ANa OIollUtUool ~ 101:11182
CHONDROBLASTOMA OF THE TEMPORAL BONE CASE REPORT AND LITERATURE REVIEW MARK A. VARV ARES, MD MACK L. CHENEY, MD EMILY CEISLER, MD
MAx L. GooDMAN, MD
WILLIAM W. MONTGOMERY, MD BOSTON. MAsSACHUSETTS
Chondroblastoma is a rare tumor of bone that represents approximately 1% of all primary bone tumors. In the temporal bone. only 33 have been reported. We present a case of chondroblastoma of the temporal bone. followed by a literature review and analysis of reported cases. We conclude that the best chance for a prolonged disease-free interval is total excision using a combined otolaryngologic and neurosurgical approach. KEY WORDS -
chondroblastoma, connective tissue neoplasms. temporal bone. INTRODUcnON
oral analgesics. Eventually, a computed tomography (Cf) scan was done that showed a large lesion of the right petrous bone with extension into the middle cranial and infratemporal fossae (Fig I). The lesion in the right external auditory canal was again submitted to biopsy, this time with a diagnosis of chondroblastoma. He was then referred to the senior author (W.W.M.)
Benign chondroblastoma is a rare tumor of bone that represents approximately I % ofall primary bone tumors. These tumors are most commonly found arising in the epiphysis ofa long bone, with the femur, humerus, and tibia being the most commonly affected.! Primary bone tumors of the cranial bones are considered rare, comprising 2% of all primary bone tumors.s A chondroblastoma of the temporal bone is an even rarer entity, with only 32 cases having been reported previously.lU
At presentation, the patient complained of severe right-sided otalgia. Physical examination revealed a tender swelling over the right temporal and preauricular area. The right external auditory canal was occluded by a tumor. The patient's Weber examination lateralized to the left. The remainder of the findings on neurotologic examination, including cranial nerves, were unremarkable. Examination of the oral cavity showed painful trismus. The remainder of his head and neck examination was without evidence of any other masses. An audiogram was obtained that was essentially normal.
We now present a case of chondroblastoma of the temporal bone that was referred for definitive treatment. Included is a comprehensive review ofall cases reported to date, including symptoms, physical examination findings, radiographic data, treatment modalities, and outcome. CASE REPORT
A 33-year-old man presented with a l-year history of right-sided otalgia. Subsequently. he developed decreased hearing on the right with progressive dysequilibrium and headache. A slowly enlarging mass was noted in his right temporal area.
A magnetic resonance imaging (MRI) scan was performed and showed a large extradural lesion ofthe right petrous bone, with extension into the middle and infratemporal fossae. A preoperative cerebral arteriogram was consistent with an avascular mass without carotid compression or displacement.
Initial evaluation at an outside institution revealed a mass in his right external auditory canal. A biopsy yielded diagnosis ofgranulation tissue. He was treated with enteral antibiotics, but noted no improvement in his symptoms. He then underwent treatment for presumed temporomandibular joint dysfunction with
Upon consideration of the tumor location, a combined one-stage procedure with neurosurgery was planned. In the operating room the patient was prepared for an intracranial-extradural, transcervicaltransmastoid surgical approach with an extended parotidectomy incision that extended superiorly well
From the Department of Otolaryngology. Massachusetts Eye and Ear Infirmary. Harvard Medical School, Boston, Massachusetts. REPRINTS - William W. Montgomery, MD, Dept of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles 51,Boston, MA 02114.
763
764
Varvares et al, Temporal Bone Chondroblastoma
Fig 1. Contrast-enhanced computed tomograms of right temporal bone showing extent of bone destruction and encroachment of lesion on middle cranial fossa. A) Axial. B) Coronal.
