1097
CANDY, KELLER. AND UNNI
findings suggest that retention of unerupted teeth associated with ameloblastic fibro-odontoma may be a useful procedure.
References
1. Slootweg PJ: An analysis of the interrelationship
FIGURE 7. Radiograph taken 2 years after the initial treatment showing the second molar erupted in occlusion and no evidence of recurrent tumor.
rence. In case 2, the lesion was not completely removed at the time of initial treatment. Complete removal of the lesion was accomplished 8 months later. However, the characteristics of the lesion did not change. These
J Oral Maxillofac
of the mixed odontogenic tumor&ameloblr&ic fibroma, ameloblastic fibroodontoma. and the odontomas. Oral Sure 5 1:266, 198 1 2. Hanna RJ, Regezi JA, Hayward JR, et al: Ameloblastic fibroodontoma: Report of case with light and electron microscopic observations. J Oral Surg 34:820, 1976 3. Bemhort CH, Bang G, Gilhuus-Moe 0: Ameloblastic fibroodontoma. Int J Oral Surg 8:241, 1979 4. Miller AS, Lopez CFA, Pullon PA, et al: Ameloblastic fibroodontoma. Oral Surg 41:354, 1976 5. Gardner DC? The mixed odontogenic tumors. Oral Surg 58: 166, 1984 6. Evesole LR. Tomich CE, Chenick HM: Histogenesis of odontogenic tumors. Oral Surg 32:569. 197 1 7. Cahn LR, Blum T: Ameloblastic odontoma: Case report critically analyzed. J Oral Surg 10:169, 1952 8. Phillip LH, Sadeghi EM: Ameioblastic fibro-odontoma: Report of case J Oral Surg 44: 1014, 1986 (letter to the editor) 9. Phillip HH: Ameloblastic fibro-odontoma: Report of a case with documented four-year follow-up. J Oral Surg 40:45, 1982 10. Slootweg PJ: Epithelio-mesenchymal morphology in ameloblastic fibro-odontoma: A light and electron microscopic study. J Oral Path01 9:29, 1980
Surg
50:1097-1102,1992
Ameloblastic Carcinoma: Report of Two Cases STEPHEN
R. GANDY, DMD,* EUGENE E. KELLER, AND K. KRISHNAN UNNI, MBBS$
Received from the Mayo Clinic and Mayo Foundation, Rochester, MN. * Resident in Oral and Maxillofacial Surgery, Mayo Graduate School of Medicine, Rochester, MN. t Consultant, Section of Oral and Maxillofacial Surgery, Mayo Clinic and Mayo Foundation; Associate Professor of Dentistry, Mayo Medical School; Rochester, MN. $ Consultant, Section of Surgical Pathology, Mayo Clinic and Mayo Foundation; Professor of Pathology, Mayo Medical School; Rochester, MN. Address correspondence and reprint requests to Dr Keller: Mayo Clinic, 200 First Street SW, Rochester, MN 55905.
0
1992 American Association of Oral and Maxillofacial
0278-2391/92/5010-0015$3.00/O
Surgeons
DDS, MSD,t
Ameloblastic carcinoma is a rare tumor that challenges the diagnostic acumen of pathologists. It is described as an ameloblastoma in which there is histologic evidence of malignancy in the primary or recurrent tumor, regardless of whether it has metastasized.’ Various classifications have been developed to categorize odontogenic carcinomas.2-4 Initial attempts at classification of these tumors by the World Health Organization failed to specifically delineate ameloblastic carcinoma. Malignant ameloblastoma was considered distinct from other primary intraosseous carcinomas in this system.
1098
AMELOBLASTIC CARCINOMA
FIGURE 1. Pretreatment axial (A) and coronal (B) computed tomographic scans and panoramic radiograph (C). Note cortical thinning, expansion, and perforation of the left mandibular body and ramus. Also note displaced third molar and associated radiolucency.
