[Paragangliomas in the head-/neck region. I: Classification and diagnosis]

Novel insights into the classification of Shamblin III carotid body tumors from a neurosurgical perspective

BACKGROUND AND PURPOSE

The classic Shamblin system fails to provide valuable guidance in many Shamblin's III carotid body tumors (III-CBTs) due to the variable forms of carotid arteries and the complex anatomic relationships in parapharyngeal space. We proposed a modified classification to separately divide III-CBTs into different subgroups on the basis of arterial relevant features and anatomical relevant features.

MATERIALS AND METHODS

From 2020 to 2023, a total of 129 III-CBTs at a single institution were retrospectively analyzed. All cases were independently classified as arterial-relevant and anatomical-relevant subgroups. The pre-, peri- and postoperative data were summarized and compared accordingly.

RESULTS

Among the 129 cases, 69 cases were identified as "Classical type", 23 cases as "Medial type", 27 cases as "Lateral type" and 10 cases as "Enveloped type" according to arterial morphologies. Besides, 76 cases were identified as "Common type", 15 cases as "Pharynx- invasion type", 18 cases as "Skull base-invasion type" and 20 cases as "Mixed type" according to anatomical relationships. "Enveloped type" of tumors in arterial-relevant classification and "Mixed type" of tumors in anatomical-relevant classification are the most challenging cases for surgeons with the lowest resection rate, highest incidence of carotid arteries injury and postoperative stroke.

CONCLUSION

The modified classifications provide comprehensive understanding of different III-CBTs which are applicable for individualized treatment in clinical practice.

Long-Term Survival of Bifocal Paraganglioma: A Case Report

Paragangliomas are sympathetic and parasympathetic para-ganglia neuroendocrine tumors of the autonomic nervous system. We analyzed a bifocal paraganglioma case of a 52-year-old patient in December 2013 with hearing loss and right ear pain, headaches, episodes of vomiting, and abdominal pain ten months before her medical consultation. The diagnosis of a right tympano-jugular glomus paraganglioma was based on cerebral magnetic resonance imaging and treated with radiotherapy. In 2016, the patient presented with worsening digestive symptoms; therefore, a second mesocolic localization was suspected by abdominal computed tomography and was histologically confirmed on the resection specimen of the mass. The surgery was the only treatment. After a follow-up of 11 years, the patient remained in good condition. Paraganliomas are rare tumors, their bifocal location in our patient represents an even rarer entity. Given the nonspecific symptomatology, the diagnosis of the retroperitoneal location simultaneously with that of the head and neck was difficult. Our objective is to emphasize the staging workup for paraganglioma, although it is mostly a benign tumor with slow growth.

Stereotactic radiosurgery for head and neck paragangliomas: a systematic review and meta-analysis

Head and neck paragangliomas (HNPs) are rare, usually benign hyper vascularized neuroendocrine tumors that traditionally have been treated by surgery, with or without endovascular embolization, or, more recently stereotactic radiosurgery (SRS). The aim of our study is to determine the clinical and radiographic effectiveness of SRS for treatment of HNPs. A systematic search of electronic databases was performed, and 37 articles reporting 11,174 patients (1144 tumors) with glomus jugulare (GJT: 993, 86.9%), glomus tympanicum (GTT: 94, 8.2%), carotid body tumors (CBTs: 28, 2.4%), and glomus vagale (GVT: 16, 1.4%) treated with SRS definitively or adjuvantly were included. The local control (LC) was estimated from the pooled analysis of the series, and its association with SRS technique as well as demographic and clinical factors was analyzed. The median age was 56 years (44-69 years). With a median clinical and radiological follow-up of 44 months (9-161 months), LC was 94.2%. Majority of the patients (61.0%) underwent Gamma Knife Radiosurgery (GKS), but there was no statistically significant difference in LC depending upon the SRS technique (p = 0.9). Spearmen's correlation showed that LC was strongly and negatively correlated with multiple parameters, which included female gender (r = - 0.4, p = 0.001), right-sided tumor (r = - 0.3, p = 0.03), primary SRS (r = - 0.5, p ≤ 0.001), and initial clinical presentation of hearing loss (r = - 0.4, p = 0.001). To achieve a LC ≥ 90%, a median marginal dose (Gy) of 15 (range, 12-30 Gy) was required. The results corroborate that SRS in HNPs is associated with good clinical and radiological outcome.

