These tumors predominantly affect middle-aged females. In a study conducted by Sarookhani et al. involving 42 patients, 80.96% were female, with an average age of 54.41 years, which aligns closely with the findings of this study [8].
The condition typically manifests as a gradually enlarging, pain-free lump in the neck. It is often detected by chance during imaging procedures. Additional symptoms may involve tinnitus, persistent coughing, changes in voice quality, loss of sensation, Horner syndrome, prickling sensations, impairments related to cranial nerves, difficulty swallowing, localized sensitivity, increased heart rate, and sensitivity to light [8]. In this study, 80% (20 cases) presented with neck swelling, the remaining patients (5, 20%) were asymptomatic, and the disease was found accidentally. Other mentioned manifestations were not found; this may be due to a small sample size of this study.
The CBTs were categorized for the first time in 1971 by Shamblin et al. into three groups based on their relationship with the adjacent blood vessels: small tumors that were confined to a specific area without significant attachment to the vessels (Type I), tumors that were attached to and partially encased the carotid vessels (Type II), and tumors that closely enveloped the carotid vessels (Type III) [7]. Type II is the most common type presented to vascular clinics [7]. This is in agreement with the findings of this study.
A retrospective analysis by Jiang et al. over a decade identified risk factors for postoperative cranial nerve injury in patients undergoing surgical treatment for CBTs. The study included 196 patients with 203 CBTs, revealing that 28.1% experienced cranial nerve injury after surgery. Significant correlations were found between postoperative nerve injury and factors such as Shamblin classification, external carotid artery ligation, internal carotid artery reconstruction, tumor volume, and blood loss. Multivariate logistic regression analysis identified Shamblin III classification and the number of lymph nodes removed as independent risk factors for nerve injury [9]. The present study showed no permanent neurological deficit, but a temporary neurological deficit was found in 12% of the cases. The lower rate of postoperative complications in this study might be explained by the lower rate of the type III CBTs.
The malignancy rate of CBTs hovers around 5 to 7%, with a higher occurrence observed in younger patients, and sporadic tumors also exhibit this trend. Detection of CBT cells in regional lymph nodes raises suspicion of malignancy. This type of tumor can infiltrate nearby nerves, blood vessels, and even the skull. The external carotid artery is frequently affected. Metastases may spread to organs such as the brachial plexus, cerebellum, kidney, thyroid, breast, lungs, bones, and pancreas. Nerves, including the vagal, glossopharyngeal, accessory, and hypoglossal, which traverse the carotid sheath, may become involved. The clinical behavior of the tumor is the primary indicator of its malignancy. Although not definitively confirmed, several studies suggest a higher occurrence in females [8, 10]. In this study, no malignant tumor was reported.
Surgical removal is the primary treatment option, as the tumor carries malignant potential and should be excised before it grows larger and becomes more challenging to remove. As the tumor exhibits high vascularity, intraoperative bleeding emerges as the primary concern, and the tumor's characteristics hinder the efficacy of electrosurgery. While the tumor does not respond well to radiotherapy, it may be considered to control its growth in cases where surgery is not feasible [7]. All of the cases in this study were managed by surgical resection under general anesthesia. Risks of bleeding were minimized by applying several non-vascular clamps, and frequently, the angle of dissection was changed.
Surgical complications, both immediate and delayed, encompass early stroke, necessity for emergency hematoma drainage, temporary impairment of cranial nerves, and delayed issues such as Horner's syndrome, pseudoaneurysm, permanent cranial nerve damage, and delayed stroke [8, 11].
Mortality rates from CBT range from zero to 5.7%. Deaths typically result from local extension before surgery, intraoperative stroke, and blood loss. This study didn’t document any cases of mortality [12, 7]