Elzay’ initially proposed classifying primary jaw intraosseous carcinomas as follows: type 1: arising ex odontogenic cyst; type 2: arising ex ameloblastoma (A) well differentiated (malignant ameloblastoma), (B) poorly differentiated (ameloblastic carcinoma): type 3: arising de novo (A) nonkeratinizing, (B) keratinizing. In this classification, malignant ameloblastoma is differentiated from ameloblastic carcinoma by histologic characteristics rather than clinical behavior. Ameloblastic carcinoma was further recognized and characterized by Slootweg and Miiller,3 who expanded Elzay’s classification by including those ameloblastic carcinomas arising de novo or in association with ameloblastoma or odontogenic cysts. An excellent review of primary ‘intraosseous carcinomas of the jaws can be found in Elzay’s article.* Corio et al’ reported eight cases of ameloblastic carcinoma. The mean age was 30.1 years and no sex or race predisposition was noted. Seven cases involved the mandible and one involved the maxilla, with the
posterior regions favored. Swelling and pain were common presenting symptoms. Maxillary involvement of ameloblastic carcinoma is less frequent than mandibular. In addition to the case previously mentioned,’ single cases of maxillary tumors have been reported.5-8
FIGURE 2. ftndings.
Gross surgical specimen corresponding to radiographic
1099
GANDY, KELLER. AND UNNI
FIGURE 5. lmmunoperoxidase positivity in tumor cells.
stain for keratin shows marked
Report of Cases FIGURE 3. Posttreatment (3% years) radiograph shows composite graft reconstruction of the continuity defect-an> restoration bf the dentition with implants.
Treatment of ameloblastic carcinoma is moot because documented case reports with meaningful followup are rare. Meticulous follow-up is essential because recurrence and metastasis have been reported in the lung and regional lymph nodes.‘.3.7,9Presurgical radiation therapy has been suggested to decrease tumor size.5 Reconstruction of the postresection defect may proceed as in other states post head and neck carcinoma. We believe sufficient time (3 months to 2 years, depending on individual circumstances) should be allotted before reconstruction because of potential tumor recurrence. We present the cases of two patients with ameloblastic carcinoma and their subsequent reconstruction.
FIGURE 4.
Photomicrograph
showing predominantly
spindle-
shaped epithelial cells, but with focal clustering (hematoxylin-eosin stain).
Cuse I A 32-year-old white woman was initially seen by her local dentist because of a complaint of a loose molar in the left
mandible. Radiographs revealed a radiolucent lesion in the left mandibular ramus. A biopsy specimen was obtained and a diagnosis of grade 2 ameloblastic carcinoma was made. The patient was referred to our medical center, where clinical examination revealed an expansile lesion of the left mandibular body and ramus. Radiographically, the lesion was radiolucent, expansile. and cystic with septi and had resorbed a portion of the root of the first molar (Fig 1). The second molar had been removed at the time of biopsy. The patient did not have pain or paresthesia. Palpation of the submandibular space revealed a minimally enlarged, nontender submandibular gland and lymph nodes. The operation was performed under general nasotracheal anesthesia. A partial mandibular resection, including the mandibular left first molar and second premolar, and excision of the left submandibular gland and associated lymph nodes
FIGURE 6. Low-power photomicrograph shows tumor cells in clusters permeating preexisting bony trabeculae (hematoxylin-eosin, original magnification X64).
AMELOBLASTIC CARCINOMA
FIGURE 8. Gross surgicalspecimen showingcondylar involvement by the tumor (top).
FIGURE 7. A. Pretreatment coronal computed tomographic scan and (B) panoramic radiograph. Note left condylar destruction and obliteration of normal osseous contour.
were performed via a submandibular incision (Fig 2). The distal margin of the ostectomy approximated the mental foramen. The proximal osteotomy was via an inverted L osteotomy preserving the coronoid, condyle, and posterior rama1 border to the angle. The submandibular gland and adjacent lymph nodes clinically were not involved by tumor. A Jackson-Pratt drain was placed, the wound was closed in layers, and maxillomandibular fixation was applied. The postoperative course was uneventful. After 8 days, maxillomandibular elastics were placed to control jaw motion. Four months later reconstruction of the continuity defect was accomplished. A titanium mesh tray was placed via a submandibular approach, connecting the proximal and distal segments. Autologous corticocancellous iliac bone was obtained and placed in the tray. The postoperative course was uneventful. Six months later, three osseointegrated implants were inserted in the previously placed bone graft (Fig 3). Uncovering and abutment connection of the endosseous implants were done in 6 months and a prosthesis was fabricated. The patient has been examined every 6 months for 3% years and has remained asymptomatic and free of detectable recurrent disease.
