Teaching Case

A comatose 35-year-old female patient was transferred to our emergency room from a private plastic surgery hospital by its working staff. GCS was scored 3. Brain CT showed multiple low-density strips or dots within vessels. The staff admitted she had received autologous fat injection in temporal sites for cosmetic purpose in their hospital, but could not recover from anaesthesia after surgery.

Figure 1. Brain CT shows multiple hypodensities within cerebral arteries. HU ranges from -26 to -15. Air or fat embolism was considered. Figure 2. A. Contrast-enhanced brain CT shows normal enhancement in right MCA (white arrow) and non-enhancement in the Willis circle, bilateral ACA, left MCA and BA. B. Autologous fat fillers can be observed beneath temporal skin (wide arrows). C. CT angiography shows right ICA, right MCA and VAs. Other arteries are invisible. D. CT perfusion reveals diminished cerebral blood volume in all but right MCA region. Midbrain and pons are also involved.

ICA, internal carotid artery; ACA, anterior cerebral artery; MCA, middle cerebral artery; BA, basilar artery; VA, vertebral artery.

Background
Autologous fat transplantation is a procedure in plastic surgery for soft-tissue correction, augmentation, and reconstruction. Brain infarction is a rare complication of this procedure. [1] Autologous fat is usually injected in the temporal region, just like this patient. Superficial temporal artery, a branch of external carotid artery goes beneath the temporal site. If the fat is injected into the superficial temporal artery, it will retrograde into the external carotid artery, common carotid artery and then antegrade into the internal carotid artery, resulting in cerebral embolism.
Clinical Perspective
Brain infarction due to autologous fat injection usually causes variable but mild symptoms. However, cases of massive cerebral infarction that needs decompressive craniectomy to save lives were reported. [2-6] In these cases, the injection sites were all temporal regions. It is worrisome that similar reports in the past five years were all from China. [2-6] Discerning it from the many problems that causes unconsciousness in peri-operation period is challenging. In this setting, diagnosis largely depends on radiological profiles. Since the plastic and cosmetic surgery prevails in China, physicians should be vigilant when a patient is transferred from plastic surgery department or hospital.
Imaging Perspective
Cerebral CT scan is a preferred tool. Hypodensity within vessels can be air or fat embolism. Illness history provides clues. Air embolism is usually seen in scuba divers. Conventional fat embolism develops after orthopaedic injury and surgery. Autologous fat transplantation emerges as a new possibility. MCA is the most frequently affected vessel. But when fat injection is performed too quickly and forcefully at external carotid arteries region, the internal carotid arteries may be occluded. CT angiography and CT perfusion can provide additional information about the vessels. The diagnosis is based on both illness history and radiological profiles.
Outcome
In this case, brainstem infarction was present due to basilar artery occlusion. Decompressive craniectomy will not save her life. As a result, the prognosis was very poor. The patient died 12 hours later. This is the only fatal case due to autologous fat cerebral embolism in English literature.
Take Home Message / Teaching Points
Cerebral embolism is a rare complication of fat injection, but maybe not that rare in China these days.
CT scan is a useful tool to detect fat embolism. A major differential diagnosis is air embolism.
CT angiography and CT perfusion are helpful to evaluate severity of the disease.
Background
Autologous fat transplantation is a procedure in plastic surgery for soft-tissue correction, augmentation, and reconstruction. Brain infarction is a rare complication of this procedure. [1] Autologous fat is usually injected in the temporal region, just like this patient. Superficial temporal artery, a branch of external carotid artery goes beneath the temporal site. If the fat is injected into the superficial temporal artery, it will retrograde into the external carotid artery, common carotid artery and then antegrade into the internal carotid artery, resulting in cerebral embolism.
Clinical Perspective
Brain infarction due to autologous fat injection usually causes variable but mild symptoms. However, cases of massive cerebral infarction that needs decompressive craniectomy to save lives were reported. [2-6] In these cases, the injection sites were all temporal regions. It is worrisome that similar reports in the past five years were all from China. [2-6] Discerning it from the many problems that causes unconsciousness in peri-operation period is challenging. In this setting, diagnosis largely depends on radiological profiles. Since the plastic and cosmetic surgery prevails in China, physicians should be vigilant when a patient is transferred from plastic surgery department or hospital.
Imaging Perspective
Cerebral CT scan is a preferred tool. Hypodensity within vessels can be air or fat embolism. Illness history provides clues. Air embolism is usually seen in scuba divers. Conventional fat embolism develops after orthopaedic injury and surgery. Autologous fat transplantation emerges as a new possibility. MCA is the most frequently affected vessel. But when fat injection is performed too quickly and forcefully at external carotid arteries region, the internal carotid arteries may be occluded. CT angiography and CT perfusion can provide additional information about the vessels. The diagnosis is based on both illness history and radiological profiles.
Outcome
In this case, brainstem infarction was present due to basilar artery occlusion. Decompressive craniectomy will not save her life. As a result, the prognosis was very poor. The patient died 12 hours later. This is the only fatal case due to autologous fat cerebral embolism in English literature.
Take Home Message / Teaching Points
Cerebral embolism is a rare complication of fat injection, but maybe not that rare in China these days.
CT scan is a useful tool to detect fat embolism. A major differential diagnosis is air embolism.
CT angiography and CT perfusion are helpful to evaluate severity of the disease.
This patient is deceased and has no family members. Written patient consent for this case was waived by the Editorial Board. Patient data may have been modified to ensure patient anonymity.