into the temporal fossa and inferiorly into the neck along the anterior border of the sternocleidomastoid muscle (Fig 2A). As an initial maneuver, the common carotid artery and internal jugular vein were isolated so as to obtain proximal vascular control. An anterior skin flap was elevated over the parotid and the external auditory canal was transected and oversewn. The facial nerve was isolated at the stylomastoid foramen. A superficial parotidectomy was performed and the entire extratemporal facial nerve was identified and preserved. The lateral extent of the tumor was identified deep to the facial nerve. The mastoid cortex was exposed and a wide field mastoidectomy was performed. This exposure allowed the intratemporal portion of the tumor to be identified. The facial nerve was dissected as far as the geniculate ganglion. A middle fossa craniotomy was required to visualize the intracranial tumor. The medial resection margins and the labyrinthine portion of the facial nerve were fully visualized. During the extradural dissection, it was noted that the tumor was adherent to the dura but was able to be dissected free. As a final step in the resection, the zygomatic arch was transected. The condyle of the mandible and the infratemporal fossa contents were freed and the tumor was able to be delivered essentially en bloc. After hemostasis was obtained, a 6 x 6-cm tissue defect remained. This area included open air cells of the temporal bone, the internal auditory canal and associated nerves, and the trigeminal nerve (Fig 2B). A large fat graft harvested from the abdomen was used to obliterate the defect (Fig 2C). The wound was then closed in layers and drained. At the conclusion of the operation and just prior to wound closure, stimulation of the seventh cranial nerve at the internal auditory canal showed it
to be intact. Postoperatively, the patient recovered well. There was no evidence of cerebrospinal fluid leak, and the preoperative pain was relieved. The patient developed a temporary facial paresis that improved. An MRI scan with gadolinium and CT performed 2 years postoperatively revealed no evidence of recurrent or residual disease (Fig 3). Pathology examinations of the resected tissue showed a chondroblastoma tumor involving the temporomandibular joint, petrous temporal bone, and bony ear canal with nodular extensions into soft tissues. Histologically, the cellular features were characteristic of chondroblastoma neoplasms (Fig 4). LITERATURE REVIEW
Thirty-two cases of chondroblastoma of the bony ear canal with extensions into temporal bone have been reported, and 29 had detailed data. 1- lO,12,13 The 29 patients with detailed data and our patient are represented in the discussions.
Age and Sex Distribution. The ages of patients reported ranged from 2.9 years to 70 years of age. If the patient that was 2.9 years of age is excluded, the median age within the group was 43.8 years. The sex incidence was 21 males and 9 females for a male to female ratio of 2.3: 1. The age range for the males was 16 to 66 years, and for the females it was 2.9 to 70 years.
Presenting Symptoms. Twenty-six patients had a detailed description of presenting symptoms. The
Varvares et al, Temporal Bone Chondroblastoma
765
Fig 2. Surgical procedure. A) Outline of incision. B) Surgical defect. 1- sigmoid sinus. 2 - parotid gland. 3 - middle fossa dura. C) Obliterated surgical defect with adipose graft.
766
Varvares et al, Temporal Bone Chondroblastoma
766
TABLE 1. PRESENTING SYMPTOMS
Symptoms Hearing loss Otalgia Tinnitus Mass Vertigo or dysequilibrium Aural fullness or blocked ear Headache Seizures Pain Temporomandibular joint arthralgia or dysfunction Coma Facial numbness
Fig 3. Axial computed tomogram showing obliterated surgical defect and no evidence of recurrent disease.
most frequent presenting symptoms are listed in Table 1. Symptoms that were most prominent were hearing loss, otalgia, tinnitus, and a mass sensation in the ear. Most patients averaged two of the listed presenting symptoms, with a range of one to five. The average duration of symptoms prior to seeking medical attention was 12.5 months, although one patient reportedly had symptoms for 30 years; the range was from 2 months to 30 years.
No. of Pts 13 8 6 5 5 4 4 2 1
Physical Findings. Fourteen of the 29 patients had documented physical findings. The physical findings, in order of decreasing frequency, and the number of patients with each finding are listed in Table 2. The predominant alteration was a mass in the external auditory canal. Radiographic Data. Radiographic examinations reflected equipment available at the time ofpresentation. These include plain films, tomograms, CT, and MRI. Eight patients had plain films performed. The temporal bone lesions were described as osteolytic (two patients), destructive (two), cystic (two), erosive (one), and multichambered with marginal sclerosis (one). Five patients had tomograms, with the lesions described as normal (one), destructive (three), and erosive (one). Eight patients had CT performed. The lesions were described as soft tissue with spotty central calcifications (one), normal (one), soft tissue
Fig 4. Photomicrograph of resected tissue.
Varvares et al, Temporal Bone Chondroblastoma
TABLE 2. EXAMINATION FINDINGS Findings
Mass in external auditory canal Nontender temporal mass Tender temporal mass Papilledema Altered mental status Tenderness Trismus Nystagmus
TABLE 4. COMPLICATIONS IN FIVE PATIENTS
Patients (N
= 14)
No.