FIGURE 9. Four years postresection and 2 years postreconstruction panoramic radiograph. This shows the ramus and condyle reconstructed with a free vascularized scapular bone graft. There is no clinical or radiographic evidence of recurrent tumor. Fixation plates have been removed.
GANDY.
1101
KELLER, AND UNNI
FlGURE 10. Low-power appearance of ameloblastic carcinoma shows permeation of normal bone (hematoxylin-eosin stain).
The histologic features were predominately spindle-shaped tumor cells with moderate atypia and focal clustering (Fig 4). Immunoperoxidase stain showed a strong positive result for keratin (Fig 5), although results for vimentin and epithelial membrane antigen were negative. The tumor cells formed in distinct clusters and permeated existing bone. Epithelial differentiation with peripheral lining of spaces was found in some areas. Ameloblastoma cell morphology was seen, although the typical palisading arrangement was notably absent (Fig 6).
Case 2 A 20-year-old white man was referred to our clinic for evaluation of a condylar tumor. His local dentist noted a radiolucency of the left mandibular condyle after performing a sialogram of the left parotid gland for evaluation of persistent preauricular swelling. Examination revealed a painless, hard mass involving the left preauricular area and mandibular condyle. The lesion was palpable extraorally in the preauricular area and through
FlGURE 12. High-power appearance of the tumor shows that the cells are more epithelial-appearing and show a tendency to cluster (hematoxylin-eosin stain).
the external auditory meatus. The panoramic radiograph and computed tomographic scans (Fig 7) revealed a destructive lesion of the left condyle. The radiologist could not rule out involvement of the parotid gland. A superficial parotidectomy was performed. The tumor was further isolated through a submandibular incision. A vertical ramus osteotomy was performed posterior to the mandibular foramen, removing the proximal portion of the mandible, including the tumor (Fig 8). The coronoid process and anterior ramus were retained. Routine wound closure and drainage were done. Histologic examination revealed a low-grade ameloblastic carcinoma. The parotid gland and adjacent lymph nodes were not involved by tumor. The patient was followed for 18 months, without evidence of recurrent disease. A mandibular reconstruction using a free vascularized scapular flap was performed without complication. An osseous debulking of the proximal reconstructed mandible was performed 6 months later. The postoperative course was uneventful after each procedure except for persistent limitation of motion, which eventually resolved following active physiotherapy. Four years after tumor resection, there was no evidence of residual disease and jaw function was within normal limits (maximal incisal opening was 43 mm) (Fig 9). Histologically, the tumor showed spindle-shaped cells invading the adjacent normal bone (Fig 10). The tumor cells revealed an ameloblastic pattern with moderate cellular atypia. Some areas of the tumor tended to form in sheets with cells lining the periphery (Fig 11). More definitive epithelial differentiation, with a tendency of the tumor cells to form in clusters. was also seen (Fig 12). Attempted gland formation was a prominent feature of this tumor. Immunoperoxidase, vimentin, and epithelial membrane antigen testing were negative in this case.
Discussion Ameloblastic carcinoma is a rare malignant neoplasm that requires correct histologic diagnosis and agFIGURE 11. Medium-power photomicrograph shows epithelialappearing cells forming sheets (hematoxylin-eosin stain).