[Interventional radiology in the head and neck region]

In interventional neuroradiology, endovascular embolization represents an important and helpful tool in the treatment of multiple head and neck diseases. These interventional procedures may be performed with curative intent, to reduce the surgical risk within a multimodal treatment concept, or to improve or at least maintain a good quality of life within a palliative therapy concept. In addition to a good understanding of disease pathology, knowledge of vascular anatomy, including collateral vessels and dangerous extracranial-intracranial anastomoses, is essential for successful treatment, as is implementation of an established technique using appropriate material. Indications for endovascular embolization are i. otherwise unmanageable bleeding (caused by e. g., trauma, vascular malformation, or tumor), ii. reduction of perioperative bleeding by preoperative embolization in case of a hypervascularized tumor, iii. selective induction of tumor necrosis by palliative embolization to enhance local tumor control. Major complications such as stroke, loss of vision, and cranial nerve palsy are mostly due to a lack of preinterventional evaluation. Regarding neurological deficits, interventions within the supply region of the external carotid artery have a complication rate below 1%.

Instability of succinate dehydrogenase in SDHD polymorphism connects reactive oxygen species production to nuclear and mitochondrial genomic mutations in yeast

AIMS

Mitochondrial succinate dehydrogenase (SDH) is an essential complex of the electron transport chain and tricarboxylic acid cycle. Mutations in the human SDH subunit D frequently lead to paraganglioma (PGL), but the mechanistic consequences of the majority of SDHD polymorphisms have yet to be unraveled. In addition to the originally discovered yeast SDHD subunit Sdh4, a conserved homolog, Shh4, has recently been identified in budding yeast. To assess the pathogenic significance of SDHD mutations in PGL patients, we performed functional studies in yeast.

RESULTS

SDHD protein expression was reduced in SDHD-related carotid body tumor tissues. A BLAST search of SDHD to the yeast protein database revealed a novel protein, Shh4, that may have a function similar to human SDHD and yeast Sdh4. The missense SDHD mutations identified in PGL patients were created in Sdh4 and Shh4, and, surprisingly, a severe respiratory incompetence and reduced expression of the mutant protein was observed in the sdh4Δ strain expressing shh4. Although shh4Δ cells showed no respiratory-deficient phenotypes, deletion of SHH4 in sdh4Δ cells further abolished mitochondrial function. Remarkably, sdh4Δ shh4Δ strains exhibited increased reactive oxygen species (ROS) production, nuclear DNA instability, mtDNA mutability, and decreased chronological lifespan.

INNOVATION AND CONCLUSION

SDHD mutations are associated with protein and nuclear and mitochondrial genomic instability and increase ROS production in our yeast model. These findings reinforce our understanding of the mechanisms underlying PGL tumorigenesis and point to the yeast Shh4 as a good model to investigate the possible pathogenic relevance of SDHD in PGL polymorphisms.

The presence of SDHB mutations should modify surgical indications for carotid body paragangliomas

OBJECTIVE

The aim of this study was to determine whether the genetic background of the disease should be incorporated into treatment decision making.

BACKGROUND

Carotid body paragangliomas are rare tumors that often affect patients with genetic mutations of the succinate dehydrogenase complex (SDHx). Despite growing evidence that germ line genetic mutations alter the aggressiveness of paragangliomas, treatment decisions are currently based only on clinical symptoms and tumor size in patients with carotid body paragangliomas.

METHODS

Retrospective analysis of 34 patients with carotid body paragangliomas who underwent genetic testing and surgical treatment. Recurrence was defined by the return of locoregional disease and/or development of distant metastases. Clinical characteristics and genetic testing results were analyzed as predictors of patient outcomes.

RESULTS

Thirty-four patients underwent 41 primary carotid body paraganglioma resections (median follow-up time of 42 months, range: 1-293). Overall survival was 91.2%. Twelve patients had germ line mutations in SDHB, 17 in SDHD, and 5 carried no known mutation. Surgical resection of larger tumors was associated with higher operative complications (odds ratio: 5.4, P = 0.05). Tumor size at resection was significantly smaller in patients with SDHB mutations than in patients with non-SDHB mutations (2.1 vs 3.3 cm, P = 0.02). Patients with a mutation in the SDHB gene also had significantly worse disease-free survival compared with patients without an SDHB gene mutation (P = 0.03).

CONCLUSIONS

Mutations in the SDHB gene are associated with worse disease-free survival after resection in patients with carotid body paragangliomas despite earlier intervention. This suggests that a more aggressive surgical approach is warranted in patients with SDHB mutations.

SDHB gene mutation in a carotid body paraganglioma: case report and review of the paraganglioma syndromes

Carotid body tumors represent the most common of head and neck tumors. They account for <0.03% of all human tumors. The underlying physiology and pathogenesis of this tumor type are not well understood. Several different genetic abnormalities have been associated with the development of carotid body paragangliomas. We present a case report with an unusual genetic mutation in the SDHB gene and a review of the paraganglioma syndromes.

Choroidal paraganglioma with metastases to the fellow eye

Purpose

To report a case of a paraganglioma in the right eye with metastatic disease in the fellow eye 3 years later.