% 71
10 3 2 2
2 1 1 1
767
Complication
Type of Treatment Used
Conductive hearing loss Temporary cerebrospinal fluid leak, deafness, facial paralysis Temporary facial paralysis Radionecrosis of auricular cartilage requiring amputation Hearing loss
21 14 14 14 7 7 7
Total excision Total excision Total excision Radiotherapy (64 Gy) Total excision and radiotherapy (60 Gy)
DISCUSSION
mass with intracranial shift (two), lytic lesion (one), sharply demarcated solitary sclerotic lesion (one), destructive (one), and expansile (two). Two patients had MRI performed. Both of these lesions were reported as an expansile mass within the temporal bone.
Chondroblastoma, a rare tumor, represents less than 1% of primary bone tumorsl! and occurs predominantly in the epiphyseal area of long bones. They are more common in the second decade, with a male to female ratio of approximately 2:1.
Five patients had preoperative arteriograms. One showed a tumor blush, and the rest showed no evidence of a vascular mass.
The temporal bone chondroblastoma presents at an older age than other sites, with an average of 43.8 years. The male to female ratio is 2:1.
Treatment. The treatment modalities in the previously reported cases were total en bloc excision, curettage, irradiation, and irradiation combined with surgical excision. The most effective modality appears to be total excision with or without irradiation. The number of patients in each group, as well as the length of follow-up and the presence or absence of recurrence, is listed in Table 3.
The pathogenesis of chondroblastoma is uncertain. In long bones, it has been suggested that the chondroblastoma originates from the cells of the endochondral plate. Another theory proposes origin from reticulohistiocytes or related cells. Electron microscopic studies have concluded development from "normal cartilage cells to an altered local environment rather than an intrinsic alteration of cartilage cells per se."II(p33) Other electron microscopic studies have concluded origin from cartilage-forming matrix cells. I I
Complications of Treatment. Five patients had complications, and they are listed in Table 4, along with the initial type of treatment used. Hearing loss was the predominant complication. There have been reports of postirradiation sarcoma for treatments of other tumors and chondroblastomas in other sites, but this has not occurred in temporal bone chondroblastoma treatments. 14- 16 Metastatic chondroblastoma from the temporal bone has not been reported. 15,16
The endochondral origin for portions of the temporal bone and the potential for rests of cartilaginous cells may allow this lesion to develop, with the appropriate initiating event. Similar theories have been proposed for the development of chondrosarcoma, which may arise de novo in the temporal
TABLE 3. TREATMENT GROUPS
Treatment Total en bloc excision
Curettage or incomplete excision Radiotherapy (64 Gy) Curettage and postoperative radiotherapy (20 Gy) Total excision with preoperative (1 pt) or postoperative (2 pts) radiotherapy (60 Gy)
8
No.ofPts With Follow-up 7
13
10
0-9 y (average, 3.4 y)
9/lOt
1 1
1 1
3
3
8.5 Y 4.5 Y 0-9y (average, 7.5 y)
1/1 1/1 3/3§
No. of Pts
NED - with no evidence of disease. *One patient had curettage I month before total excision. tFour patients required two procedures because of recurrent or residual disease. §One patient had incomplete removal II months before complete excision.
Length of Follow-up
No.ofPts NED
0-63 mo (average, 21 mo)
7n*
768
Varvares et al, Temporal Bone Chondroblastoma
bone.l7 Temporal bone chondroblastoma malignancy has not been reported,15,16 secondary to irradiation or in the form of metastasis.14-16 The number of chondroblastoma patients receiving irradiation is small, and the potential for malignant transformation may not be adequately formulated. The primary presenting symptoms were predominantly otologic, with hearing loss being the most common. This was followed in decreasing frequency by otalgia, tinnitus, mass lesions, dysequilibrium, aural fullness, and headache, as well as other, less common complaints. These symptoms are all consistent with a slowly enlarging lesion of the temporal bone. The benign nature of this lesion is supported by the delay in presentation ofthe patients. Most patients had symptoms that had developed 1 year prior to seeking medical attention. The most common finding on physical examination was a mass, either in the external auditory canal or in the temporal area. A small percentage of patients presented with increased intracranial pressure as a result of their tumor, manifested as papilledema, altered mental status, or coma. The radiographic modalities used to evaluate these lesions were based primarily on the techniques available at the