Glomus Tympanicum

A case report on surgical management of glomus tympanicum and literature review

INTRODUCTION

Glomus tympanicum is a benign tumor classified under the group glomus tumors, and is also known as paragangliomas.

CASE PRESENTATION

A 52 years old woman presented with unilateral pulsatile tinnitus and hearing loss. She had a visible reddish mass behind the eardrum; Temporal bone CT scans suggested middle ear mass secondary to Glomus Tympanicum tumors. With the diagnosis of Modified Fisch-Mattox class A2 middle ear paragangliomas the tumors was surgically removed (7 mm × 5 mm on the right) using post-aural approaches. Histopathology confirmed the diagnosis of paraganglioma. The patient was discharged and being monitored regularly. This report follows the SCARE criteria guidelines.

CLINICAL DISCUSSION

Glomus Tympanicum, a slow-growing, benign tumor originating from paraganglia, is a rare occurrence. It typically presents with pulsatile tinnitus and hearing loss, often unilateral. Early diagnosis and surgical intervention are crucial for optimal outcomes.

CONCLUSION

Glomus tympanicum is a rare condition. There are three treatment options for this condition observation, surgical excision, and radiotherapy. The primary therapeutic option for paragangliomas is complete surgical excision, it is performed under microscopic observation or an endoscopic approach. A timely diagnosis makes surgical treatment more straightforward.

Long-Term Surgical Outcome of Class A and B Tympanomastoid Paragangliomas

OBJECTIVE

To analyze the long-term facial function as well as overall postoperative condition in surgically treated tympanomastoid PGL patients.

STUDY DESIGN

Retrospective study.

METHOD

The medical records of patients with surgically managed class A and B tympanomastoid PGLs between 1983 and 2023 were thoroughly evaluated.

RESULT

Our center has treated a total of 213 cases of tympanomastoid PGL surgically. The mean age of patients was 54, and the male-to-female ratio was 1:6. The most common symptoms at presentation were hearing loss (80%), pulsatile tinnitus (77%), and vertigo (15%). According to the modified Fisch classification, 45% of the cases were classified as class A (A1 and A2), while 55% were classified as class B (B1, B2, and B3). All class A and most class B1 and B2 tumors were removed either with transcanal or retroauricular-transcanal approaches. However, more advanced class B3 lesions were removed with subtotal petrosectomy (SP) along with middle ear obliteration. Facial nerve outcome was excellent in all class A and B cases, while chances of postoperative paresis slightly increased with the size and extent of the tumor (p < 0.05). The hearing outcome is excellent for class A1, A2, B1, and B2 tumors, whereas more advanced class B3 cases have a loss of air conduction (AC) and increased bone conduction (BC) threshold (p < 0.05). Complete surgical removal was achieved in 97% of our cases. The most common late complication was permanent TM perforation (7%), and the recurrence rate was 3%.

CONCLUSIONS

Tympanomastoid PGL represents the most common neoplasm of the middle ear space. The most frequent presenting symptoms include pulsatile tinnitus and hearing loss, whereas the presence of retrotympanic mass was evident in all cases at the time of initial otoscopic evaluation. Proper documentation of facial function and audiometric evaluation are crucial elements of preoperative workup. The most preferred preoperative radiologic examination is high-resolution computer tomography (HRCT), whereas magnetic resonance imaging (MRI) with or without gadolinium enhancement is reserved for cases with a dilemma of carotid artery or jugular bulb involvement. The main goal of tympanomastoid PGL treatment is complete disease removal with preservation of hearing and facial functions. Surgical treatment remains the preferred treatment modality with the benefits of complete disease removal, lower rate of recurrence and complication, and acceptable postoperative hearing level. Here, we present our 40 years of experience, which, to the very best of our knowledge, is the largest series of tympanomastoid PGL in the English literature.

Skull Base Tumors

OBJECTIVE

This article reviews the presenting features, molecular characteristics, diagnosis, and management of selected skull base tumors, including meningiomas, vestibular schwannomas, pituitary neuroendocrine tumors, craniopharyngiomas, chordomas, ecchordosis physaliphora, chondrosarcomas, esthesioneuroblastomas, and paragangliomas.