gressive surgical therapy. However, reliable evidence of its biological activity is currently lacking due to the
1102
OSTEOCHONDROMA
scarcity of well-documented and adequately followed cases. It occurs primarily in the mandible and in a wide range of age groups. No sex or race predilection is noted. The histologic concept of ameloblastic carcinoma is somewhat vague. The tumor cells resemble the cells seen in ameloblastoma, but they show cytologic atypia. Moreover, they lack the characteristic arrangement seen in ameloblastoma. The clustering arrangement and attempted duct formation support the concept of a carcinoma rather than a sarcoma. The keratin positively seen in one of our cases also supports an epithelial differentiation. We believe that wide local excision is the treatment of choice. Regional lymph node dissection should be considered and performed selectively. Recurrence and metastasis have been reported. Direct extension of the tumor, lymph node involvement, and metastasis to various sites also have been reported. The lung is cited as a frequent location of metastasis. Close periodic reassessment of the patient is mandatory. Differential diagnosis of ameloblastic carcinoma includes various primary and metastatic tumors. Subtypes of typical ameloblastoma, such as the acanthomatous variant, should be considered. Additionally, squamous cell carcinomas arising from an odontogenic
J Oral Maxillofac 50:1102-l
OF THE MANDIBULAR CONDYLE
cyst can be mistaken for ameloblastic carcinoma. Metastatic neoplasms from salivary glands, breast, or lungs may also prove to be histologically similar. References I. Corio RL, Goldblatt LI, Edwards PA, et al: Ameloblastic carcinoma: A clinicopathologic study and assessment of eight cases. Oral Surg Oral Med Oral Path01 64570, 1987 2. Elzay RP: Primary intraosseous carcinoma of the jaws: Review and update of odontogenic carcinomas. Oral Surg Oral Med Oral Path01 54:299, 1982 3. Slootweg PJ, Miiller H: Malignant ameloblastoma or ameloblastic carcinoma. Oral Surg Oral Med Oral Pathol 57: 168, 1984 4. Pindborg JJ, Kramer IRH, Torloni H: Histological Typing of Odontogenic Tumours, Jaw Cysts, and Allied Lesions, International Histological Classification of Turnours, No. 5. Geneva, World Health Organization, 197 1, p 35 5. Andersen E, Bang G: Ameloblastic carcinoma of the maxilla: A case report. J Maxillofac Surg 14:338, 1986 6. McClatchey KD, Sullivan MJ, Paugh DR: Peripheral ameloblastic carcinoma: A case report of a rare neoplasm. J Otolaryngol 18:109, 1989 7. Lee L, Maxymiw WG, Wood RE: Ameloblastic carcinoma of the maxilla metastatic to the mandible: Case report. J Craniomaxillofac Surg 18:247, 1990 8. Nadimi H. Toto PD, Jaffe E. et al: Basement membrane defect in ameloblastic carcinoma: A case study. J Oral Med 41:79, 1986 9. Dorner L, Sear AJ, Smith GT: A case of ameloblastic carcinoma with pulmonary metastases. Br J Oral Maxillofac Surg 26: 503, 1988
Surg
108, 1992
Osteochondroma of the Mandibular Condyle: Report of a Case and Review of the Literature CHARLES
H. HENRY, DDS,* EDWIN L. GRANITE, AND LOUIS K. RAFETTO, DMD$
Osteochondroma, or osteocartilagenous exostosis, is an exophytic lesion that arises from the cortex of bone and is cartilage-capped.’ It is one of the most common benign tumors of the axial skeleton. Osteochondroma comprised 35.8% of the benign tumors in Dahlin’s re-
Received from the Medical Center of Delaware, Wilmington, DE. * Former Chief Resident, Section of Oral and Maxillofacial Surgery; in private practice, Keene, NH. t Senior Attending, Section of Oral and Maxillofacial Surgery. $ Director of Graduate Training Program in Oral and Maxillofacial Surgery. Address correspondence and reprint requests to Dr Henry: 650 Court St, Keene, NH 0343 I. 0 1992
American
0278-2391/92/501
Association
of Oral and Maxillofacial
O-001 6$3.00/O
Surgeons
DDS,t
view of primary bone tumors, and 8.5% of the total number of tumors in the series.’ An osteochondroma of the facial skeleton, however, is a rare occurrence. Most commonly, the tumor has been reported associated with the coronoid process. A review of the extracondylar osteochondromas of the jaws was done by Brady et al3 They found 18 reported cases of osteochondroma of the coronoid process acceptable for inclusion in their review based on histologic criteria. They presented two additional cases of extracondylar osteochrondromas, one of the body of the mandible and the other of the maxilla. Osteochondroma of the zygomatic arch and maxillary sinus has also been reported.4-6 Osteochondroma of the mandibular condyle is extremely rare. Forssell et al have reviewed 26 reported cases and added one additional case.’ After a review
CANDY, KELLER. AND UNNI
findings suggest that retention of unerupted teeth associated with ameloblastic fibro-odontoma may be a useful procedure.