Methods

A 70-year-old man presented with a painful amblyopic right eye; rubeosis iridis and a large choroidal tumor were found. The tumor was treated by enucleation. Pathology diagnosed the tumor as a paraganglioma. Screening for other tumors or metastatic disease was negative at that moment. After 3 years, a paraganglioma skin metastasis was detected, and screening revealed metastatic disease in the liver. Another 6 months later he was referred for tumors in the left eye, which were treated by radiotherapy. He succumbed 6 months later.

Results

Histopathology of the right eye revealed the typical image of a paraganglioma, with expression of synaptophysin, neuron-specific enolase and chromogranin. S-100 staining was positive in the sustentacular cells; staining for HMB-45, SME, EMA and pan-keratin was negative. Microscopy of the tumors in the skin and liver 3 years later showed a dedifferentiated tumor with the same immunological characteristics, but with higher Ki67 expression and more mitoses.

Conclusions

This report documents a very rare choroidal paraganglioma which presented clinically as a melanoma. The patient succumbed 4 years later to generalized metastatic disease. No other primary paraganglioma was found; however, paraganglion cells in the eye have never been described.

Paragangliomas and paraganglioma syndromes

Paragangliomas are rare tumors of neural crest origin. They are benign in the majority of cases and are characterized by a strong vascularisation.

In the head and neck region they most commonly occur as carotid body tumors. Jugulotympanic and especially vagal paragangliomas are seen less frequently. Complete surgical resection represents the only curative treatment option even though resection of locally advanced tumors regularly results in lesions of the lower cranial nerves and major vessels.

Appoximately 30% of all head and neck paragangliomas (HNPs) are hereditary and associated with different tumor syndromes. The paraganglioma syndromes 1, 3 and 4 (PGL 1, 3 and 4) make up the majority of those familial cases. PGL 1 is associated with mutations of the succinate dehydrogenase subunit D (SDHD) gene, PGL 3 is caused by SDHC and PGL 4 by SDHB gene mutations. Multiple HNPs and the occurance of HNPs together with pheochromocytomas are seen in SDHD as well as SDHB mutation carriers. In patients with SDHB mutations the risk for the development of malignant paraganglial tumors is significantly higher compared to SDHC and SDHD patients as well as patients with sporadic tumors. SDHC mutation carriers almost exclusively present with benign HNP that are unifocal in the majority of cases. The role of transmission is autosomal dominant for all three symptoms. Interestingly, there is a “parent-of-origin-dependent-inheritance” in subjects with SDHD gene mutations. This means that the disease phenotype may only become present if the mutation is inherited through the paternal line. We recommend screening for mutations of the genes SDHB, SDHC and SDHD in patients with HNPs. Certain clinical parameters can help to set up the order in which the three genes should be tested.

Juxtacondylar approach in temporal paraganglioma surgery: when and why?

As it became clear that patients with paraganglioma (PGL) syndromes had a higher risk of multifocal tumors, we changed our surgical strategy to avoid the possibility of bilateral cranial nerve paralysis. The juxtacondylar approach offers advantages for some jugular foramen tumors, including types C and D temporal PGLs. This approach allows exposure of the jugular foramen without skeletonizing or transposing the facial nerve. It improves the surgeon's ability to distinguish between the pars vascularis and the pars nervosa at the jugular foramen, and it helps to save functioning of the lower cranial nerves. There is already considerable experience using the juxtacondylar approach for patients suffering from schwannomas and meningiomas involving the jugular foramen. Some limitations have been noted for using the juxtacondylar approach with jugular PGLs that are related to their vascular nature. In this article we demonstrate its use for the management of eight patients with locally advanced temporal PGLs and how it can be combined with an infratemporal fossa approach.

[Unilateral tongue atrophy and articulation difficulties]

A 24-year-old female complained of difficulty articulating and chewing of 2 more than weeks' standing. She reported that her tongue felt "heavy and inert". Clinically, right-sided atrophy of the tongue and deflection of the tongue to the right were observed. Tone audiogram demonstrated normal hearing on both sides and tympanometry was also normal. On CT, a bone-destroying process was seen in the area of the right lateral skull base, which reached as far as the internal carotid artery. MRI demonstrated atrophy of the right tongue musculature with fatty degeneration, as well as an oval, smoothly edged lesion which showed marked contrast-medium uptake with a "salt and pepper" configuration in the region of the right jugular foramen. The diagnosis was hypoglossal paresis due to ipsilateral jugular paraganglioma (Fisch classification C1). Following embolization of the feeding vessels of the paraganglioma, the tumor was completely resected, including the hypoglossal nerve which ran through the tumor. Postoperative dysfunction of the vagus and facial nerves became unsymptomatic with time as a result of logopedic therapy.