Am J Otalaryngol 12:146-149.1991
Rhabdomyosarcoma of the Infratemporal Fossa: Diagnostic Dilemmas and Surgical Management JOSEPH E. DOHAR, MD, LAWRENCE J. MARENTETTE,
MD,
FACS,
AND GEORGE L. ADAMS,
MD,
FACS
We present a rare case of embryonal rhabdomyosarcoma in the infratemporal fossa presenting as an atypical facial pain syndrome. Radiographic imaging of the patient is discussed, and magnetic resonance imaging is recommended as the diagnostic modality of choice when mass lesions of the infratemporal fossa are suspected. Finally, a temporal approach to the infratemporal fossa is described, along with its advantages as an application for tumor resection in this anatomic region. AM J OTOLARYNGOL 12:146-149. Copyright 0 1991 by W.B. Saunders Company Key words: rhabdomyosarcoma, infratemporal fossa.
Rhabdomyosarcoma is the most common soft tissue sarcoma in children. Of the approximately 40% of rhabdomyosarcomas that occur in the head and neck region, the most common site is the orbit, followed by the nasopharynx and paranasal sinuses.l In contrast, the infratemporal fossa is an extremely rare site of presentation for such a tumor.’ Early diagnosis is critical since parameningeal sites of origin such as the infratemporal fossa are associated with a markedly decreased incidence of relapse-free survival at 3 years.’ The protean manner in which this tumor can manifest depending on its anatomic location makes early diagnosis quite challenging. The purpose of this article is threefold: (1) to bring to the attention of the practicing otolaryngologist-head and neck surgeon this extremely rare clinical presentation of rhabdomyosarcoma so that this diagnosis will be entertained, enabling earlier identification and management with, it is hoped, improved survival as a result; (2) to discuss the diagnostic options, with emphasis on high-resolution computer tomography (CT] scan-
ning versus magnetic resonance imaging (MRI) in this clinical setting; and, finally, (3) to describe a temporal approach that offers advantages for the surgical management of tumors in this anatomic region.
REPORT OF A CASE A previously healthy g-year-old boy presented with a l-month history of generalized left facial pain with associated left-sided otalgia. Additionally, on the day prior to presentation, the patient began to experience trismus. His past medical history was noncontributory except that he was taking Tegretol (Ciba-Geigy, Ardsley, NY) on a trial basis at the time of presentation to determine if his symptomatology was secondary to trigeminal neuralgia. He was referred to our institution because of the failure of the facial pain to resolve and because of the onset of trismus. Physical examination was completely normal except for an interincisal opening of only 3 mm. Laboratory evaluations, including a complete blood cell count with differential and platelets, coagulation profile, electrolytes, herpes simplex virus viral serology, and cerebrospinal fluid cell count with analysis for immunoglobulins, protein immunofixation, myelin basic protein, and oligoclonal bands, were all within normal limits. High-resolution, contrast-enhanced CT scanning was also within normal limits. Magnetic resonance imaging, however, revealed an irregular mass contained entirely within the infratemporal fossa showing no evidence of obvious invasion of the surrounding soft tissues and no bony erosion [Fig 1). The patient was admitted for surgical resection of this mass. A bicoronal incision was made from tragus to tragus and was deepened through the subcutaneous tissues (Fig 2). The galea aponeurotica was incised and
Received December 3, 1990, from the Department of Otolaryngology-Head and Neck Surgery, University of Minnesota Hospital and Clinic, Minneapolis, MN. Accepted for publication March 2, 1991. Address correspondence and reprint requests to George L. Adams, MD, FACS, Department of Otolaryngology-Head and Neck Surgery, Box 396, University of Minnesota Hospital and Clinic, Harvard Street at East River Rd. Minneapolis, MN 55455.
Copyright 0 1991 by W.B. Saunders Company 0196-0709/91/1203-0001$5.00/0
146
147
DOHAR ET AL
I. Magnetic resonance imaging demonstrates a moderately high signal intensity mass of the left infratemporal fossa on a Tl-weighted image with a homogeneous internal architecture.