References
1. Slootweg PJ: An analysis of the interrelationship
FIGURE 7. Radiograph taken 2 years after the initial treatment showing the second molar erupted in occlusion and no evidence of recurrent tumor.
rence. In case 2, the lesion was not completely removed at the time of initial treatment. Complete removal of the lesion was accomplished 8 months later. However, the characteristics of the lesion did not change. These
J Oral Maxillofac
of the mixed odontogenic tumor&ameloblr&ic fibroma, ameloblastic fibroodontoma. and the odontomas. Oral Sure 5 1:266, 198 1 2. Hanna RJ, Regezi JA, Hayward JR, et al: Ameloblastic fibroodontoma: Report of case with light and electron microscopic observations. J Oral Surg 34:820, 1976 3. Bemhort CH, Bang G, Gilhuus-Moe 0: Ameloblastic fibroodontoma. Int J Oral Surg 8:241, 1979 4. Miller AS, Lopez CFA, Pullon PA, et al: Ameloblastic fibroodontoma. Oral Surg 41:354, 1976 5. Gardner DC? The mixed odontogenic tumors. Oral Surg 58: 166, 1984 6. Evesole LR. Tomich CE, Chenick HM: Histogenesis of odontogenic tumors. Oral Surg 32:569. 197 1 7. Cahn LR, Blum T: Ameloblastic odontoma: Case report critically analyzed. J Oral Surg 10:169, 1952 8. Phillip LH, Sadeghi EM: Ameioblastic fibro-odontoma: Report of case J Oral Surg 44: 1014, 1986 (letter to the editor) 9. Phillip HH: Ameloblastic fibro-odontoma: Report of a case with documented four-year follow-up. J Oral Surg 40:45, 1982 10. Slootweg PJ: Epithelio-mesenchymal morphology in ameloblastic fibro-odontoma: A light and electron microscopic study. J Oral Path01 9:29, 1980
Surg
50:1097-1102,1992
Ameloblastic Carcinoma: Report of Two Cases STEPHEN
R. GANDY, DMD,* EUGENE E. KELLER, AND K. KRISHNAN UNNI, MBBS$
Received from the Mayo Clinic and Mayo Foundation, Rochester, MN. * Resident in Oral and Maxillofacial Surgery, Mayo Graduate School of Medicine, Rochester, MN. t Consultant, Section of Oral and Maxillofacial Surgery, Mayo Clinic and Mayo Foundation; Associate Professor of Dentistry, Mayo Medical School; Rochester, MN. $ Consultant, Section of Surgical Pathology, Mayo Clinic and Mayo Foundation; Professor of Pathology, Mayo Medical School; Rochester, MN. Address correspondence and reprint requests to Dr Keller: Mayo Clinic, 200 First Street SW, Rochester, MN 55905.
0
1992 American Association of Oral and Maxillofacial
0278-2391/92/5010-0015$3.00/O
Surgeons
DDS, MSD,t
Ameloblastic carcinoma is a rare tumor that challenges the diagnostic acumen of pathologists. It is described as an ameloblastoma in which there is histologic evidence of malignancy in the primary or recurrent tumor, regardless of whether it has metastasized.’ Various classifications have been developed to categorize odontogenic carcinomas.2-4 Initial attempts at classification of these tumors by the World Health Organization failed to specifically delineate ameloblastic carcinoma. Malignant ameloblastoma was considered distinct from other primary intraosseous carcinomas in this system.
1098
AMELOBLASTIC CARCINOMA
FIGURE 1. Pretreatment axial (A) and coronal (B) computed tomographic scans and panoramic radiograph (C). Note cortical thinning, expansion, and perforation of the left mandibular body and ramus. Also note displaced third molar and associated radiolucency.