time of presentation. Earlier studies used primarily plain films and tomograms, whereas the later series used both CT and MR!. It is our opinion that CT allows clear delineation of the extent of bony destruction and MR! shows the tumor-dura interface and aids in determining if the tumor has remained extradural. Cerebral arteriography may be required for assessment of invasion or displacement of the internal carotid artery, or of tumor vascularity, and facilitates balloon test occlusion of the ipsilateral internal carotid artery should there be concern over possible sacrifice of this vessel. The reviewed cases of chondroblastoma of the temporal bone show that any of the modalities used thus far in the treatment may result in a prolonged disease-free interval. The data indicate that initial curettage of the lesion results in recurrences requiring secondary procedures before attaining a diseasefree interval. Patients who underwent an en bloc
resection or total excision of tumor had no evidence of recurrence at an average follow-up of 27 months. Irradiation used alone or in combination with curettage or total excision was equally effective in the small number of patients treated with it. It is evident that en bloc removal of tumor with the possibility of multiple cranial nerve deficits is not essential to obtaining a prolonged disease-free interval. Total excision of all gross tumor with careful preservation of the important neurovascular structures at the skull base should be adequate treatment for this benign lesion. This is attainable with the present surgical skills and approaches to skull base surgery. Radiotherapy is not recommended for this lesion. Our approach with this patient and to similar lesions of the temporal bone is as follows. After a complete history is taken, physical and neurotologic examinations are performed with radiographic and angiographic evaluations. Surgery is a combined procedure with neurosurgery. A transmastoid-transcervical approach by the otolaryngology team allows early control of the major vascular structures at the skull base, and the isolation of the tumor at the skull base with its intratemporal component. The neurosurgery team performs a temporal craniotomy using an extradural approach to obtain superior and medial margins and visualization of tumor and the critical structures in the middle fossa. This combined approach allows for relatively safe removal of all gross tumor while preserving the major neurovascular structures of the skull base. Adipose obliteration of the operative cavity with watertight closure helps to prevent postoperative cerebrospinal fluid leak. If the tumor cannot be removed from the dura with the dura remaining intact, this portion ofdura may be resected and reconstructed with fascia lata or irradiated homograft dura.? SUMMARY
A case ofchondroblastoma of the temporal bone is presented with a literature review of similar cases. The appropriate treatment appears to be a combined otolaryngologic-neurosurgical excision after proper clinical and radiographic evaluations to allow the total excision of the tumor with minimal morbidity.
REFERENCES I. Dahlin DC. Irving Jc. Benign chondroblastoma: a study of 125 cases. Cancer 1972;30:401-13.
sa.
2. Harner Cody DTR. Dahlin DC. Benign chondroblastoma of the temporal bone. Otolaryngol Head Neck Surg 1979; 87:229-36. 3. Anim IT, Baraka ME. Chondroblastoma of temporal bone: unusual histologic features. Ann Otol Rhinol Laryngol
1986;95:260-3.
a.
4. Blaauw Prick JJW. Versteege C. Chondroblastoma of the temporal bone. Neurosurgery 1988;22:1102-7. 5. Bertoni F, Unni KK. Beabout JW, Harner SF, Dahlin DC. Chondroblastoma ofthe skull and facial bones. Am J Clin Pathol 1987;88:1-9. 6. Cares HL. Terplan K. Chondroblastoma of the skull: case
Varvares et al, Temporal Bone Chondroblastoma report. J Neurosurg 1971;35:614-8. 7. Denko N, Krauel LH. Benign chondroblastoma of bone: an unusual localization in temporal bone. Arch PathoI1955;59: 710-1.
769
12. Tanohata K, Noda M, Katoh H, et al. Chondroblastoma of temporal bone. Neuroradiology 1986;28:367-70. 13. Vanderberg HJ lt, Coley BL. Primary tumors of the cranial bones. Surg Gynecol Obstet 1950;90:602-12.
8. Feely M, Keohane C. Chondroblastoma of the skull. J Neurol Neurosurg Psychiatry 1984;47:1348-50.
14. Steiner CG. Postradiation sarcoma of bone. Cancer 1965; 18:603-12.
9. Horn KL, Hankinson H, Nagel B, Erasmus M. Surgical management of chondroblastoma of the temporal bone. Otolaryngol Head Neck Surg 1990;102:264-9.
15. Kahn LB, Wood FM, Ackerman LV. Malignant chondroblastoma. Arch PathoI1969;88:371-6.
10. Peipgras U, Hirth R, Stadtler F, Kammerer V. Chondroblastoma of the temporal bone, an unusual cause of increasing intracranial pressure. Neuroradiology 1972;4:25-9.
