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GLOMUS TUMORS . Department of Otorhinolaryngoglogy 2nd Hospital affliatted to Medical college of Zhejiang University Xu Yaping. Definition. Glomus tumors are generally benign neoplasms of arising from neuroectodermal tissues, found in various parts of the body. . Pathology.
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GLOMUS TUMORS Department of Otorhinolaryngoglogy 2nd Hospital affliatted to Medical college of Zhejiang University Xu Yaping
Definition • Glomus tumors are generally benign neoplasms of arising from neuroectodermal tissues, found in various parts of the body.
Pathology • catecholamine + sustentacular cells (modified Schwann cells) +a rich network of capillaries and venules.---- "zellballen" • "light" and "dark" cell subpopulations, referring to the density of intracellular neurosecretory granules. • Chief cells are members of the amine precursor and uptake decarboxylase (APUD) family, as the DNES (diffuse neuroendocrine system). • related to the adrenal medulla, and their neoplastic counterpart in the adrenal gland is the pheochromocytoma.
The extra-adrenal versions have various names including non-chromaffin paragangliomas, • aragangliomas, chemodectomas, • glomerocytomas, • receptomas, • tympanic body tumors, • carotid body tumors, • and a few others.
Synchronous glomus tumors are not the only associated neoplasms. • Several authors have reported an association with other neoplasms (benign and malignant). Spector et. al. reported a 7% incidence in his series of 95 patients. thyroid C-cell carcinoma, parathyroid adenomas, pheochromocytomas, the MEN syndromes, visceral neoplasms of neural crest origin.
In the head and neck, two anatomic groups of paragangliomas can be differentiated: • cervical paragangliomas • temporal bone ( jugulotympanic) paragangliomas.
The cervical group includes primarily carotid body tumors glomus vagale or intravagale tumors, • The jugulotympanic refers to glomus jugulare glomus tympanicum tumors. ---------the second most common temporal bone tumors The firstis the acoustic neurinomas.
Epidemiology • The incidence of glomus jugulare tumors is 1:1,300,000 population. • the predominant incidence in females. The female:male incidence ratio is at least 4:1. • The incidence of malignancy in glomus tumors is believed to be low (<5%). • Patient age averages 50 to 60 years , and highly variable. • Catecholamine secreting ( "functional") tumors occur in 1% - 3% of cases. • There is no racial or ethnic predilection.
Clinical Presentation • Symptoms are insidious in onset. • pulsatile tinnitus: most common, tinnitus is secondary to mechanical impingement on the umbo is most cases. • aural fullness, • conductive hearing loss. • Sensorineural hearing loss on the side of a glomus tumor is the hallmark of labyrinthine invasion.
Physical examination • a red or reddish-blue mass seen behind the tympanic membrane. • The diagnosis of glomus tympanicum can only be entertained if the examiner can see a full 360 degrees around the perimeter of the lesion, otherwise the presumptive diagnosis must be a glomus jugulare. • The finding of a middle ear mass is fairly reliable, with 94 - 100% of untreated cases demonstrating this in reviews of large series of patients.
Brown's sign (blanching of the mass with positive pressure pneumotoscopy) is often mentioned, but the frequency of this finding is not clear. • Rarely, a friable or bleeding mass in the EAC may be the presenting sign with larger tumors. • tachycardia, tremor, or complaints of vascular headaches should alert for the possibility of a functional tumor.
Cranial nerve deficits are seen primarily with larger tumors compression or invasion of CN's IX, and X most commonly • CN's VII, VIII, XI, and XII affected less often. • Isolated deficits of CN's VII and VIII are more likely to be secondary to a tympanicum.
Diagnosis and Preoperative Evaluation • clinical grounds: the presumptive diagnosis • CT, MRI: the size and extent • sometimes angiography: the primary blood supply to tumor. • A myringotomy for purposes of obtaining tissue should not be performed on a middle ear mass. • If a tissue biopsy is to be obtained (not usually necessary) a transmastoid approach should be used.
Differential diagnoses • neural lesions (neurolemmoma, neurofibroma, chordoma), osteoblastoma, • adenomas, adenocarcinomas, • inflammatory polyps, • cholesterol granulomas, • rare lesions such as histiocytosis, fibromyxoma, melanoma, rhabdomyosarcoma, lipoma, plasmacytoma, or metastatic lesions (lung, breast, prostate), almost all of these can be excluded with the appropriate physical examination and radiological studies.
Treatment • surgical excision: Glomus Tympanicum The appropriate treatment of glomus tympanicum tumors isolated to the middle ear, middle ear and mastoid, or even the inner ear (Fisch classifications A & B) Glomus tympanicums can be completely excised in over 90% of cases with standard otologic approaches.
Glomus Jugulare: surgical excision, radiation therapy, surgery and radiation, or observation. The argument over the relative merits of surgery vs radiation center on their complications and efficacy. With advances in skull base techniques, surgery is generally efficacious, so the decision on treatment mode often centers on the potential morbidity of the surgery, and other patient factors.