Figure
sharp dissection was carried out in the subgaleal plane reflecting the frontal scalp anteriorly in the area of the temporalis muscle above the zygomatic arch. Next, the medial aspect of the zygomatic arch was identified and
the periosteum was incised. Subperiosteal dissection was then carried out anteriorly to the supraorbital rim and malar eminence. The arch of the zygoma was cut with a chisel and retracted inferiorly. Further dissection was carried out to the coronoid process, which was separated from the deep fibers of the masseter muscle, separated from the mandible by an osteotomy through its neck, and reflected superiorly along with its attached temporalis tendon. The internal maxillary artery was identified and ligated (Fig 3). The lateral pterygoid muscle was divided and medial to the muscle was a soft, yellow, indistinct and extremely friable tumor mass that was resected in pieces (Fig 4). The arch of the zygoma was then returned to its anatomic position and secured in place with titanium miniplates. The temporalis muscle was reapproximated with #3-o chromic suture in a simple interrupted fashion, and a standard three-layered closure of the scalp was achieved using #3-O PDS suture in the galeal and subcutaneous layer and staples in the skin. Results of microscopic examination were consistent with parameningeal embryonal rhabdomyosarcoma (Fig 5). Postoperatively, on adequate healing of the surgical site, the patient underwent 6 weeks of extended field radiation therapy to the infratemporal fossa. This was followed by 8 weeks of intrathecal methotrexate, hydrocortisone, and cytosine arabinoside along with highdose systemic cytoxan with Mesna (Asta Pharma Degussa, Frankfurt, Germany), vincristine, and actinomytin D administered according to a modification of the Intergroup Rhabdomyosarcoma Study (IRS] protocol.” The patient is currently completing his course of che-
Figure 3. Figure 2. Illustration depicting a bicoronal incision with extension into the preauricular crease on the patient’s left side.
The coronoid process is separated from the mandi-
ble and reflected cranially, pedicled to the temporalis muscle. The maxillary artery is seen coursing lateral to the lateral pterygoid muscle.
148
INFRATEMPORAL FOSSA RHABDOMYOSARCOMA
Figure 4. Exposure of the tumor mass lying intact within the left infratemporal fossa after separating the lateral pterygoid from its condylar attachment and reflecting it anteriorly.
motherapy and continues to complain which is being managed conservatively.
of trismus,
DISCUSSION Because the occurrence of rhabdomyosarcomas or any other mass lesions in the infratemporal fossa in children is extremely rare, these diagnoses are often not entertained when children present with a chief complaint of facial pain. Yet, because branches of the trigeminal nerve pass through the infratemporal fossa, pathologic processes occurring in this anatomic region may manifest as facial pain alone and must be included in the differential diagnosis. Clinical suspicion of a tumor in the infratemporal fossa is ordinarily confirmed by diagnostic imaging of this region. To date, the standard modality used to image this anatomic area has been high-resolution CT scanning.4 The case described, however, provides an instance when CT scanning failed to detect a mass in the infratemporal fossa that MRI delineated nicely. In fact, after the mass was identified on MRI, the CT scan was reviewed, revealing only a slight asymmetry of the pterygoid
musculature, which was felt to be within normal range. On the question of which imaging modality should be used when a mass lesion of the infratemporal fossa is suspected, Levine et al presented a series of representative cases in which malignant tumors involving the infratemporal fossa were better defined by axial MRI than by CT imaging.5 Barloon et al concluded that tumors involving the infratemporal fossa may be difficult to evaluate by CT due to severe interference from bone artifact and limited section planes6 These investigators stated that the advantages of MRI in this region include its multiplanar ability, its exquisite anatomic detail depiction, and