Conditions that may present as a retrotympanic mass
High jugular bulb
Aberrant carotid artery
Tumors and tumor-like condition
Facial nerve tumor (neuroma, hemangioma)
Meningioma (primary or secondary to temporal bone invasion)
Chordoma, chondrosarcoma of the jugular foramen (with temporal bone invasion)
This condition is depicted in the following figures ( ▶ Fig. 12.1, ▶ Fig. 12.2, ▶ Fig. 12.3, ▶ Fig. 12.4, ▶ Fig. 12.5, ▶ Fig. 12.6, ▶ Fig. 12.7, ▶ Fig. 12.8, ▶ Fig. 12.9, ▶ Fig. 12.10, ▶ Fig. 12.11, ▶ Fig. 12.12, ▶ Fig. 12.13, ▶ Fig. 12.14, ▶ Fig. 12.15, ▶ Fig. 12.16, ▶ Fig. 12.17, ▶ Fig. 12.18, ▶ Fig. 12.19).
Fig. 12.1 Left ear. This patient presented with dysphagia as her only symptom. A nonpulsating retrotympanic mass was noticed. The mass was whitish rather than the reddish color characteristic of glomus tumor. Computed tomography (CT) scan and magnetic resonance imaging (MRI) demonstrated an en-plaque meningioma invading the posterior surface of the temporal bone.
Fig. 12.2 MRI of the case presented in ▶ Fig. 11.2. Large posterior fossa meningioma located along the posterior surface of the petrous bone.
Fig. 12.3 Postoperative CT scan of the case described in ▶ Fig. 12.1. The tumor was removed using a modified transcochlear approach. The surgical cavity was obliterated using abdominal fat (F).
Fig. 12.4 Left ear. Pinkish nonpulsating retrotympanic mass. This 40-year-old patient referred to our clinic for persistent temporal and occipital headache, left hearing loss, and vertigo. Neuroradiological investigations revealed a huge tumor arising from the jugular foramen (see ▶ Fig. 12.5, ▶ Fig. 12.6, ▶ Fig. 12.7), which proved to be a meningioma. The disease was removed through a staged procedure (first stage: removal of the extradural and cervical portion; second stage: removal of the intradural portion).
Fig. 12.5 MRI of the same case, axial view (T1W + gadolinium enhancement). The lesion extends to the posterior fossa (cerebellum, red arrow; medulla oblongata, yellow arrow) and infratemporal fossa (green arrow).
Fig. 12.6 MRI of the same case, coronal view (T2W). Note the cervical extension of the lesion (arrow).
Fig. 12.7 CT scan of the same case, coronal view. Note the massive erosion and involvement of the temporal bone and jugular foramen area (yellow arrow). The left jugular tubercle has been completely eroded by the lesion (green arrow), which starts to infiltrate even the occipital condyle (red arrow). Intratumoral calcifications can be seen.
Fig. 12.8 Right ear. Case of an en-plaque meningioma in a 67-year-old patient. The otoscopy shows a reddish nonpulsating retrotympanic mass. Right ear fullness, intermittent pulsatile tinnitus, and dizziness are the only complaints. Considering patient’s age, symptoms, the high morbidity related to the surgical treatment, and the slow growing nature of the lesion, a wait-and-scan protocol was adopted. Since 2 years from the diagnosis, the lesion has not yet grown.
Fig. 12.9 MRI of the same case (T1W + gadolinium enhancement), axial view. The internal carotid artery is enchased by the tumor (yellow arrow), which shows broad dural attachment.
Fig. 12.10 MRI of the same case (T1W + gadolinium enhancement), axial view. The tumor extends in the internal auditory canal and cerebellopontine angle (yellow arrow).
Fig. 12.11 CT scan of the same case, axial view. The tumor extends into the middle ear cleft (arrow).
Fig. 12.12 Right ear. Petroclival meningioma. The otoscopy shows a pinkish nonpulsating retrotympanic mass in the anteroinferior quadrants. Eustachian tube is blocked by the tumor, resulting in middle ear effusion (note the opacification of the tympanic membrane).
Fig. 12.13 MRI of the same case, axial view (T1W + gadolinium enhancement), shows the extension of the tumor (T).
Fig. 12.14 Right huge meningioma extended to the posterior, infratemporal fossae, neck, and contralateral side. This 41-year-old patient refused surgical treatment and died 2 years after radiotherapy.
