Key-words:
Brainstem lesions - hemiparesis - medulla oblongata - medullary cavernous hemangioma
Introduction
Cavernous hemangiomas are present in about 0.5% of the population.[[1]] The incidence of cavernous malformations in the medulla oblongata is about 5%.[[2]] There is a risk of hemorrhage, significant mortality, and morbidity in these patients.
The patient presents with a variety of symptoms, depending on the level of hemorrhage
and lesion. Surgery is the mainstay of treatment.[[3]]
Case Report
A 31 year old male patient presented with complaints of sudden onset left-sided weakness
with giddiness, imbalance while walking, nasal regurgitation, hiccups, and difficulty
in swallowing. On examination, he was conscious oriented to time, place, and person.
His neurological examination revealed left hemiparesis (grade-4), left facial paresis
(House–Brackmann grade-3), left palatal palsy with decreased gag reflex, and left
vocal cord palsy. His biochemical screening was in the normal limit.
Magnetic resonance imaging brain [[Figure 1]]
There is a lesion in the posterolateral medulla oblongata in the region of the restiform
body, about 14.3 × 16.6 × 16.3 mm (transverse × AP × CC) in size. It is hyperintense
on T1 and shows mixed hypo- and hyperintense signals on T2. There is a thin complete
hemosiderin ring around T2 WI and shows heterogeneous blooming on gradient images.
Minimal edema is seen in the surrounding area which causes mass effect on the fourth
ventricle.
Figure 1: Magnetic resonance imaging of the brain - showing tumor
Ultrasonography of the abdomen and pelvis
Two hyper echoic lesions measuring 2.2 cm and 1.1 cm in segment VIII of right lobe
of liver, suggestive of liver hemangioma.
Procedure and follow-up
The patient was put in the prone position and 3-point fixation was done. A midline
suboccipital vertical incision was taken. Suboccipital bone and C1 arch are exposed.
Suboccipital bone was drilled and excised. Foramen magnum opened. Hemostasis achieved.
Dura opened in “v” manner and cerebrospinal fluid drained by opening cisterna magna.
Cerebellum seen lax and pulsating. Arachnoid opened. Interhemispheric and telovelar
approach was taken. The fourth ventricle opened. Bulge was noted on the lateral wall
of the fourth ventricle. A small opening was made. Clot with hemangioma visualized.
[[Figure 2]] Piecemeal excision was done till the gliotic plane was seen all around. Dura closure
was done using durapatch. Postsurgery, the patient was extubated and monitored during
hospital stay. Histopathological examination revealed dilated spaces around blood
vessels suggestive of cavernous hemangioma. [[Figure 3]] His facial paresis (grade-2) and hemiparesis improved during 1-week postsurgery,
but he continued to have Ryles tube feeds. One-month postsurgery, he was able to ambulate
without support with subtle weakness and was able to tolerate orally without dysphagia.
Figure 2: Intraoperative picture: visualized cavernous hemangioma
Figure 3: Histopathology: Dilated spaces around blood vessels suggestive of cavernous malformation
Discussion
Cavernous hemangiomas of the medulla oblongata are rare presentations. Incidence is
about 5% of all brain stem hemangiomas. Cavernous malformations occur in a sporadic
manner or autosomal dominant inherited conditions. Cerebral malformations present
in the Hispanic population are familial compared to sporadic disease in Caucasians.
Familial cavernous hemangiomas have been attributed to mutations at three different
loci: CCM1 on 7q21.2, CCM2 on 7p15-p13, or CCM3 on 3q25.2-q27.[[4]] As in our case, the patient had hemangioma in the medulla oblongata and also in
the liver which shows genetic predisposition.
The incidence of risk of bleeding is about 2.7%. The risk of rebleeding is about 21%.
The medulla oblongata contains the cardiac, respiratory, vomiting, and vasomotor centers
and regulates autonomic, involuntary functions such as breathing, heart rate, and
blood pressure. It contains corticospinal tracts, ascending sensory tracts of fasciculus
cuneatus, and gracilis with nuclei of VIII, IX, X, XI, and XII nerves. Hence, an important
center for sensory and motor relay with decussation. Hence, hemorrhage in this area
presents with signs of hemiparesis and cranial nerve palsy of IX nerve palsy with
sensory deficit and hemiparesis.[[5]],[[6]] Rare presentations include persistent hiccups.[[7]]
Surgical resection of cavernous hemangiomas is usually selected during the subacute
stage[[8]] because of the favorable dissection plane or gliotic plane, except for patients
who experience severe and progressive neurologic deficits and need emergency surgical
intervention.[[9]] Electrophysiologic monitoring of the cranial nerves and nuclei mapping should be
routinely performed and are useful in gaining precise feedback information intraoperatively
to avoid the direct damage of the critical structure.
Usually, three distinct approaches were applied to the resection of cavernous hemangiomas
involving the medulla oblongata: the far-lateral craniotomy was used for lesions in
the lateral or anterolateral portion of the medulla or the pontomedullary junction;
the retrosigmoid craniotomy was used for lesions in the anterolateral pontomedullary
junction, especially for lesions predominantly located in the pons and posterior sub
occipital craniotomy was used for lesions in the floor of the fourth ventricle or
posterior medulla. The safe entry zone was determined based on the pial presentation,
brainstem anatomic landmarks, intraoperative neuronavigation, and nuclei mapping.[[3]]
Major complications of surgery include deficit of active or passive cough reflexes,
facial palsy, need for gastrostomy in patients having severe dysphagia, tracheostomy,
and ventilator-associated complications. Brain stem cavernous malformations, with
at least one prior symptomatic bleeds or progressive neurological deficits with clearly
superficial pial or ependymal representation are good candidates for microsurgical
resection, which can be reached through a small minimal incision of the brainstem
surfaces without crossing healthy tissue.
The application of new technologies such as intraoperative image navigation and diffusion
tensor imaging could improve the outcome of patients. However, for reducing the likelihood
of postoperative morbidity due to brainstem nuclear and tract injury, complete resection
is not always the goal for brain stem cavernous malformations for those deep-seated
lesions.[[10]]
In our patient, a novel approach was done through the fourth ventricle and cavernoma
was excised without any injury to cortical fibers. Hence posterior medullary oblongata
lesions can be safely approached through the fourth ventricle after meticulous planning.
Conclusion
Incidence of medullary cavernous hemangiomas is rare. Surgery is the mainstay of treatment
in medullary cavernous hemangioma. A favorable outcome of surgery is achieved following,
meticulous preparation, investigations, and approach. Although symptoms of the disease
are not completely relived, quality of life, mortality and morbidity, and rehemorrhage
have significantly reduced.