LATEST DEVELOPMENTS

Skull base tumors pose a management challenge given their complex location and, as a result, the tumors and treatment can result in significant morbidity. In most cases, surgery, radiation therapy, or both yield high rates of disease control, but the use of these therapies may be limited by the surgical accessibility of these tumors and their proximity to critical structures. The World Health Organization classification of pituitary neuroendocrine tumors was updated in 2022. Scientific advances have led to an enhanced understanding of the genetic drivers of many types of skull base tumors and have revealed several potentially targetable genetic alterations. This information is being leveraged in the design of ongoing clinical trials, with the hope of rendering these challenging tumors treatable through less invasive and morbid measures.

ESSENTIAL POINTS

Tumors involving the skull base are heterogeneous and may arise from bony structures, cranial nerves, the meninges, the sinonasal tract, the pituitary gland, or embryonic tissues. Treatment often requires a multidisciplinary approach, with participation from radiation oncologists, medical oncologists, neuro-oncologists, and surgical specialists, including neurosurgeons, otolaryngologists, and head and neck surgeons. Treatment has largely centered around surgical resection, when feasible, and the use of first-line or salvage radiation therapy, with chemotherapy, targeted therapy, or both considered in selected settings. Our growing understanding of the molecular drivers of these diseases may facilitate future expansion of pharmacologic options to treat skull base tumors.

Clinical characteristics and surgical strategy of glomus tympanicum tumors

OBJECTIVES

To summarize the clinical characteristics of glomus tympanicum tumors, and to explore the surgical methods and the strategy for auditory protection.

METHODS

Ten cases (ears) of glomus tympanicum tumors were collected from the Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University from August 2014 to February 2022. All patients underwent endoscopic or microscopic surgery to achieve total removal of the tumor, followed up for 3 months to 8 years. We summarized and analyzed its clinical characteristics, compared the preoperative and postoperative hearing levels of patients, and made a retrospective summary of the surgical methods and the strategy for auditory protection.

RESULTS

Ten patients were all female at (49.50±8.00) years old. Their medical history ranged from 15 days to 6 years. Seven patients complained of pulsatile tinnitus, and 80% (8/10) of the affected ears suffered different degrees of hearing loss. According to the modified Fisch & Mattox classification of glomus tympanicum tumors, 3 ears (30%) of 10 ears were A1, 2 ears (20%) were A2 and 5 ears (50%) were B1. In all 10 cases (ears), hearing was improved in 3 cases, bone gas conductance was maintained in 6 cases, and hearing was slightly decreased in 1 case. The difference of bone gas conductance was 0-10 dB in 7 cases (ears) after operation, and 10-20 dB in 3 cases (ears). There was no significant difference in the average air conduction hearing threshold, bone conduction hearing threshold and air-bone conduction difference between before and after operation (all P>0.05). All cases had no postoperative complications, and the external auditory canal and the incision behind the ear healed well. There was no recurrence after follow-up.

CONCLUSIONS

Glomus tympanicum tumor is easy to bleed, so it is a challenge for total tumor resection and hearing function protection during operation. For type A and type B1 tumors, they can be completely removed under the condition of keeping the tympanic membrane and the ossicular chain. At the same time, the postoperative hearing function can be preserved, and even the hearing can be improved.

A Case for Genetic Testing in Isolated Tympanic Paragangliomas

OBJECTIVE

The aim of this study is to describe two clinical cases, which we believe highlight the need to consider routine genetic testing of all patients with new diagnosis of a tympanic paraganglioma (PGL).

PATIENTS

Two patients seen in the ENT clinic at a tertiary center with a diagnosis of isolated tympanic PGL, without family history.

INTERVENTION

Since 2016, all patients with newly diagnosed isolated tympanic PGL (glomus tympanicum) are offered review by the clinical genetic team and genetic testing of a panel of paraganglioma/phaeochromocytoma predisposition genes. Previously only those with multiple PGL or a family history were tested.

MAIN OUTCOME MEASURES

We describe the results of genetic testing, the clinical course and discuss the ongoing implications for management.

RESULTS

Both cases were identified to have a pathogenic variant in the SDHB gene after initial surgery. The clinical course for both cases was complicated by disease recurrence, as well as metastatic and secretory disease in one case. Knowledge of genetic status has influenced ongoing management, with annual MRI surveillance for other SDH-related tumors.

CONCLUSION

These two cases reinforce the importance of offering genetic testing for all cases of isolated tympanic PGL. The discovery of a significant underlying genetic variant may affect management decisions and subsequent follow-up.

