. J Oral Maxillofac Surg 44:708, 1986 7. Auclair PL, Cuenin P, Kratochvil FJ, et al: A clinical and histomorphologic comparison of the central giant cell granuloma
J Oral Maxillofac
15. 16.
17. 18. 19.
20.
21.
and the giant cell tumor. Oral Surg Oral Med Oral Path01 66: 197, 1988 Bondi R, Urso C, Santucci B, et al: Giant cell lesion of the jaw. Case report. Tumori 74:479, 1988 Shklar G, Meyer I: Giant-cell tumors of the mandible and maxilla. Oral Sum Oral Med Oral Path01 14:809. 196 1 Small GS, Rowe NH: A “true giant cell tumor” in the mandible? J Oral Surg 33:296, 1975 _ Leban SG. Leoow H. Stratiaos GT. et al: The aiant cell lesion of jaws:‘Neoplastic or reparative’ J Oral Su< 29:398, 197 1 Lucas RB: Giant cell lesions, in Lucas RB (ed): Pathology of Tumors of the Oral Tissues, (ed. 4) Edinburgh, Scotland, Churchill Livingstone, 1983, p 262 Homer K: Central giant cell granuloma of the jaws: A clinicoradiological study. Clin Radio1 40~622, 1989 Som PM, Lawson W. Cohen BA: Giant-cell lesions of the facial bones. Radiology 147:129, I983 Rhea JT, Weber AL: Giant-cell granuloma of the sinuses. Radiology 147:135, 1983 Smith PG, Marrogi AJ, Delfino JJ: Multifocal central giant cell lesions of the maxillofacial skeleton: A case report. J Oral Maxillofac Surg 48:300, 1990 Smith GA, Ward PH: Giant-cell lesions of the facial skeleton. Arch Otolaryngol 104:186, 1978 Quick CA, Anderson R, Stool S: Giant cell tumors ofthe maxilla in children. Laryngoscope 90:784, 1980 Hutter RVP. Worcester JN, Francis KC, et al: Benign and malignant giant cell tumors of bone. A clinicopathological analysis of the natural history of the disease. Cancer 15:653, 1962 Mintz GA, Abrams AM, Carlsen GD, et al: Primary malignant giant cell tumor of the mandible. Report of a case and review of the literature. Oral Surg 5 1:164. 198 1 Andersen L, Fejerskov 0, Philipsen HP: Oral giant cell granulomas. A clinical and histological study of-129 new-cases. Acta Path01 Microbial Stand 8 1:606, 1973
Surg
50:1015-1017,1992
Lipoma of the Tongue With Cartilaginous Change: A Case Report and Review of the Literature N. FUJIMURA,
DDS, PHD,* AND S. ENOMOTO,
Although lipoma can occur in any part of the body, it is infrequently found in the oral cavity.lm3It is a benign lesion composed of mature fat tissue that is arranged in lobules that are separated by septa of fibrous
Received from the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, Tokyo. * Formerly, Instructor; currently, in private practice. 7 Chief and Professor. Address correspondence and reprint requests to Dr Fujimura: Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, 5-45, Yushima, 1-Chome, Bunkyo-ku, Tokyo 113, Japan. 0 1992 American
Association
0278-2391/92/5009-0017$3.00/O
of Oral and Maxillofacial
Surgeons
DDS, PHDt
tissue and surrounded by a thin fibrous capsule. Some variants of lipoma have been classified histologically according to the kind and the amount of the tissue other than fat that is present.294 The most common is fibrolipoma, which contains an increased amount of fibrous connective tissue between the fat cells. Others include angiolipoma with an excess of capillaries, and myxolipoma with wide areas of myxoid change. Lipoma with osseous or cartilaginous change is the rarest variant. Overall, there are 13 cases of this variant that were reviewed by Allen’ and 4 cases presented by Katzer.6 In the oral cavity, only five such lipomas have been reported.‘-” Thus, this case is the sixth intraoral lipoma with osseous or cartilaginous change to be described in the literature.
1016
LIPOMA
OF THE TONGUE
WITH
CARTILAGINOUS
CHANGE
Discussion
FIGURE
1. Mass attached to inferior surface of the tongue.
Report of Case A S-year-old man was seen on July 8, 1983 with a painless mass on the inferior surface of the tongue that the patient had first noted about 2 months previously. The lesion was oval, well-circumscribed, and measured 15 mm X 10 mm. A yellowish tinge was visible through the normal overlying mucosa (Fig 1). On palpation, it was tender and contained a hard central area. The mass was not related to the mandible. Under local anesthesia, the mass was excised, including the overlying mucosa, and the wound was closed primarily. The postoperative course was uneventful. Histologically, the tumor consisted of mature adipose tissue that was thinly encapsulated and two foci of mature cartilage, which were located within the fa%y tissue. The cartilage was surrounded by fibrous tissue that had partly undergone myxoid change. The larger nodule of cartilage had a very irregular outline and a garlandlike shape, as described by Katzer.6 No evidence of neoplastic change was found in the sections examined (Fig 2). The patient was last examined on April 25, 1990 and no recurrence was found.