Elzay’ initially proposed classifying primary jaw intraosseous carcinomas as follows: type 1: arising ex odontogenic cyst; type 2: arising ex ameloblastoma (A) well differentiated (malignant ameloblastoma), (B) poorly differentiated (ameloblastic carcinoma): type 3: arising de novo (A) nonkeratinizing, (B) keratinizing. In this classification, malignant ameloblastoma is differentiated from ameloblastic carcinoma by histologic characteristics rather than clinical behavior. Ameloblastic carcinoma was further recognized and characterized by Slootweg and Miiller,3 who expanded Elzay’s classification by including those ameloblastic carcinomas arising de novo or in association with ameloblastoma or odontogenic cysts. An excellent review of primary ‘intraosseous carcinomas of the jaws can be found in Elzay’s article.* Corio et al’ reported eight cases of ameloblastic carcinoma. The mean age was 30.1 years and no sex or race predisposition was noted. Seven cases involved the mandible and one involved the maxilla, with the
posterior regions favored. Swelling and pain were common presenting symptoms. Maxillary involvement of ameloblastic carcinoma is less frequent than mandibular. In addition to the case previously mentioned,’ single cases of maxillary tumors have been reported.5-8
FIGURE 2. ftndings.
Gross surgical specimen corresponding to radiographic
1099
GANDY, KELLER. AND UNNI
FIGURE 5. lmmunoperoxidase positivity in tumor cells.
stain for keratin shows marked
Report of Cases FIGURE 3. Posttreatment (3% years) radiograph shows composite graft reconstruction of the continuity defect-an> restoration bf the dentition with implants.
Treatment of ameloblastic carcinoma is moot because documented case reports with meaningful followup are rare. Meticulous follow-up is essential because recurrence and metastasis have been reported in the lung and regional lymph nodes.‘.3.7,9Presurgical radiation therapy has been suggested to decrease tumor size.5 Reconstruction of the postresection defect may proceed as in other states post head and neck carcinoma. We believe sufficient time (3 months to 2 years, depending on individual circumstances) should be allotted before reconstruction because of potential tumor recurrence. We present the cases of two patients with ameloblastic carcinoma and their subsequent reconstruction.
FIGURE 4.
Photomicrograph
showing predominantly
spindle-
shaped epithelial cells, but with focal clustering (hematoxylin-eosin stain).
Cuse I A 32-year-old white woman was initially seen by her local dentist because of a complaint of a loose molar in the left
mandible. Radiographs revealed a radiolucent lesion in the left mandibular ramus. A biopsy specimen was obtained and a diagnosis of grade 2 ameloblastic carcinoma was made. The patient was referred to our medical center, where clinical examination revealed an expansile lesion of the left mandibular body and ramus. Radiographically, the lesion was radiolucent, expansile. and cystic with septi and had resorbed a portion of the root of the first molar (Fig 1). The second molar had been removed at the time of biopsy. The patient did not have pain or paresthesia. Palpation of the submandibular space revealed a minimally enlarged, nontender submandibular gland and lymph nodes. The operation was performed under general nasotracheal anesthesia. A partial mandibular resection, including the mandibular left first molar and second premolar, and excision of the left submandibular gland and associated lymph nodes
FIGURE 6. Low-power photomicrograph shows tumor cells in clusters permeating preexisting bony trabeculae (hematoxylin-eosin, original magnification X64).
AMELOBLASTIC CARCINOMA
FIGURE 8. Gross surgicalspecimen showingcondylar involvement by the tumor (top).
FIGURE 7. A. Pretreatment coronal computed tomographic scan and (B) panoramic radiograph. Note left condylar destruction and obliteration of normal osseous contour.
were performed via a submandibular incision (Fig 2). The distal margin of the ostectomy approximated the mental foramen. The proximal osteotomy was via an inverted L osteotomy preserving the coronoid, condyle, and posterior rama1 border to the angle. The submandibular gland and adjacent lymph nodes clinically were not involved by tumor. A Jackson-Pratt drain was placed, the wound was closed in layers, and maxillomandibular fixation was applied. The postoperative course was uneventful. After 8 days, maxillomandibular elastics were placed to control jaw motion. Four months later reconstruction of the continuity defect was accomplished. A titanium mesh tray was placed via a submandibular approach, connecting the proximal and distal segments. Autologous corticocancellous iliac bone was obtained and placed in the tray. The postoperative course was uneventful. Six months later, three osseointegrated implants were inserted in the previously placed bone graft (Fig 3). Uncovering and abutment connection of the endosseous implants were done in 6 months and a prosthesis was fabricated. The patient has been examined every 6 months for 3% years and has remained asymptomatic and free of detectable recurrent disease.
