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Tc 99m m= meta-stable.


Glomus By Basim Metwally 30/03/2010


Nomenclature Glomus (Angio-neuro-myoma): Arises from the glomera which are AV shunts in the distal extremities.

Chemodectoma: Chromaffin positive.

Paraganglioma.


Tumors of Neural Crest


Nomenclature 

Paraganglioma:

Suprarenal:

Pheochromocytoma: Chromaffin +ve

Extra adrenal: if persistent after birth:

Head and Neck. Para-aortic. Walls of viscera of chest and abdomen. Retroperitoneal. Mediastinal.

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Paraganglioma 

Paraganglioma of Head and Neck:

Carotid body tumor (Glomus Caroticum): 35-50%. Glomus jugulare: 30%. Glomus tympanicum. 18% Glomus juxta-vagale: 11%. Laryngeal paraganglioma. Nasal and nasopharyngeal paraganglioma. Orbital Paraganglioma. Rare sites: Pterygo-palatine – buccal cavity.

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Historical Background 

Carotid body was first described by Von Haller in 1743.

Renamed vascular glomerulus or glomus in early 20th century.

Paraganglion first used by histologist Kohn while describing carotid body.

In 1941, Guild first described "glomic tissue" in the temporal bone.


Historical Background 

1945, Rosenwasser reported a “carotid body tumor” of middle ear and mastoid.

In 1978, by Fisch's classification system, and subsequently.

In 1981, by Glasscock and Jackson's proposed scheme.

The latter two are used currently.


Jugulo-tympanic Paraganglioma  

Microscopic Picture: Type I (Epitheloid cells - Chief cells) : are members of APUD family and arranged in clusters (Zellballen) with a highly vascular stroma. Type II (sustentacular cells - Neural elements ): the supporting cells which are commonly found in paraganglioma, but frequently absent in jugulo-tympanic paraganglioma. Nuclear polymorphism and cellular hyperchromatism common : not considered evidence of malignancy. Electron Microscopy: Membrane bound electron dense granules (responsible for catecholamines release).


Jugulo-tympanic Paraganglioma 

Incidence:

Commonest benign tumor of the middle ear. 2nd most common tumor of the temporal bone. Age: peak at 40 – 60 years. ♀ : ♂ is 5 : 1. Rules of 10: 10% familial , 10% multicentric, 10% secretory, 10% may turn into malignancy. Multicentricity increases by 30% if there is a family history.

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Jugulo-tympanic Paraganglioma 

Site:

Glomus Jugulare: (85%) paraganglia at the adventitia of the dome of the jugular bulb.

Glomus tympanicum: (12%) paraganglia on the promontory of cochlea in the middle ear.

Arnold’s nerve: gives rise to glomus tympanicum in (3%) of cases.


Jugulo-tympanic Paraganglioma 

Blood Supply:

Ascending Pharyngeal artery. Posterior division of middle meningeal artery. Stylomastoid branch of occipital artery. Posterior auricular artery. Anterior/posterior meningeal branches of vertebral artery. Anterior/posterior inferior cerebellar artery. Tiny branches of ICA.

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Jugulo-tympanic Paraganglioma 

Spread:

Slowly growing tumor. Inferiorly: jugular foramen, hypoglossal canal, infratemporal fossa. Superiorly: middle cranial fossa. Medially: inner ear and facial nerve. Laterally: EAC through the drum. Posteriorly: mastoid - lateral sinus - posterior cranial fossa. Distant: to cervical L.N. and lungs if malignant transformation occurs.

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Jugulo-tympanic Paraganglioma 

C/P:

Otological:

Tinnitus: Pulsatile – Early – heard with every heart beat. Hearing Loss: CHL – SNHL. Ear discharge. Otalgia and Vertigo: Rare. Reddish/bluish mass behind an intact drum: (Rising Sun). Brown’s sign. Aquino sign. Aural vascular polyp. Auscultation: Bruit.

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Jugulo-tympanic Paraganglioma 

C/P:

Cranial nerves manifestations:

Facial nerve. (the earliest and the most common). 9th , 10th and 11th Cranial Nerves: at jugular foramen. Hypoglossal nerve at hypoglossal canal. 5th and 6th Cranial Nerves: due to intracranial extension. 8th Cranial Nerve: due to erosion of the labyrinth.

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↑Intra-cranial tension manifestations.


Jugulo-tympanic Paraganglioma 

Associations:

Thyroid C-cell carcinoma. Parathyroid adenoma. Pheochromocytoma. The MEN syndromes.