Osseousor cartilaginous change, which occurs in some types of soft tissue tumors, has rarely been found in lipoma. In the oral and head and neck region, only six such lipomas have been reported. One of these tumors occurred in the submandibular region,’ ’ and the other five occurred in the oral cavity.‘-” The features of intraoral lipomas with osseous or cartilaginous change are summarized from a review of the previous five cases and our case (Table 1). We have investigated whether the reported tumors were related to bone. In the case of the tumor in the sublingual region,’ the lipoma was most likely attached to the periosteum of the genial tubercles of the mandible, because the investigators stated that dissection of the tumor from the periosteum was extremely difficult. Two other tumors located in the mandibular buccal vestibule*,” were adjacent to the mandibular bone or periosteum, although they seemed clinically intact and separate from it, as mentioned by the investigators. The remaining three cases were two tumors of the lower lip9,10and one of the tongue (as described in this report). All contained cartilage and were unrelated to bone. It has been stated that lipomas with osseous or cartilaginous change lying adjacent to bone should be called parosteal or periosteal lipomas to distinguish from those unrelated to bone. It is also suggested that they most likely comprise two separate clinicopathologic entities with a different pathogenesis,12 and that the possibility of osseous or cartilaginous change increases in lipomas located close to bone, periosteum, or joint capsules.6 Some pathologists regard such variant lipomas as benign mesenchymomas, because both adipose and chondroid or osseous components origi-
FIGURE 2. Lipoma with cartilage formation. A, Some foci of mature cartilage with an irregular outline are seen within the fatty tissue (hematoxylin-eosin stain, original magnification X 13). B, Cartilage with spaces occupied by fibrous tissue showing myxoid change (hematoxylineosin stain, original magnification X67).
1017
FUJlMURA
AND ENOMOTO
Table 1.
Intraoral Lipomas With Osseous and Cartilaginous Change Age (Yd
Sex
Godbyet al.’
54
M
Sublingualregion
Hughes’
69
M
Buccal mandibular sulcus
McAndrew et al9
12
M
Lower lip
2.5 x 1.5
Allard et al”
81
F
3.5 x 2
Allard et al” Fujimura & Enomoto
69 56
F M
Buccal mandibular sulcus Lower lip Tongue
1x1 1.5 x 1
Reference
Location
Size (cm)
Duration
7X6X3
1v
3.5 X 2.6 x 1.7
Metaplasia
Relation to Bone
Osseous Osseous
+ 2
6 mo
Cartilaginous
_
30-40 yr
osseous
2
2 yr 2 mo
Cartilaginous Cartilaginous
-
-
1.2X 0.5 x 0.6
nate from mesenchymal tissues.4 However, this term should probably not be applied to those variant lipomas in which adipose tissue predominateq6 or the term could cause confusion. l2 This variant lipoma can be distinguished from an osteocartilaginous choristoma, which commonly occurs in the tongue, because it usually contains less fatty tissue. In addition, the differential diagnosis includes metastatic chondrosarcoma or osteosarcoma, liposarcoma with metaplasia, and posttraumatic chondrification.6 Although the exact origin of the fat cells, chondroblasts, and osteoblasts remains controversial, it is generally accepted that they develop from different types of undifferentiated mesenchymal cells. Therefore, it is possible that neoplastic change occurs in a mixture of several types that later differentiate independently into lipoblasts, chondroblasts (osteoblasts), and fibroblasts. This speculation on the pathogenesis would suggest that bone or cartilage can also be formed by neoplastic change. An alternative pathogenesis is that neoplastic change may occur only in the fat cells and that cartilage or bone is then formed by the metaplasia of fibroblasts to chondroblasts (osteoblasts). Katzefl hypothesized from histological observations that cartilage could be developmentally produced in small nodules of fibrous tissue with myxoid and chondroid change by mechanical causes, and that the proximity of lipomas to the periosteum, tendons, or joint capsules might increase the possibility of this type of metaplasia. This hypothesis may be supported by the histopathologic findings in our case in which the cartilage showed a garlandlike shape and had some spaces (Fig 2), suggesting that several small nodules of chondroid substance were growing together and had undergone partial fusion. This concept of the pathogenesis would suggest calling such a
tumor a lipoma with osseous or cartilaginous metaplasia. The synonyms for this variant include chondrolipoma (osteolipoma), lipoma with chondroid (osseous) metaplasia, benign mesenchymoma, harmatoma, and lipoma with cartilaginous (osseous) change. In our opinion, the term lipoma with osseous or cartilaginous change, which does not suggest a pathogenesis but only describes the histological findings, is preferred because the pathogenesis is still inconclusive. References 1. MacGregor AJ, Dyson DP: Oral lipoma. A review of the literature and report of twelve new cases. Oral Surg Oral Med Oral Pathol 21:770, 1966 2. Hatziotis J Ch: Lipomas of the oral cavity. Oral Surg 31:511, 1971 3. de Visscher JGAM: Lipomas and fibrolipomas ofthe oral cavity. J Maxillofac Surg 10: 177, 1982 4. Enzinger FM, Weiss SW: Benign lipomatous tumors, in: Soft Tissue Tumors, (ed 2). St Louis, MO, Mosby, 1988, pp 301345 5. Allen PW: Tumors and Proliferation of Adipose Tissue. New York, NY, Masson, 1981, pp 37-40 6. Katzer B: Histopathology of rare chondroosteoblastic metaplasia in benign lipomas. Path Res Pratt 184:437, 1989 7. Godby AF, Drez PB, Field JL: Sublingual lipoma with ectopic bone formation. Report of a case. Oral Surg Oral Med Oral Pathol 14:625, 1961 8. Hughes CL: Intraoral lipoma with osseous metaplasia. Oral Surg Oral Med Oral Path01 2 1:576,1966 9. McAndrew PG, Greenspan JS: Lipoma of lip with cartilage formation. Br Dent J 140:239, 1976 10. Allard RHB, van der Kwast WAM, Van der Waal I: Oral lipomas with osseous and chondrous metaplasia. Report of two cases. J Oral Path01 11:18, 1982 11. Dutescu N, Georgescu L, Hary M: Lipoma of submandibular space with osseous metaplasia. Report of a case. Oral Surg 35:611, 1973 12. Allen PW: Letters to the case in “Histopathology of rare chondroosteoblastic metaplasia in benign lipomas” (by Katzer, B.). Pathol Res Pratt 184:444. 1989