FIGURE 9. Four years postresection and 2 years postreconstruction panoramic radiograph. This shows the ramus and condyle reconstructed with a free vascularized scapular bone graft. There is no clinical or radiographic evidence of recurrent tumor. Fixation plates have been removed.
GANDY.
1101
KELLER, AND UNNI
FlGURE 10. Low-power appearance of ameloblastic carcinoma shows permeation of normal bone (hematoxylin-eosin stain).
The histologic features were predominately spindle-shaped tumor cells with moderate atypia and focal clustering (Fig 4). Immunoperoxidase stain showed a strong positive result for keratin (Fig 5), although results for vimentin and epithelial membrane antigen were negative. The tumor cells formed in distinct clusters and permeated existing bone. Epithelial differentiation with peripheral lining of spaces was found in some areas. Ameloblastoma cell morphology was seen, although the typical palisading arrangement was notably absent (Fig 6).
Case 2 A 20-year-old white man was referred to our clinic for evaluation of a condylar tumor. His local dentist noted a radiolucency of the left mandibular condyle after performing a sialogram of the left parotid gland for evaluation of persistent preauricular swelling. Examination revealed a painless, hard mass involving the left preauricular area and mandibular condyle. The lesion was palpable extraorally in the preauricular area and through
FlGURE 12. High-power appearance of the tumor shows that the cells are more epithelial-appearing and show a tendency to cluster (hematoxylin-eosin stain).
the external auditory meatus. The panoramic radiograph and computed tomographic scans (Fig 7) revealed a destructive lesion of the left condyle. The radiologist could not rule out involvement of the parotid gland. A superficial parotidectomy was performed. The tumor was further isolated through a submandibular incision. A vertical ramus osteotomy was performed posterior to the mandibular foramen, removing the proximal portion of the mandible, including the tumor (Fig 8). The coronoid process and anterior ramus were retained. Routine wound closure and drainage were done. Histologic examination revealed a low-grade ameloblastic carcinoma. The parotid gland and adjacent lymph nodes were not involved by tumor. The patient was followed for 18 months, without evidence of recurrent disease. A mandibular reconstruction using a free vascularized scapular flap was performed without complication. An osseous debulking of the proximal reconstructed mandible was performed 6 months later. The postoperative course was uneventful after each procedure except for persistent limitation of motion, which eventually resolved following active physiotherapy. Four years after tumor resection, there was no evidence of residual disease and jaw function was within normal limits (maximal incisal opening was 43 mm) (Fig 9). Histologically, the tumor showed spindle-shaped cells invading the adjacent normal bone (Fig 10). The tumor cells revealed an ameloblastic pattern with moderate cellular atypia. Some areas of the tumor tended to form in sheets with cells lining the periphery (Fig 11). More definitive epithelial differentiation, with a tendency of the tumor cells to form in clusters. was also seen (Fig 12). Attempted gland formation was a prominent feature of this tumor. Immunoperoxidase, vimentin, and epithelial membrane antigen testing were negative in this case.
Discussion Ameloblastic carcinoma is a rare malignant neoplasm that requires correct histologic diagnosis and agFIGURE 11. Medium-power photomicrograph shows epithelialappearing cells forming sheets (hematoxylin-eosin stain).