especially its lack of bone artifacts from the bony confines of the infratemporal and retromaxillary fossae as well as the superior and inferior orbital fissures6 Two additional advantages of MRI over CT have been described by Som et al, who were able to differentiate tumors histologically to some degree on the basis of their appearance on MRI without the need for contrast.7.8 Som et al’s series of 40 cases included one rhabdomyosarcoma of the parapharyngeal space that had an intermediateintensity signal on Tl- and proton densityweighted images, with only a moderately highintensity signal on TZ-weighted images and a quite homogeneous internal architecture. These investigators concluded that this homogeneous appearance distinguishes the tumor from hypervascular tumors such as hemangiomas or paragangliomas. They could not, however, differentiate soft tissue sarcomas from neuromas, neurofibromas, or lymphomas with confidence on the basis of their appearance on MRI alone7; this was a similar limitation to that previously noted with CT.7 Finally, a recent review of head and neck MRI in the pediatric patient concluded that MRI combines the advantages of flexible imaging planes provided by ultrasound and CT without the need to subject patients to ionizing radiation, a particularly desirable advantage in the pediatric population.g Although CT has been advanced as a better modality for the evaluation of bony erosions or fractures, MRI can also demonstrate these lesions indirectly.g For these reasons, MRI appears to be the superior diagnostic imaging modality for mass lesions of the infratemporal fossa. When a diagnosis of rhabdomyosarcoma is ultimately confirmed by biopsy, multidisciplinary treatment is recommended, including surgical debulking and staging of the tumor, full-course extended field radiation therapy, and combination chemotherapy. lo We recommend a temporal approach to the infratemporal fossa for the biopsy, surgical staging, and debulking of these tumors on the basis of three distinct advantages: first, access
DOHAR
ET AL
Figure 5. Embryonal rhabdomyosarcoma. Note the diffuse sheets of small round and spindled cells that entrap skeletal muscle and fibrous tissue, and the presence of occasional cells resembling rhabdomyoblasts containing abundant eosinophilic cytoplasm.
and excellent exposure to the infratemporal fossa is afforded by this approach; second, no visible scar is left in the face; and, finally, the condyle is preserved, thereby maintaining the integrity of the temporomandibular joint and mandibular function.” We conclude that tumors of the infratemporal fossa, and rhabdomyosarcoma in particular, must be suspected in children who present with any persistent facial pain syndrome. Magnetic resonance imaging appears to be the superior diagnostic modality for mass lesions in this region, especially in the pediatric population. Finally, we recommend a temporal approach for surgical access to the infratemporal fossa.
4. McGill T: Rhabdomyosarcoma of the head and neck: update. Otolaryngol Clin North Am 1989; 22:631-636 5. Levine PA, Paling resolution CT scanning: Otolaryngol Head Neck
An
MR, Black WC, et al: MRI vs. highEvaluation of the anterior skull base. Surg 1987; 96:260-267
6. Barloon TJ, Yuh WTC, DeMarino DP, et al: Infratemporal fossa meningioma: CT and MR findings. J Comput Assist Tomogr 1987; 11:1050-1053 7. Som PM, Braun IF, Shapiro MD, et al: Tumors of the parapharyngeal space and upper neck: MR imaging characteristics. Radiology 1987; 164:823-829 8. Som PM. Sacher of the parapharyngeal ology 1988; 169:81-85
M, Stollman AL, et al: Common tumors space: Refined imaging diagnosis. Radi-
9. Dietrich RB, Lufkin RB, Kangarloo H. et al: Head and neck MR imaging in the pediatric patient. Radiology 1986; 159:769776
References 1. Feldman BA: Rhabdomyosarcoma Laryngoscope 1982; 92:424-440 2. Sutow W: Three-year relapse-free hood rhabdomyosarcoma of the head 492217-2221
3. Raney BR, Tefft M, Newton WA, et al: Improved prognosis with intensive treatment of children with cranial soft tissue sarcomas arising in nonorbital parameningeal sites. Cancer 1987; 59:147-155
of the head
and neck.