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Jugulo-tympanic Paraganglioma  

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Differential Diagnosis: Red drum: aberrant ICA - high jugular bulb – hemotympanum- otosclerosis. Pulsatile tinnitus: A-V Malformation - high riding carotid artery - Carotid stenosis - Persistent stapedial artery Venous hums - Dehiscent jugular bulb - Transverse sinus obstruction – vascular loop. Neural lesions (neurolemmoma, neurofibroma). Chordoma and osteoblastoma. Adenoma and adenocarcinoma. Inflammatory polyps, cholesterol granuloma. Metastatic lesions (lung, breast, prostate).


Jugulo-tympanic Paraganglioma   

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Investigations: CT with contrast (fine cuts): The finding of air or bone between the tumor and the jugular bulb → diagnosis of a tympanicum. In early glomus jugulare: Chewing of air cells. Glomus jugulare: tend to erode the bony plate between the jugular bulb and the internal carotid artery. An intact petrous carotid canal is helpful in ruling out an aberrant carotid artery. MRI with contrast: Salt and Pepper appearance in T2W. Angiography and digital subtraction angiography: Tumor appears as a blush of dye.


Jugulo-tympanic Paraganglioma.        

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Investigations: PTA and Tympanogram: CHL or mixed HL. Oscillating tympanogram. Lab Studies: 24 hours VMA and catecholamines. Biopsy: From a polyp if present. If bleeding occurs, this can be stopped by BIPP. FNAC: Not advised. Abdominal CT: If symptomatic ( flushing, HTN etc).


Jugulo-tympanic Paraganglioma 

Classifications:

Glasscock-Jackson Classification:

Glomus Tympanicum: I. Small Mass limited to promontory. II. Tumor filling middle ear space. III. Tumor filling middle ear and extending into mastoid. IV. Tumor filling middle ear, extending into the mastoid or through tympanic membrane to fill the external auditory canal; may extend anterior to carotid.

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Jugulo-tympanic Paraganglioma 

Classifications:

Glasscock-Jackson Classification:

Glomus Jugulare: I: Small tumor involving jugular bulb, middle ear, and mastoid. II: Tumor extending under internal auditory canal; may have intracranial extension (ICE). III: Tumor extending into petrous apex; may have ICE. IV: Tumor extending beyond petrous apex into clivus or infratemporal fossa; may have ICE.

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Jugulo-tympanic Paraganglioma 

Classifications:

Fisch Classification:

Class A: Middle ear, strictly promontory. Class B: Tympano-mastoid area. Class C: Carotid: C1: Carotid Foramen. C2: Vertical segment of carotid canal. C3: Horizontal segment of carotid canal. C4: Foramen lacerum and cavernous sinus.

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Jugulo-tympanic Paraganglioma 

Classifications:

Fisch Classification:

Class D: Dural: Extra-dural: De1: Intracranial Extra-dural extension < 2cm. De2: Intracranial Extra-dural extension > 2cm. Intra-dural: Di1: Intracranial Intra-dural extension < 2cm. Di2: Intracranial Intra-dural extension > 2cm.

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Jugulo-tympanic Paraganglioma 

Treatment Modalities:

No Treatment and follow up.

Surgical resection.

Primary radiotherapy.

Surgical resection + radiotherapy.


Jugulo-tympanic Paraganglioma 

Wait and See:

Old patient with:

Minimal symptoms.

Repeated CT scans do not show extensive spread or rapid growth.


Jugulo-tympanic Paraganglioma 

Surgery with pre-operative embolization:

Fisch type (A) - Glomus tympanicum I:

Trans-canal excision.

Fisch type (B) – Glomus tympanicum II-IV:

Extended facial recess approach.

Fisch type (C) and (D) – Glomus Jugulare I-IV:

Infratemporal fossa approach (Fisch type A approach).


Jugulo-tympanic Paraganglioma Why would a perfectly normal surgeon go to the Dark Side ?!


Jugulo-tympanic Paraganglioma 

Radiotherapy:

Primary treatment: (controversial)

35Gy/3wks or 45Gy/4weeks is used alone in symptomatic growing tumors with unfitness for surgery . 40% of tumors continue to grow after irradiation.

Adjuvant Radiotherapy:

Especially if complete removal is not possible.

Neo-adjuvant Radiotherapy:

Now replaced be embolization.


Gamma Knife Radiosurgery


Carotid Body 

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Connected to carotid bifurcation by ligament of Mayer. Average size 5 x 3 x 1.5mm.Size increases with age and associated with high altitude dwellers. Blood supply from 1-2mm artery arising from bifurcation. Supplied by the Nerve of Hering, which is a branch of the glossopharyngeal nerve. Minor input from CN X and sympathetic trunk. Functions as a chemoreceptor complex.