16. Kyriakos M, Land VJ, Penning HL, Parker SG. Metastatic chondroblastoma. Report of a fatal case with a review of the literature on atypical, aggressive and malignant chondroblastorna. Cancer 1985;55:1770-89.
11. Spjut HJ, Dorfman RD, Fechner RE, Ackerman LV. Tumors of bone and cartilage. In: Firminger HI, ed. Atlas of tumor pathology. Washington, DC: Armed Forces Institute of Pathology, 1971:33-116.
17. Coltrera MD, Googe PB, Harrist TJ, Hyams VJ, Schiller AL, Goodman ML. Chondrosarcoma of the temporal bone. Diagnosis and treatment of 13 cases and review of the literature. Cancer 1986;58:2689-96.
AMERICAN AUDITORY SOCIETY, INC The 19th annual meeting of the American Auditory Society, Inc, will be held November 19, 1992, in San Antonio, Texas. For further information, contact Don W. Worthington, PhD, Chair, AAS Program Committee, Boys Town National Institute, 555 North 30th Street, Omaha, NE 68131.
28TH POSTGRADUATE COURSE IN EAR SURGERY The 28th Postgraduate Course in Ear Surgery will be held April 18-23, 1993, in Nijmegen, the Netherlands. For further information and registration form, please write to ProfDr P. van den Brock, University Hospital Nijmegen, Department ofOtorhinolaryngology, PO Box 9101, 6500 HB Nijmegen, the Netherlands; Fax: 080-540251.
CHONDROBLASTOMA OF THE TEMPORAL BONE CASE REPORT AND LITERATURE REVIEW MARK A. VARV ARES, MD MACK L. CHENEY, MD EMILY CEISLER, MD
MAx L. GooDMAN, MD
WILLIAM W. MONTGOMERY, MD BOSTON. MAsSACHUSETTS
Chondroblastoma is a rare tumor of bone that represents approximately 1% of all primary bone tumors. In the temporal bone. only 33 have been reported. We present a case of chondroblastoma of the temporal bone. followed by a literature review and analysis of reported cases. We conclude that the best chance for a prolonged disease-free interval is total excision using a combined otolaryngologic and neurosurgical approach. KEY WORDS -
chondroblastoma, connective tissue neoplasms. temporal bone. INTRODUcnON
oral analgesics. Eventually, a computed tomography (Cf) scan was done that showed a large lesion of the right petrous bone with extension into the middle cranial and infratemporal fossae (Fig I). The lesion in the right external auditory canal was again submitted to biopsy, this time with a diagnosis of chondroblastoma. He was then referred to the senior author (W.W.M.)
Benign chondroblastoma is a rare tumor of bone that represents approximately I % ofall primary bone tumors. These tumors are most commonly found arising in the epiphysis ofa long bone, with the femur, humerus, and tibia being the most commonly affected.! Primary bone tumors of the cranial bones are considered rare, comprising 2% of all primary bone tumors.s A chondroblastoma of the temporal bone is an even rarer entity, with only 32 cases having been reported previously.lU
At presentation, the patient complained of severe right-sided otalgia. Physical examination revealed a tender swelling over the right temporal and preauricular area. The right external auditory canal was occluded by a tumor. The patient's Weber examination lateralized to the left. The remainder of the findings on neurotologic examination, including cranial nerves, were unremarkable. Examination of the oral cavity showed painful trismus. The remainder of his head and neck examination was without evidence of any other masses. An audiogram was obtained that was essentially normal.
We now present a case of chondroblastoma of the temporal bone that was referred for definitive treatment. Included is a comprehensive review ofall cases reported to date, including symptoms, physical examination findings, radiographic data, treatment modalities, and outcome. CASE REPORT
A 33-year-old man presented with a l-year history of right-sided otalgia. Subsequently. he developed decreased hearing on the right with progressive dysequilibrium and headache. A slowly enlarging mass was noted in his right temporal area.
A magnetic resonance imaging (MRI) scan was performed and showed a large extradural lesion ofthe right petrous bone, with extension into the middle and infratemporal fossae. A preoperative cerebral arteriogram was consistent with an avascular mass without carotid compression or displacement.