survival rates in childand neck. Cancer 1982;
10. Wharam MD, Beltangady MS, Heyn RM. et al: Pediatric orofacial laryngopharyngeal rhabdomyosarcoma-An Intergroup Rhabdomyosarcoma Study report. Arch Otolaryngol Head Neck Surg 1987; 113:1225-1227 11. Obwegesser HL: Temporal bit, and the retromaxillary-infracranial 1985; 7:185-199
approach to the TMJ. the orregion. Head Neck Surg
Rhabdomyosarcoma of the Infratemporal Fossa: Diagnostic Dilemmas and Surgical Management JOSEPH E. DOHAR, MD, LAWRENCE J. MARENTETTE,
MD,
FACS,
AND GEORGE L. ADAMS,
MD,
FACS
We present a rare case of embryonal rhabdomyosarcoma in the infratemporal fossa presenting as an atypical facial pain syndrome. Radiographic imaging of the patient is discussed, and magnetic resonance imaging is recommended as the diagnostic modality of choice when mass lesions of the infratemporal fossa are suspected. Finally, a temporal approach to the infratemporal fossa is described, along with its advantages as an application for tumor resection in this anatomic region. AM J OTOLARYNGOL 12:146-149. Copyright 0 1991 by W.B. Saunders Company Key words: rhabdomyosarcoma, infratemporal fossa.
Rhabdomyosarcoma is the most common soft tissue sarcoma in children. Of the approximately 40% of rhabdomyosarcomas that occur in the head and neck region, the most common site is the orbit, followed by the nasopharynx and paranasal sinuses.l In contrast, the infratemporal fossa is an extremely rare site of presentation for such a tumor.’ Early diagnosis is critical since parameningeal sites of origin such as the infratemporal fossa are associated with a markedly decreased incidence of relapse-free survival at 3 years.’ The protean manner in which this tumor can manifest depending on its anatomic location makes early diagnosis quite challenging. The purpose of this article is threefold: (1) to bring to the attention of the practicing otolaryngologist-head and neck surgeon this extremely rare clinical presentation of rhabdomyosarcoma so that this diagnosis will be entertained, enabling earlier identification and management with, it is hoped, improved survival as a result; (2) to discuss the diagnostic options, with emphasis on high-resolution computer tomography (CT] scan-
ning versus magnetic resonance imaging (MRI) in this clinical setting; and, finally, (3) to describe a temporal approach that offers advantages for the surgical management of tumors in this anatomic region.
REPORT OF A CASE A previously healthy g-year-old boy presented with a l-month history of generalized left facial pain with associated left-sided otalgia. Additionally, on the day prior to presentation, the patient began to experience trismus. His past medical history was noncontributory except that he was taking Tegretol (Ciba-Geigy, Ardsley, NY) on a trial basis at the time of presentation to determine if his symptomatology was secondary to trigeminal neuralgia. He was referred to our institution because of the failure of the facial pain to resolve and because of the onset of trismus. Physical examination was completely normal except for an interincisal opening of only 3 mm. Laboratory evaluations, including a complete blood cell count with differential and platelets, coagulation profile, electrolytes, herpes simplex virus viral serology, and cerebrospinal fluid cell count with analysis for immunoglobulins, protein immunofixation, myelin basic protein, and oligoclonal bands, were all within normal limits. High-resolution, contrast-enhanced CT scanning was also within normal limits. Magnetic resonance imaging, however, revealed an irregular mass contained entirely within the infratemporal fossa showing no evidence of obvious invasion of the surrounding soft tissues and no bony erosion [Fig 1). The patient was admitted for surgical resection of this mass. A bicoronal incision was made from tragus to tragus and was deepened through the subcutaneous tissues (Fig 2). The galea aponeurotica was incised and
Received December 3, 1990, from the Department of Otolaryngology-Head and Neck Surgery, University of Minnesota Hospital and Clinic, Minneapolis, MN. Accepted for publication March 2, 1991. Address correspondence and reprint requests to George L. Adams, MD, FACS, Department of Otolaryngology-Head and Neck Surgery, Box 396, University of Minnesota Hospital and Clinic, Harvard Street at East River Rd. Minneapolis, MN 55455.
Copyright 0 1991 by W.B. Saunders Company 0196-0709/91/1203-0001$5.00/0
146
147
DOHAR ET AL
I. Magnetic resonance imaging demonstrates a moderately high signal intensity mass of the left infratemporal fossa on a Tl-weighted image with a homogeneous internal architecture.