Carotid Body Tumor 

Can cause symptoms by physically expanding and compressing surrounding structures, especially nerves, and can be lethal if untreated.

May present with hoarseness, VC paralysis, dysphagia, local discomfort, Headache , blurred vision.

Inheritance is autosomal dominant.


Carotid Body Tumor 

Commonly occurs in the 5th decade.

Higher incidence in females.

Typically present as a slow growing painless neck mass, which is mobile antero-posteriorly, but immobile cranio-caudally.

May bulge through parapharyngeal area into oral cavity or oropharynx.


Carotid Body Tumor 

Differential Diagnosis:

Lymph node. Salivary gland tumor. Neurofibroma, neuroblastoma. Carotid aneurysm. Plasmacytoma. Hemangiopericytoma, myoblastoma. Angioendothelioma, chromaffinoma, endothelioma. Angioma, Angiosarcoma, carcinoid, carcinoma, sarcoma.

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Carotid Body Tumor (Work-Up) 

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MRI, CT with contrast & angiogram are the mainstay. Typical Lyre sign and tumor blush seen on angiography. Balloon test occlusion is performed to evaluate circle of Willis. FNA is not advised as excessive bleeding will occur. Typically non-diagnostic due to excess blood in specimen. Urine VMA, catecholamines. Abdominal CT if symptoms of excess catecholamines.


Carotid Body Tumor (Work-Up) 

If familial, must evaluate for MEN syndromes.

If familial, risk individuals older than 16-18 yrs should be examined and screened with MRI every 2 years.

Genetic screening emerging as a method of evaluation (chromosome 11q13 and q23).


Carotid Body Tumor (Work-Up)


Carotid Body Tumor 

Shamblin classification:  I:

tumors small and easy to remove.

 II:

tumors medium size , with attachment to carotid.

 III:

large with transmural invasion of carotid requiring resection and grafting.


Carotid body tumor (Management) 

Surgery is the mainstay for management.

If excised, may recur in 10% of cases.

Generally regarded as radio-resistant, XRT reserved for incompletely excised tumors ( with intracranial extension), very large tumors, elderly patient, poor surgical candidates, or multicentricity.

Overall operative mortality of 2-8%, stroke rate of 20%, CN X and XII damage rate of 40-50%.


Carotid body tumor (Management) 

Post-operative denervation with sympathetic discharge can lead to high and fluctuating blood pressure.

Managed with nitroprusside initially, then Clonidine (central α-2 agonist), phenoxybenzamine (α-1 blockade) in about 3 – 4 days post-operatively.


Carotid body tumor ( Surgical Pearls) 

Exposure must be liberal and adequate so that control of the vessel proximal and distal to lesion is possible.

Identify CN IX, X, XI, XII , Sympathetic chain.

Be prepared to resect the carotid and graft ( have vascular surgery on stand-by).

Be prepared for fluctuations in blood pressure during and after resection.


Intravagal Paraganglioma 

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Most commonly occur at the level of the nodose ganglion. Mean age of presentation is 50 yrs. More common in females than males. Painless mass posterior to angle of mandible. May bulge into pharynx and cause dysphagia. Complaints of tongue weakness, hoarseness, horner’s syndrome ( Jugular foramen syndromes). Malignancy rate higher than others, estimated at 18%.


Intravagal Paraganglioma


Intravagal Paragangliomas 

Imaging studies include CT and MRI.

Angiography demonstrates tumor blush and displacement of ICA anteriorly and medially ( no widening of bifurcation).

Only one functional vagal paraganglioma was reported.


Intravagal Paraganglioma  

Staging System for Glomus Vagale Tumors: I: Tumors that lie in the parapharyngeal space without invasion of the jugular foramen.

II: Tumors that invade the jugular foramen without bone destruction.

III: Tumors that deeply invade the jugular foramen and middle ear with bone destruction and variable involvement of the carotid canal.

"i" for an isolated tumor without other tumors, and "m” for multiple tumors.


Intravagal Paraganglioma (Management)  

Controversial as to best therapy. Surgery proponents offer this choice as best possibility for complete removal. Surgery resection by trans-cervical approach, combined with lateral skull base approach depending on extent. XRT proponents site morbidity from surgery as prohibitive. XRT has not been shown to be curative, and has risk of Osteo-radionecrosis of temporal bone.


The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires. Ward

Willian Arthur


By Basim Metwally 30/03/2010


glomus