Post-Embolization Excision of Glomus Tympanicum: A Case Report

Glomus tympanicum is a slow-growing benign tumor that can be locally destructive, spreading along the path of least resistance. Conventionally seen as soft tissue mass in the middle ear, it is difficult to distinguish glomus tympanicum from other soft tissue masses of the tympanic cavity, especially as it hides behind an intact tympanic membrane. The primary diagnostic modalities are CT scan and MRI for evaluation of the exact anatomical extent and size of the glomus tumors. Embolization following an angiographic study helps to identify the feeding arteries with subsequent blocking of the same, thus helping in the reduction of intraoperative hemorrhage. The currently available modalities of treatment are mainly surgery and radiotherapy.

Here, we report a case of a 40-year-old female who presented with unilateral deafness and tinnitus, with no co-morbidities. She showed a red bulging mass behind an intact tympanic membrane on otoscopy and otomicroscopy with mild conductive hearing loss. MRI showed an intensely enhancing lesion in the mesotympanum and hypotympanum along the cochlear promontory. A diagnosis of glomus tympanicum was made based on clinical, audiological, and radiological findings. Pre-operative embolization was carried out 48 hours before the surgery. Complete resection of the tumor was achieved by microsurgery.  

Unusual presentation of a large glomus tympanicum with a coexisting cholesteatoma

A glomus tympanicum with chronic infectious otorrhea should have a lower threshold for surgical exploration as an occult cholesteatoma may be present in a location difficult to diagnose without performing a tympanomastoidectomy.

Review of Temporal Bone Microanatomy : Aqueducts, Canals, Clefts and Nerves

Temporal bone microanatomy is a common source of consternation for radiologists. Serpentine foramina, branching cranial nerves, and bony canals containing often clinically relevant but often miniscule arterial branches may all cause confusion, even among radiologists familiar with temporal bone imaging. In some cases, the tiniest structures may be occult or poorly visualized, even on thin-slice computed tomography (CT) images. Consequently, such structures are often either ignored or mistaken for pathologic entities. Yet even the smallest temporal bone structures have significant anatomic and pathologic importance. This paper reviews the anatomy and function of the temporal bone aqueducts, canals, clefts, and nerves, as well as the relevant developmental, inflammatory, and neoplastic processes that affect each structure.

The Forgotten Second Window: A Pictorial Review of Round Window Pathologies

The round window serves to decompress acoustic energy that enters the cochlea via stapes movement against the oval window. Any inward motion of the oval window via stapes vibration leads to outward motion of the round window. Occlusion of the round window is a cause of conductive hearing loss because it increases the resistance to sound energy and consequently dampens energy propagation. Because the round window niche is not adequately evaluated by otoscopy and may be incompletely exposed during an operation, otologic surgeons may not always correctly identify associated pathology. Thus, radiologists play an essential role in the identification and classification of diseases affecting the round window. The purpose of this review is to highlight the developmental, acquired, neoplastic, and iatrogenic range of pathologies that can be encountered in round window dysfunction.

Immunohistochemical Profile of Neurotrophins and MIB-1 in Jugulotympanic Paragangliomas: Prognostic Value and Review of the Literature

Jugulo-tympanic paragangliomas are the most common primary neoplasm of the middle ear, but little is still known about the histological features differentiating the benign and malignant forms. We investigated, with an immunohistochemical procedure, the expression of neurotrophins with their receptors, in fifteen samples of paragangliomas, and MIB-1 in order to consider them as prognostic factors of malignancy. We observed a general positivity for NGF – TrKA – NT4 – TrKC in the cytoplasm, and a strong expression for BDNF in the extracellular space. MIB-1 was moderate in the nucleus of neoplastic cells, weak in the cytoplasm and totally absent in the extracellular space. The comparison between the clinical recurrences and the rate of cytoplasmatic neurotrophins showed strong immunoreactivity in recurrent patients. It should be emphasized that 2 of the 3 recurrences had a wider distribution of the neutrophins, leading to hypothesize the involvement of these substances in the cell proliferation of glomus tumors. Malignant forms of these rare glomus tumors cannot be clearly identified using MIB-1 as a prognostic marker, although we can affirm that neurotrophins and their receptors can be considered as a panel of potential diagnostic markers to monitor the development of such malignancies. Although the small number of patients does not allow definitive conclusions to be made, our findings showed a possible trend towards significance which requires a more powerful study to evaluate this further.