|Year : 2022 | Volume
| Issue : 1 | Page : 88-90
Temporal bone rhabdomyosarcoma mimicking chronic suppurative otitis media
Isha Shah, Siddharth Malukar, Jayesh Singh, Ankita Parikh, U Suryanarayana Kunikullaya
Department of Radiation Oncology, The Gujarat Cancer and Research Institute, Ahmedabad, Gujarat, India
|Date of Submission||21-Oct-2021|
|Date of Acceptance||06-Jan-2022|
|Date of Web Publication||25-Apr-2022|
Dr. Isha Shah
Department of Radiation Oncology, The Gujarat Cancer and Research Institute, Ahmedabad - 380 016, Gujarat
Source of Support: None, Conflict of Interest: None
Rhabdomyosarcoma (RMS) is one of the most commonly encountered soft-tissue sarcomas in childhood. The most common location is in the head-and-neck region, followed by the urogenital system, extremities, and torso. Head and neck is a common site though the temporal bone is an extremely rare site with only a few reported cases in the literature till now. Herein, we report a case of a sclerosing type of temporal bone RMS in an 8-year-old young girl. We discuss clinical, pathological, radiological findings and management of temporal bone RMS. Misdiagnosis is common because of this aggressive temporal bone lesion's similarity to more common benign diseases. Clinicians should maintain suspicion for RMS in patients with chronic otitis media not responsive to medical therapy and should refer a specialist multidisciplinary team in a timely manner as an early diagnosis will optimize the chance of survival. Clinical features, radiologic findings, and histopathological examination using immunohistochemistry are all important for the correct diagnosis of temporal bone RMS. It is important to be aware of and to know how to deal with such rare cases.
Keywords: Chronic suppurative otitis media, otitis media, rhabdomyosarcoma, sclerosing
|How to cite this article:|
Shah I, Malukar S, Singh J, Parikh A, Kunikullaya U S. Temporal bone rhabdomyosarcoma mimicking chronic suppurative otitis media. Indian J Otol 2022;28:88-90
|How to cite this URL:|
Shah I, Malukar S, Singh J, Parikh A, Kunikullaya U S. Temporal bone rhabdomyosarcoma mimicking chronic suppurative otitis media. Indian J Otol [serial online] 2022 [cited 2022 Nov 29];28:88-90. Available from: https://www.indianjotol.org/text.asp?2022/28/1/88/343753
| Introduction|| |
Sarcoma is a cancer of soft tissue, connective tissue, muscle, tendon, cartilage, or bone. Rhabdomyosarcoma (RMS) is a type of sarcoma that usually begins in muscles that are attached to bones. RMS accounts for approximately 3.5% of the cases of cancer among children aged 0 to 14 years. The incidence of RMS is 4.5 cases per 1 million children, which translates into about 350 cases per year. It is a fast-growing and highly malignant soft-tissue tumor of the childhood with predilection for the head and neck, genitourinary system, and extremities. Pediatric RMSs are classified into embryonal RMS, alveolar RMS, botryoid, spindle cell/sclerosing, and pleomorphic subtypes. Among them, embryonal RMS is the most common and sclerosing RMS (SRMS) is accounting for <2% among all., SRMS is a recently described type of RMS, and it was first reported by Mentzel and Katenkamp in 2000. Head-and-neck region is the common site for occurrence of RMSs, but primary intracranial RMSs are rare, with an incidence of around 3%. SRMS of the temporal bone is very rare and is more aggressive than other subtypes. They are rarely considered in the differential diagnoses of intracranial tumors as they mimic complicated chronic suppurative otitis media (CSOM) and other ear canal masses that may delay the diagnosis of RMS. Diagnosis is best confirmed through histopathology. Radiological imaging is useful to determine the extent of disease. Multimodality treatment with surgery, radiotherapy, and chemotherapy is the best approach to treat such cases. We hereby present a case of left temporal bone SRMS in an 8-year-old young girl and will discuss the literature pertinent to pediatric SRMSs.
| Case Report|| |
An 8-year-old girl initially presented with headache and vomiting for 2 months. Headache was mild on the left frontal region and continuous throughout the day, not relieved by medication. She had 1–2 episodes of vomiting per day. It was gradually associated with increasing headache and swelling of the left eyeball, though no visual difficulties were noted before by the patient and her parents. Lately, the patient had mild left side earache and was associated with mild nonfoul-smelling discharge. Computed tomography (CT) of the brain was performed at an outside hospital which was in favor of a mass-like lesion in the left petrous part of the temporal bone. She was referred to our institute for further management.
On physical examination, the patient was conscious and well oriented with a good general condition. Her pupils were equal and reactive, visual acuity was grossly intact, conjunctivae and cornea were apparently normal bilaterally, and no nystagmus was noted. Examination of the face revealed no facial weakness, but there was an incomplete left eye closure. On the tuning fork test, there was a mild conductive hearing loss on the left side ear. No palpable lymphadenopathy in the neck was noted. Other cranial nerve examinations detected no abnormalities. No other abnormalities were detected, and bowel bladder habits were unaltered. Differential diagnoses included an infection such as cholesteatoma or otitis media, a benign tumor such as schwannoma or osteoma, and malignant tumors such as RMS, lymphoma, or squamous cell carcinoma.