gressive surgical therapy. However, reliable evidence of its biological activity is currently lacking due to the
1102
OSTEOCHONDROMA
scarcity of well-documented and adequately followed cases. It occurs primarily in the mandible and in a wide range of age groups. No sex or race predilection is noted. The histologic concept of ameloblastic carcinoma is somewhat vague. The tumor cells resemble the cells seen in ameloblastoma, but they show cytologic atypia. Moreover, they lack the characteristic arrangement seen in ameloblastoma. The clustering arrangement and attempted duct formation support the concept of a carcinoma rather than a sarcoma. The keratin positively seen in one of our cases also supports an epithelial differentiation. We believe that wide local excision is the treatment of choice. Regional lymph node dissection should be considered and performed selectively. Recurrence and metastasis have been reported. Direct extension of the tumor, lymph node involvement, and metastasis to various sites also have been reported. The lung is cited as a frequent location of metastasis. Close periodic reassessment of the patient is mandatory. Differential diagnosis of ameloblastic carcinoma includes various primary and metastatic tumors. Subtypes of typical ameloblastoma, such as the acanthomatous variant, should be considered. Additionally, squamous cell carcinomas arising from an odontogenic
J Oral Maxillofac 50:1102-l
OF THE MANDIBULAR CONDYLE
cyst can be mistaken for ameloblastic carcinoma. Metastatic neoplasms from salivary glands, breast, or lungs may also prove to be histologically similar. References I. Corio RL, Goldblatt LI, Edwards PA, et al: Ameloblastic carcinoma: A clinicopathologic study and assessment of eight cases. Oral Surg Oral Med Oral Path01 64570, 1987 2. Elzay RP: Primary intraosseous carcinoma of the jaws: Review and update of odontogenic carcinomas. Oral Surg Oral Med Oral Path01 54:299, 1982 3. Slootweg PJ, Miiller H: Malignant ameloblastoma or ameloblastic carcinoma. Oral Surg Oral Med Oral Pathol 57: 168, 1984 4. Pindborg JJ, Kramer IRH, Torloni H: Histological Typing of Odontogenic Tumours, Jaw Cysts, and Allied Lesions, International Histological Classification of Turnours, No. 5. Geneva, World Health Organization, 197 1, p 35 5. Andersen E, Bang G: Ameloblastic carcinoma of the maxilla: A case report. J Maxillofac Surg 14:338, 1986 6. McClatchey KD, Sullivan MJ, Paugh DR: Peripheral ameloblastic carcinoma: A case report of a rare neoplasm. J Otolaryngol 18:109, 1989 7. Lee L, Maxymiw WG, Wood RE: Ameloblastic carcinoma of the maxilla metastatic to the mandible: Case report. J Craniomaxillofac Surg 18:247, 1990 8. Nadimi H. Toto PD, Jaffe E. et al: Basement membrane defect in ameloblastic carcinoma: A case study. J Oral Med 41:79, 1986 9. Dorner L, Sear AJ, Smith GT: A case of ameloblastic carcinoma with pulmonary metastases. Br J Oral Maxillofac Surg 26: 503, 1988
Surg
108, 1992
Osteochondroma of the Mandibular Condyle: Report of a Case and Review of the Literature CHARLES
H. HENRY, DDS,* EDWIN L. GRANITE, AND LOUIS K. RAFETTO, DMD$
Osteochondroma, or osteocartilagenous exostosis, is an exophytic lesion that arises from the cortex of bone and is cartilage-capped.’ It is one of the most common benign tumors of the axial skeleton. Osteochondroma comprised 35.8% of the benign tumors in Dahlin’s re-
Received from the Medical Center of Delaware, Wilmington, DE. * Former Chief Resident, Section of Oral and Maxillofacial Surgery; in private practice, Keene, NH. t Senior Attending, Section of Oral and Maxillofacial Surgery. $ Director of Graduate Training Program in Oral and Maxillofacial Surgery. Address correspondence and reprint requests to Dr Henry: 650 Court St, Keene, NH 0343 I. 0 1992
American
0278-2391/92/501
Association
of Oral and Maxillofacial
O-001 6$3.00/O
Surgeons
DDS,t
view of primary bone tumors, and 8.5% of the total number of tumors in the series.’ An osteochondroma of the facial skeleton, however, is a rare occurrence. Most commonly, the tumor has been reported associated with the coronoid process. A review of the extracondylar osteochondromas of the jaws was done by Brady et al3 They found 18 reported cases of osteochondroma of the coronoid process acceptable for inclusion in their review based on histologic criteria. They presented two additional cases of extracondylar osteochrondromas, one of the body of the mandible and the other of the maxilla. Osteochondroma of the zygomatic arch and maxillary sinus has also been reported.4-6 Osteochondroma of the mandibular condyle is extremely rare. Forssell et al have reviewed 26 reported cases and added one additional case.’ After a review
