A Case of Shamblin III Carotid Body Tumor

Carotid body tumors (CBTs) arise from the chemoreceptor cells located at the base of the carotid arteries. Due to their proximity to crucial structures, CBTs are diagnostic and therapeutic challenges. Most of these tumors are benign; however, a small proportion of these malignant tumors have a good survival rate. Shamblin classified these tumors based on their local spread into three stages. This case report describes the complexities of a Shamblin III CBT. A woman in her mid-40s presented with a 13-year history of a slow-growing, painless lump on the left side of her neck, which had gone unnoticed until it reached a size of considerable magnitude. She did not have any concerning symptoms, such as fever, sore throat, weight loss, or night sweats. There were no other red flag symptoms, and her past medical history was unremarkable. There was no history suggestive of exposure to tuberculosis. During the examination, the patient was vitally stable and presented with an obvious, irregularly shaped, pulsatile, firm, and smooth mass on the left lateral portion of the neck that measured 6×3 cm. The mass also had an audible bruit. The other parts of the neck examination were also unremarkable, and there was no lymphadenopathy. Differential diagnosis in this case would include lipoma, cystic lesion, malignancy in the head and neck, and CBT. Baseline investigations, along with serological tests, were normal. As per computed tomography (CT) angiography findings, a 5.5×6.3×8.5 cm mass was found in the left carotid space. This mass was enhancing, splitting the internal and external carotid arteries on both sides and completely enclosing the bifurcation of the carotids along with their tributaries. This was classified as a Shamblin III CBT. The size and location of the encapsulating mass warranted a definitive surgical approach. The procedure was carried out as a planned excision under general anesthesia. After general risk counseling and the acquisition of informed consent, the anterior border of the sternocleidomastoid muscle was incised. Once the carotid sheath was exposed and the internal jugular vein retracted, the mass was visible. The encapsulating mass was closely surrounding the common, internal, and external carotid arteries. Care was taken during the resection of the mass to preserve the surrounding structures. The mass was completely resected along with the distal end of the external carotid artery. A Javid shunt was placed, and then the shunt was removed. After hemostasis, the wound was reapproximated, and the mass was sent for complete pathological review. The patient remained in the hospital for four days and showed uneventful progression. She was discharged on the fourth postoperative day. Considering a broad differential diagnosis for painless neck masses is important. For Shamblin III CBTs, imaging is critical in diagnosis, formulating a preoperative plan, and understanding the extent of difficulties posed by the excision of these vascular tumors. Surgical excision, which is highly challenging, is still the best approach to take to treat these tumors.