Introduction: A mycotic aneurysm is a bacterial, fungal, or viral infection of the vessel wall. Patients present with an enlarging mass, pain and fever. Risk factors include bacteremia, local injury and bacterial inoculation into the vasculature or spread of existing infections. Treatment includes prolonged antibiotic therapy and endovascular grafting or open surgical repair, with open repair carrying a 20% mortality rate. Untreated, they carry a 60% risk of rupture. Mycotic aneurysms involving the internal carotid artery are extremely rare.
Description: A 69-year-old woman with a history of CREST syndrome, previous total parenteral nutrition and rheumatoid arthritis on rituximab, methotrexate and Solu-Medrol through a right internal jugular port was admitted for concerns of sepsis and Escherichia coli bacteremia. Possible sources included pneumonia and enteritis, but imaging was not strongly supportive of these diagnoses. She reported tender, enlarged lymph nodes on her neck for several months, which also worsened her dysphagia. A firm, tender right-sided cervical mass was palpated on exam. A non-contrast computed tomography scan revealed a dilated right internal jugular venous thrombus with surrounding gas, concerning for line-associated septic thrombophlebitis. She underwent port removal but developed significant tenderness requiring escalating pain medications. Emergent computed tomography angiography revealed a fusiform dilation of the right carotid bulb/origin of the right internal carotid artery, measuring 2.1 × 2.4 × 2.7 centimeters and a 3.9 × 3.9 × 7.3-centimeter fluid collection containing gas surrounding the right carotid bulb, likely involving the right internal jugular vein. The patient was diagnosed with a mycotic aneurysm with a complicated surrounding abscess by vascular surgery. She was emergently transferred to a tertiary care center, where she underwent successful ligation of the right internal carotid artery.
Discussion: This patient had been reporting an enlarged neck mass for several months with no further work up pursued. Had the aneurysm gone undiagnosed, she would have suffered fatal consequences. Although rare, particularly in the internal carotid artery, mycotic aneurysms should be considered in the differential diagnosis of patients presenting with painful neck masses.