Fig. 12.15 MRI of the same case showing extension of the disease toward the contralateral side (arrow). Radical surgical removal of the tumor (T) is impossible due to the involvement of vital structures and the high risk of recurrence.
Fig. 12.16 MRI of the same case showing extension of the tumor in the infratemporal fossa. The internal carotid artery is displaced and completely engulfed by the disease (arrow).
Fig. 12.17 Another case of a skull base meningioma in a 42-year-old female patient presenting with a retrotympanic nonpulsating mass. The tumor, arising from the jugular foramen, was removed through a staged surgery for the presence of wide intradural portion. This avoids the risk of cerebrospinal fluid (CSF) leak in the neck after the first stage (in this case an infratemporal fossa approach type A).
Fig. 12.18 MRI, axial view, of the same case. Note the broad dural attachment of the tumor and its wide intradural portion (red arrow).
Fig. 12.19 Postoperative MRI (after 2 years from the second stage). The tumor has been completely removed and the cavity is obliterated with abdominal fat (arrow).
12.3 Lower Cranial Nerves Neurinoma
Fig. 12.20 Left ear. Lower cranial nerve neurinoma. Otoscopy shows a retrotympanic bulging. A pinkish mass is visible even in the hypotympanic area. This patient has been managed for 2 years with a wait-and-scan protocol. Due to a tumor growth and the onset of left IX and X cranial nerves palsy, we decided to remove the lesion through a transcochlear-transigmoid approach.
Fig. 12.21 CT scan, axial view, of the same case. The tumor involves the jugular foramen area, engulfing the vertical portion of the internal carotid artery (the yellow arrow shows the level of the free-contralateral artery) and eroding the clivus (red arrow).
Fig. 12.22 CT scan, axial view, of the same case. Even the medial wall of the horizontal portion of the internal carotid artery is in contact with the tumor (arrow).
Fig. 12.23 CT scan, coronal view, showing the extension of the tumor in the middle ear cleft (red arrow). The tumor spreads from the jugular foramen area eroding the inferior tympanic bone (yellow arrow).
Fig. 12.24 MRI scan of the same case, axial view (T2W). Note the dumbbell-shaped pattern of the tumor (T)
Fig. 12.25 Postoperative MRI of the same case. Total tumor removal has been accomplished. The cavity is obliterated with abdominal fat (F).
12.4 Chondrosarcoma of the Jugular Foramen
Fig. 12.26 Left ear. Bulging of the whole tympanic membrane for a retrotympanic nonpulsating mass. This 45-year-old female patient underwent transtympanic tube insertion elsewhere for the suspect of a glue ear. One month after tube placement, she developed left IX and X cranial nerves palsy. An MRI showed the presence of a jugular foramen lesion, which proved to be a chondrosarcoma. Chondrosarcomas of the skull are rare slow-growing locally aggressive malignant tumors. These tumors rarely metastasize; therefore, local control represents the goal of therapy. The ideal primary treatment of these tumors is total surgical removal. Radiotherapy may constitute a viable alternative to surgery in selected cases in which there are serious contraindications to surgery as well as in cases with partial excision or with high risk of recurrence. Proton beam radiotherapy, radiosurgery (Gamma knife or Cyber knife), or fractioned radiotherapy is often used as an adjuvant treatment.
Fig. 12.27 CT scan, coronal view, of the same case. The tumor spreads from the jugular foramen to the middle ear. Irregular bone erosion of the jugular foramen and the occipital condyle (arrow) can be observed.
Fig. 12.28 MRI scan, coronal view, of the same case (T2W). The tumor (T) appears as a lobulated destructive mass.
Fig. 12.29 Postoperative CT scan, axial view. Total tumor removal has been accomplished with an infratemporal fossa type A approach. The cavity is obliterated with abdominal fat. The patient underwent adjuvant proton beam radiotherapy.
Fig. 12.30 Postoperative MRI scan (3 years after surgery), axial view (T1W + gadolinium enhancement). No recurrence can be observed. The ipsilateral jugular bulb and the vertical portion of the internal carotid artery were closed by the tumor itself preoperatively (JB indicates the bulb on the contralateral side, the arrow indicates the contralateral vertical portion of the internal carotid artery).