Initial evaluation at an outside institution revealed a mass in his right external auditory canal. A biopsy yielded diagnosis ofgranulation tissue. He was treated with enteral antibiotics, but noted no improvement in his symptoms. He then underwent treatment for presumed temporomandibular joint dysfunction with
Upon consideration of the tumor location, a combined one-stage procedure with neurosurgery was planned. In the operating room the patient was prepared for an intracranial-extradural, transcervicaltransmastoid surgical approach with an extended parotidectomy incision that extended superiorly well
From the Department of Otolaryngology. Massachusetts Eye and Ear Infirmary. Harvard Medical School, Boston, Massachusetts. REPRINTS - William W. Montgomery, MD, Dept of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles 51,Boston, MA 02114.
763
764
Varvares et al, Temporal Bone Chondroblastoma
Fig 1. Contrast-enhanced computed tomograms of right temporal bone showing extent of bone destruction and encroachment of lesion on middle cranial fossa. A) Axial. B) Coronal.
into the temporal fossa and inferiorly into the neck along the anterior border of the sternocleidomastoid muscle (Fig 2A). As an initial maneuver, the common carotid artery and internal jugular vein were isolated so as to obtain proximal vascular control. An anterior skin flap was elevated over the parotid and the external auditory canal was transected and oversewn. The facial nerve was isolated at the stylomastoid foramen. A superficial parotidectomy was performed and the entire extratemporal facial nerve was identified and preserved. The lateral extent of the tumor was identified deep to the facial nerve. The mastoid cortex was exposed and a wide field mastoidectomy was performed. This exposure allowed the intratemporal portion of the tumor to be identified. The facial nerve was dissected as far as the geniculate ganglion. A middle fossa craniotomy was required to visualize the intracranial tumor. The medial resection margins and the labyrinthine portion of the facial nerve were fully visualized. During the extradural dissection, it was noted that the tumor was adherent to the dura but was able to be dissected free. As a final step in the resection, the zygomatic arch was transected. The condyle of the mandible and the infratemporal fossa contents were freed and the tumor was able to be delivered essentially en bloc. After hemostasis was obtained, a 6 x 6-cm tissue defect remained. This area included open air cells of the temporal bone, the internal auditory canal and associated nerves, and the trigeminal nerve (Fig 2B). A large fat graft harvested from the abdomen was used to obliterate the defect (Fig 2C). The wound was then closed in layers and drained. At the conclusion of the operation and just prior to wound closure, stimulation of the seventh cranial nerve at the internal auditory canal showed it
to be intact. Postoperatively, the patient recovered well. There was no evidence of cerebrospinal fluid leak, and the preoperative pain was relieved. The patient developed a temporary facial paresis that improved. An MRI scan with gadolinium and CT performed 2 years postoperatively revealed no evidence of recurrent or residual disease (Fig 3). Pathology examinations of the resected tissue showed a chondroblastoma tumor involving the temporomandibular joint, petrous temporal bone, and bony ear canal with nodular extensions into soft tissues. Histologically, the cellular features were characteristic of chondroblastoma neoplasms (Fig 4). LITERATURE REVIEW
Thirty-two cases of chondroblastoma of the bony ear canal with extensions into temporal bone have been reported, and 29 had detailed data. 1- lO,12,13 The 29 patients with detailed data and our patient are represented in the discussions.
Age and Sex Distribution. The ages of patients reported ranged from 2.9 years to 70 years of age. If the patient that was 2.9 years of age is excluded, the median age within the group was 43.8 years. The sex incidence was 21 males and 9 females for a male to female ratio of 2.3: 1. The age range for the males was 16 to 66 years, and for the females it was 2.9 to 70 years.
Presenting Symptoms. Twenty-six patients had a detailed description of presenting symptoms. The
Varvares et al, Temporal Bone Chondroblastoma
765
Fig 2. Surgical procedure. A) Outline of incision. B) Surgical defect. 1- sigmoid sinus. 2 - parotid gland. 3 - middle fossa dura. C) Obliterated surgical defect with adipose graft.
766
Varvares et al, Temporal Bone Chondroblastoma
766
TABLE 1. PRESENTING SYMPTOMS
Symptoms Hearing loss Otalgia Tinnitus Mass Vertigo or dysequilibrium Aural fullness or blocked ear Headache Seizures Pain Temporomandibular joint arthralgia or dysfunction Coma Facial numbness
Fig 3. Axial computed tomogram showing obliterated surgical defect and no evidence of recurrent disease.
most frequent presenting symptoms are listed in Table 1. Symptoms that were most prominent were hearing loss, otalgia, tinnitus, and a mass sensation in the ear. Most patients averaged two of the listed presenting symptoms, with a range of one to five. The average duration of symptoms prior to seeking medical attention was 12.5 months, although one patient reportedly had symptoms for 30 years; the range was from 2 months to 30 years.