Figure
sharp dissection was carried out in the subgaleal plane reflecting the frontal scalp anteriorly in the area of the temporalis muscle above the zygomatic arch. Next, the medial aspect of the zygomatic arch was identified and
the periosteum was incised. Subperiosteal dissection was then carried out anteriorly to the supraorbital rim and malar eminence. The arch of the zygoma was cut with a chisel and retracted inferiorly. Further dissection was carried out to the coronoid process, which was separated from the deep fibers of the masseter muscle, separated from the mandible by an osteotomy through its neck, and reflected superiorly along with its attached temporalis tendon. The internal maxillary artery was identified and ligated (Fig 3). The lateral pterygoid muscle was divided and medial to the muscle was a soft, yellow, indistinct and extremely friable tumor mass that was resected in pieces (Fig 4). The arch of the zygoma was then returned to its anatomic position and secured in place with titanium miniplates. The temporalis muscle was reapproximated with #3-o chromic suture in a simple interrupted fashion, and a standard three-layered closure of the scalp was achieved using #3-O PDS suture in the galeal and subcutaneous layer and staples in the skin. Results of microscopic examination were consistent with parameningeal embryonal rhabdomyosarcoma (Fig 5). Postoperatively, on adequate healing of the surgical site, the patient underwent 6 weeks of extended field radiation therapy to the infratemporal fossa. This was followed by 8 weeks of intrathecal methotrexate, hydrocortisone, and cytosine arabinoside along with highdose systemic cytoxan with Mesna (Asta Pharma Degussa, Frankfurt, Germany), vincristine, and actinomytin D administered according to a modification of the Intergroup Rhabdomyosarcoma Study (IRS] protocol.” The patient is currently completing his course of che-
Figure 3. Figure 2. Illustration depicting a bicoronal incision with extension into the preauricular crease on the patient’s left side.
The coronoid process is separated from the mandi-
ble and reflected cranially, pedicled to the temporalis muscle. The maxillary artery is seen coursing lateral to the lateral pterygoid muscle.
148
INFRATEMPORAL FOSSA RHABDOMYOSARCOMA
Figure 4. Exposure of the tumor mass lying intact within the left infratemporal fossa after separating the lateral pterygoid from its condylar attachment and reflecting it anteriorly.
motherapy and continues to complain which is being managed conservatively.
of trismus,
DISCUSSION Because the occurrence of rhabdomyosarcomas or any other mass lesions in the infratemporal fossa in children is extremely rare, these diagnoses are often not entertained when children present with a chief complaint of facial pain. Yet, because branches of the trigeminal nerve pass through the infratemporal fossa, pathologic processes occurring in this anatomic region may manifest as facial pain alone and must be included in the differential diagnosis. Clinical suspicion of a tumor in the infratemporal fossa is ordinarily confirmed by diagnostic imaging of this region. To date, the standard modality used to image this anatomic area has been high-resolution CT scanning.4 The case described, however, provides an instance when CT scanning failed to detect a mass in the infratemporal fossa that MRI delineated nicely. In fact, after the mass was identified on MRI, the CT scan was reviewed, revealing only a slight asymmetry of the pterygoid
musculature, which was felt to be within normal range. On the question of which imaging modality should be used when a mass lesion of the infratemporal fossa is suspected, Levine et al presented a series of representative cases in which malignant tumors involving the infratemporal fossa were better defined by axial MRI than by CT imaging.5 Barloon et al concluded that tumors involving the infratemporal fossa may be difficult to evaluate by CT due to severe interference from bone artifact and limited section planes6 These investigators stated that the advantages of MRI in this region include its multiplanar ability, its exquisite anatomic detail depiction, and especially its lack of bone artifacts from the bony confines of the infratemporal and retromaxillary fossae as well as the superior and inferior orbital fissures6 Two additional advantages