Diagnostic assessment and therapeutic intervention
A CT scan of the brain showed a 35 mm × 23 mm × 28 mm lesion along the left petrous temporal bone and cavernous sinus. The lesion was projecting into the middle cranial fossa. Encasement and occlusion of the left internal carotid artery in the carotid canal and cavernous sinus were seen. Erosion of the left middle ear cavity in the anterosuperior wall was noted. CT scan findings were further confirmed by the magnetic resonance imaging (MRI) of the brain which showed a 25 mm × 31 mm × 36 mm well-defined dural-based altered intensity lesion involving the left infratemporal fossa and left petrous part of the temporal bone with underlying erosion as shown in T1-weighted image in [Figure 1]. Erosion of internal acoustic meatus, inner ear, carotid canal, and jugular foramen was present. The lesion also extended into the middle ear cavity. Differential diagnosis was meningioma, nerve sheath tumors such as schwannoma or glomus tumor.
|Figure 1: T1-weighted magnetic resonance image showing altered signal intensity lesion in the left infratemporal fossa involving the petrous part of the temporal bone|
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Temporal craniotomy and subtotal excision of lesion were performed. Histopathology report showed spindle-shaped, polygonal, or round cells embedded in an abundant dense hyalinizing extracellular matrix and pseudovascular growth pattern suggesting the possibility of high-grade primary malignant bone tumor or SRMS or rhabdoid tumor as shown in [Figure 2]. Further to confirm the diagnosis, immunohistochemistry of the tumor was done which was positive for MyoD1, desmin, and vimentin. It was patchy positive for SATB2 and focally positive for EMA. INI-1 was retained.
Postoperative MRI was suggestive of a 37 mm × 51 mm well-defined dural-based altered intensity residual lesion in the left infratemporal fossa involving the petrous part of the temporal bone with its underlying erosion, and postoperative edematous component was present. Thus, the patient was diagnosed as a Stage II, Group 3 sclerosing type of RMS of the temporal bone.
Further metastatic workup (including contrast-enhanced CT [CECT] chest and abdomen, bone scan, MRI whole spine screening, and cerebrospinal fluid cytology) was done which were negative. The patient was planned for a radical approach and received craniospinal irradiation and chemotherapy. Craniospinal irradiation was given with a three-dimensional conformal radiotherapy technique. Radiotherapy doses of 36Gy in 20 fractions at 1.8Gy per fraction, 5 fractions per week with standard protocol is delivered to the cranial and spinal field. Then dose is further boosted up to 54 Gy to primary lesion with adequate margin on a 6MV linear accelerator. Junction of the cranial and spinal field was kept at neck level to avoid the exit of the spinal field beam from the oral cavity, as a consequence creating hot and cold spots at a junction was managed by junction shift technique also known as feathering. After every seventh fraction, the junction shift was done in a longitudinal direction. The patient had received weekly concurrent vincristine chemotherapy with radiation and continued on adjuvant chemotherapy with vincristine, actinomycin D, and cyclophosphamide chemotherapy at a 3-week interval.
Follow-up and outcomes
On follow-up at 3 months, CECT brain suggested a significant reduction in the residual infratemporal tumor and further the patient was kept on chemotherapy.
| Discussion|| |
RMSs are the most common childhood soft-tissue tumors. It is seen in the head and neck, genitourinary system, and extremities. According to the International Classification of Childhood Sarcomas, pediatric RMSs have been classified into embryonal, alveolar, botryoid, and spindle cell/sclerosing subtypes.
Head-and-neck region is a common site for occurrence of RMSs, and primary intracranial RMSs are rarely seen. Very few cases were reported in petrosal locations from the onset. Clinical course and prognosis are very different for these tumors. Patients usually present with a persistent frontal headache. Abducens nerve paralysis occurs in such cases due to lesion causing compression on Dorello's canal. Other cranial nerve involvements such as facial, auditory, or vestibular nerves are rare. This enables predominantly petrous RMSs to typically spare the seventh cranial nerve. However, in our case, a petrous bone lesion started eroding the internal acoustic meatus and inner ear affecting the seventh and eighth cranial nerves, so the patient presented with mild hearing loss and incomplete closure of the eye.
The histopathological features of SRMSs show spindle-shaped, polygonal, or round cells embedded in an abundant hyalinizing extracellular matrix. Dense prominent acellular hyaline matrix and pseudovascular growth pattern lead to misdiagnosis as osteosarcoma, chondrosarcoma, or angiosarcoma. They are strongly positive for the MyoD1 immunohistochemistry marker and lack alveolar pattern. Hence, some authors have suggested these tumors to be either a variant of embryonal RMS or a new subtype of RMS and named these tumors as “SRMSs.” SRMS lacks the typical features of embryonal RMSs as well. Due to their some similarities with embryonal RMSs and some with alveolar RMSs, its manifestation as a separate subtype is uncertain.
More and more such cases of sclerosing subtype are known in the literature now. Longer follow-up studies are needed to know the aggressiveness and malignant potential of SRMSs. Since no definite treatment guidelines are given for SRMS, they should be treated with surgical resection, radiotherapy, and aggressive chemotherapy as like other sarcomas, but one should be aware that treatment failure rate for pediatric SRMS is high.
To summarize this, SRMS of the temporal bone is very rare and is more aggressive than other subtypes. They are rarely considered in the differential diagnoses of intracranial tumors as they mimic complicated CSOM and other ear canal masses that may delay the diagnosis of RMS. Diagnosis is best confirmed through histopathology. CT and MRI are useful to determine the extent of disease. Multimodality treatment with surgery, radiotherapy, and chemotherapy is the best approach to treat such cases.
| Conclusion|| |
It is important to remember that although RMS is commonly seen in children, SRMS is a recently described entity. Furthermore, the literature regarding the clinical behavior and outcome is very less. By being alert for less common differential diagnosis and following clinical features, radiologic findings, and histopathological examination, knowing when to refer to a specialist, clinicians can make timely diagnosis and help patients to receive prompt and appropriate multimodality treatment. It is important to be aware of and to know how to deal with such rare cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]