No. of Pts 13 8 6 5 5 4 4 2 1
Physical Findings. Fourteen of the 29 patients had documented physical findings. The physical findings, in order of decreasing frequency, and the number of patients with each finding are listed in Table 2. The predominant alteration was a mass in the external auditory canal. Radiographic Data. Radiographic examinations reflected equipment available at the time ofpresentation. These include plain films, tomograms, CT, and MRI. Eight patients had plain films performed. The temporal bone lesions were described as osteolytic (two patients), destructive (two), cystic (two), erosive (one), and multichambered with marginal sclerosis (one). Five patients had tomograms, with the lesions described as normal (one), destructive (three), and erosive (one). Eight patients had CT performed. The lesions were described as soft tissue with spotty central calcifications (one), normal (one), soft tissue
Fig 4. Photomicrograph of resected tissue.
Varvares et al, Temporal Bone Chondroblastoma
TABLE 2. EXAMINATION FINDINGS Findings
Mass in external auditory canal Nontender temporal mass Tender temporal mass Papilledema Altered mental status Tenderness Trismus Nystagmus
TABLE 4. COMPLICATIONS IN FIVE PATIENTS
Patients (N
= 14)
No.
% 71
10 3 2 2
2 1 1 1
767
Complication
Type of Treatment Used
Conductive hearing loss Temporary cerebrospinal fluid leak, deafness, facial paralysis Temporary facial paralysis Radionecrosis of auricular cartilage requiring amputation Hearing loss
21 14 14 14 7 7 7
Total excision Total excision Total excision Radiotherapy (64 Gy) Total excision and radiotherapy (60 Gy)
DISCUSSION
mass with intracranial shift (two), lytic lesion (one), sharply demarcated solitary sclerotic lesion (one), destructive (one), and expansile (two). Two patients had MRI performed. Both of these lesions were reported as an expansile mass within the temporal bone.
Chondroblastoma, a rare tumor, represents less than 1% of primary bone tumorsl! and occurs predominantly in the epiphyseal area of long bones. They are more common in the second decade, with a male to female ratio of approximately 2:1.
Five patients had preoperative arteriograms. One showed a tumor blush, and the rest showed no evidence of a vascular mass.
The temporal bone chondroblastoma presents at an older age than other sites, with an average of 43.8 years. The male to female ratio is 2:1.
Treatment. The treatment modalities in the previously reported cases were total en bloc excision, curettage, irradiation, and irradiation combined with surgical excision. The most effective modality appears to be total excision with or without irradiation. The number of patients in each group, as well as the length of follow-up and the presence or absence of recurrence, is listed in Table 3.
The pathogenesis of chondroblastoma is uncertain. In long bones, it has been suggested that the chondroblastoma originates from the cells of the endochondral plate. Another theory proposes origin from reticulohistiocytes or related cells. Electron microscopic studies have concluded development from "normal cartilage cells to an altered local environment rather than an intrinsic alteration of cartilage cells per se."II(p33) Other electron microscopic studies have concluded origin from cartilage-forming matrix cells. I I
Complications of Treatment. Five patients had complications, and they are listed in Table 4, along with the initial type of treatment used. Hearing loss was the predominant complication. There have been reports of postirradiation sarcoma for treatments of other tumors and chondroblastomas in other sites, but this has not occurred in temporal bone chondroblastoma treatments. 14- 16 Metastatic chondroblastoma from the temporal bone has not been reported. 15,16
The endochondral origin for portions of the temporal bone and the potential for rests of cartilaginous cells may allow this lesion to develop, with the appropriate initiating event. Similar theories have been proposed for the development of chondrosarcoma, which may arise de novo in the temporal
TABLE 3. TREATMENT GROUPS
Treatment Total en bloc excision
Curettage or incomplete excision Radiotherapy (64 Gy) Curettage and postoperative radiotherapy (20 Gy) Total excision with preoperative (1 pt) or postoperative (2 pts) radiotherapy (60 Gy)
8
No.ofPts With Follow-up 7
13
10
0-9 y (average, 3.4 y)
9/lOt
1 1
1 1
3
3
8.5 Y 4.5 Y 0-9y (average, 7.5 y)
1/1 1/1 3/3§
No. of Pts
NED - with no evidence of disease. *One patient had curettage I month before total excision. tFour patients required two procedures because of recurrent or residual disease. §One patient had incomplete removal II months before complete excision.