of MRI over CT have been described by Som et al, who were able to differentiate tumors histologically to some degree on the basis of their appearance on MRI without the need for contrast.7.8 Som et al’s series of 40 cases included one rhabdomyosarcoma of the parapharyngeal space that had an intermediateintensity signal on Tl- and proton densityweighted images, with only a moderately highintensity signal on TZ-weighted images and a quite homogeneous internal architecture. These investigators concluded that this homogeneous appearance distinguishes the tumor from hypervascular tumors such as hemangiomas or paragangliomas. They could not, however, differentiate soft tissue sarcomas from neuromas, neurofibromas, or lymphomas with confidence on the basis of their appearance on MRI alone7; this was a similar limitation to that previously noted with CT.7 Finally, a recent review of head and neck MRI in the pediatric patient concluded that MRI combines the advantages of flexible imaging planes provided by ultrasound and CT without the need to subject patients to ionizing radiation, a particularly desirable advantage in the pediatric population.g Although CT has been advanced as a better modality for the evaluation of bony erosions or fractures, MRI can also demonstrate these lesions indirectly.g For these reasons, MRI appears to be the superior diagnostic imaging modality for mass lesions of the infratemporal fossa. When a diagnosis of rhabdomyosarcoma is ultimately confirmed by biopsy, multidisciplinary treatment is recommended, including surgical debulking and staging of the tumor, full-course extended field radiation therapy, and combination chemotherapy. lo We recommend a temporal approach to the infratemporal fossa for the biopsy, surgical staging, and debulking of these tumors on the basis of three distinct advantages: first, access
DOHAR
ET AL
Figure 5. Embryonal rhabdomyosarcoma. Note the diffuse sheets of small round and spindled cells that entrap skeletal muscle and fibrous tissue, and the presence of occasional cells resembling rhabdomyoblasts containing abundant eosinophilic cytoplasm.
and excellent exposure to the infratemporal fossa is afforded by this approach; second, no visible scar is left in the face; and, finally, the condyle is preserved, thereby maintaining the integrity of the temporomandibular joint and mandibular function.” We conclude that tumors of the infratemporal fossa, and rhabdomyosarcoma in particular, must be suspected in children who present with any persistent facial pain syndrome. Magnetic resonance imaging appears to be the superior diagnostic modality for mass lesions in this region, especially in the pediatric population. Finally, we recommend a temporal approach for surgical access to the infratemporal fossa.
4. McGill T: Rhabdomyosarcoma of the head and neck: update. Otolaryngol Clin North Am 1989; 22:631-636 5. Levine PA, Paling resolution CT scanning: Otolaryngol Head Neck
An
MR, Black WC, et al: MRI vs. highEvaluation of the anterior skull base. Surg 1987; 96:260-267
6. Barloon TJ, Yuh WTC, DeMarino DP, et al: Infratemporal fossa meningioma: CT and MR findings. J Comput Assist Tomogr 1987; 11:1050-1053 7. Som PM, Braun IF, Shapiro MD, et al: Tumors of the parapharyngeal space and upper neck: MR imaging characteristics. Radiology 1987; 164:823-829 8. Som PM. Sacher of the parapharyngeal ology 1988; 169:81-85
M, Stollman AL, et al: Common tumors space: Refined imaging diagnosis. Radi-
9. Dietrich RB, Lufkin RB, Kangarloo H. et al: Head and neck MR imaging in the pediatric patient. Radiology 1986; 159:769776
References 1. Feldman BA: Rhabdomyosarcoma Laryngoscope 1982; 92:424-440 2. Sutow W: Three-year relapse-free hood rhabdomyosarcoma of the head 492217-2221
3. Raney BR, Tefft M, Newton WA, et al: Improved prognosis with intensive treatment of children with cranial soft tissue sarcomas arising in nonorbital parameningeal sites. Cancer 1987; 59:147-155
of the head
and neck.
survival rates in childand neck. Cancer 1982;
10. Wharam MD, Beltangady MS, Heyn RM. et al: Pediatric orofacial laryngopharyngeal rhabdomyosarcoma-An Intergroup Rhabdomyosarcoma Study report. Arch Otolaryngol Head Neck Surg 1987; 113:1225-1227 11. Obwegesser HL: Temporal bit, and the retromaxillary-infracranial 1985; 7:185-199
approach to the TMJ. the orregion. Head Neck Surg