Length of Follow-up
No.ofPts NED
0-63 mo (average, 21 mo)
7n*
768
Varvares et al, Temporal Bone Chondroblastoma
bone.l7 Temporal bone chondroblastoma malignancy has not been reported,15,16 secondary to irradiation or in the form of metastasis.14-16 The number of chondroblastoma patients receiving irradiation is small, and the potential for malignant transformation may not be adequately formulated. The primary presenting symptoms were predominantly otologic, with hearing loss being the most common. This was followed in decreasing frequency by otalgia, tinnitus, mass lesions, dysequilibrium, aural fullness, and headache, as well as other, less common complaints. These symptoms are all consistent with a slowly enlarging lesion of the temporal bone. The benign nature of this lesion is supported by the delay in presentation ofthe patients. Most patients had symptoms that had developed 1 year prior to seeking medical attention. The most common finding on physical examination was a mass, either in the external auditory canal or in the temporal area. A small percentage of patients presented with increased intracranial pressure as a result of their tumor, manifested as papilledema, altered mental status, or coma. The radiographic modalities used to evaluate these lesions were based primarily on the techniques available at the time of presentation. Earlier studies used primarily plain films and tomograms, whereas the later series used both CT and MR!. It is our opinion that CT allows clear delineation of the extent of bony destruction and MR! shows the tumor-dura interface and aids in determining if the tumor has remained extradural. Cerebral arteriography may be required for assessment of invasion or displacement of the internal carotid artery, or of tumor vascularity, and facilitates balloon test occlusion of the ipsilateral internal carotid artery should there be concern over possible sacrifice of this vessel. The reviewed cases of chondroblastoma of the temporal bone show that any of the modalities used thus far in the treatment may result in a prolonged disease-free interval. The data indicate that initial curettage of the lesion results in recurrences requiring secondary procedures before attaining a diseasefree interval. Patients who underwent an en bloc
resection or total excision of tumor had no evidence of recurrence at an average follow-up of 27 months. Irradiation used alone or in combination with curettage or total excision was equally effective in the small number of patients treated with it. It is evident that en bloc removal of tumor with the possibility of multiple cranial nerve deficits is not essential to obtaining a prolonged disease-free interval. Total excision of all gross tumor with careful preservation of the important neurovascular structures at the skull base should be adequate treatment for this benign lesion. This is attainable with the present surgical skills and approaches to skull base surgery. Radiotherapy is not recommended for this lesion. Our approach with this patient and to similar lesions of the temporal bone is as follows. After a complete history is taken, physical and neurotologic examinations are performed with radiographic and angiographic evaluations. Surgery is a combined procedure with neurosurgery. A transmastoid-transcervical approach by the otolaryngology team allows early control of the major vascular structures at the skull base, and the isolation of the tumor at the skull base with its intratemporal component. The neurosurgery team performs a temporal craniotomy using an extradural approach to obtain superior and medial margins and visualization of tumor and the critical structures in the middle fossa. This combined approach allows for relatively safe removal of all gross tumor while preserving the major neurovascular structures of the skull base. Adipose obliteration of the operative cavity with watertight closure helps to prevent postoperative cerebrospinal fluid leak. If the tumor cannot be removed from the dura with the dura remaining intact, this portion ofdura may be resected and reconstructed with fascia lata or irradiated homograft dura.? SUMMARY
A case ofchondroblastoma of the temporal bone is presented with a literature review of similar cases. The appropriate treatment appears to be a combined otolaryngologic-neurosurgical excision after proper clinical and radiographic evaluations to allow the total excision of the tumor with minimal morbidity.
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AMERICAN AUDITORY SOCIETY, INC The 19th annual meeting of the American Auditory Society, Inc, will be held November 19, 1992, in San Antonio, Texas. For further information, contact Don W. Worthington, PhD, Chair, AAS Program Committee, Boys Town National Institute, 555 North 30th Street, Omaha, NE 68131.
28TH POSTGRADUATE COURSE IN EAR SURGERY The 28th Postgraduate Course in Ear Surgery will be held April 18-23, 1993, in Nijmegen, the Netherlands. For further information and registration form, please write to ProfDr P. van den Brock, University Hospital Nijmegen, Department ofOtorhinolaryngology, PO Box 9101, 6500 HB Nijmegen, the Netherlands; Fax: 080-540251.
