Cerebellar metastatic brain cancer

Introduction

The brain is a common metastatic site for a variety of primary cancers. The majority of metastatic brain cancers occur in the supratentorial space, but approximately 10% to 20% metastasize to the posterior fossa. ^, ^, Cerebellar metastases, unlike most of their supratentorial counterparts, are associated with poorer survival, more distal recurrence, and higher risk of leptomeningeal disease. ^, ^, Moreover, tumors in the posterior fossa can cause significant symptoms out of proportion to their size, in which lesions can cause obstructive hydrocephalus, brainstem compression, and herniation with acute neurologic decline faster than similar sized supratentorial lesions. ^, In this chapter, we present a case of a patient with a cerebellar metastasis.

Example case

Chief complaint: headaches and lethargy

History of present illness

A 78-year-old, right-handed woman with a history of hypertension presented with headaches and lethargy. Over the past 2 weeks, she complained of progressive bifrontal headaches and lethargy in which she sleeps more than she typically does. She denies any nausea or vomiting ( Fig. 40.1 ).

Medications : Lisinopril.
Allergies : No known drug allergies.
Past medical and surgical history : Hypertension, negative breast biopsy 20 years prior.
Family history : No history of intracranial malignancies.
Social history: Retired school teacher, 30 pack per year smoking history, and occasional alcohol.
Physical examination : Awake, alert, oriented to person, place, and time; Cranial nerves II to XII intact; No drift, moves all extremities with full strength; Cerebellar: right > left finger-to-nose dysmetria.
Computed tomography chest/abdomen/pelvis : Enlarged mediastinal lymph nodes.

	Omar Arnaout, MD, Brigham and Women’s Hospital, Boston, MA, United States	Fernando Hakim, MD, Diego Gomez, MD, Hospital Universitario Fundacion Santafe de Bogota, Bogota, Colombia	Fredric B. Meyer, MD, Mayo Clinic, Rochester, MN, United States	Claudio Gustavo Yampolsky, MD, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
Preoperative
Additional tests requested	Chest, abdomen, pelvis CT	Oncology evaluation Thoracic surgery evaluation	Mediastinal lymph node biopsy evaluation Oncology evaluation	PET Oncology evaluation Mammogram
Surgical approach selected	Right suboccipital keyhole craniotomy	Midline suboccipital craniotomy	Midline suboccipital craniotomy	Midline suboccipital craniotomy
Anatomic corridor	Right infratentorial supracerebellar	Right transcerebellar hemisphere	Right transvermian	Right infratentorial supracerebellar
Goal of surgery	Gross total resection, relief of mass effect	Gross total resection, diagnosis, avoid obstructive hydrocephalus	Gross total resection, avoid obstructive hydrocephalus	Total resection without affecting function
Perioperative
Positioning	Right three-quarters prone	Prone Concorde	Prone	Prone Concorde
Surgical equipment	Surgical navigation Surgical microscope	Surgical navigation Surgical microscope Ultrasonic aspirator	Surgical navigation Surgical microscope	Surgical navigation Surgical microscope
Medications	Steroids	Steroids Mannitol	Steroids	Steroids
Anatomic considerations	Transverse sinus, bridging veins, tentorium	Vermis, occipital and transverse sinuses	Torcula and transverse sinus	Transverse sinus, tentorium, cerebellum, PCA, SCA, precentral vein
Complications feared with approach chosen	Cerebellar herniation, cerebellar dysfunction, pain	Truncal ataxia with vermian injury, obstructive hydrocephalus	Injury to venous sinuses	Air embolism, retraction of cerebellar peduncles
Intraoperative
Anesthesia	General	General	General	General
Skin incision	Paramedian linear from above sinus to above bottom of hairline	Midline linear	Midline linear from inion to C2	Midline linear from inion to C2
Bone opening	Right suboccipital	Right suboccipital over lesion	Midline suboccipital	Midline suboccipital
Brain exposure	Right cerebellar hemisphere	Right cerebellar hemisphere over lesion	Right cerebellar hemisphere over lesion	Bilateral cerebellar hemispheres
Method of resection	Linear incision, subperiosteal dissection, acorn drill bit to make suboccipital craniectomy with inferior aspect of transverse sinus exposed, V-shaped dural opening based on transverse sinus, gentle retraction on superior cerebellar surface to allow egress of CSF, sacrifice small bridging veins along superior cerebellar surface, microsurgical dissection until quadrigeminal cistern reached, allow more egress of CSF to avoid retraction, corticectomy along superior cerebellar surface until tumor identified, perilesional dissection with central debulking if necessary, inspect for residual tumor, watertight dural closure, cranioplasty with bone cement	Midline muscle dissection, right suboccipital craniotomy below transverse sinus based on navigation, Y-shaped dural opening, coagulate cerebellar surface, navigation-guided white matter dissection, dissect and remove lesion en bloc until gliotic plane seen, occipital burr hole and ETV if edema seen, watertight dural closure	Midline muscle dissection, craniotomy up to torcula and transverse sinus on side of tumor, dura opened in Y-shaped pattern, drain CSF from cisterna magna to provide relaxation, work along top of vermis to identify entry point, 1-cm vertical incision, tumor entered and debulked, infold the capsule, inspect for retained capsule, watertight dural closure	Linear incision, suboccipital craniotomy exposing inferior border of transverse sinus and 4 cm to the right and 2 cm to the left, V-shaped dural opening based on transverse sinus, expose cisterna magna, open cisterna magna and release CSF to allow cerebellar relaxation, create working space between tentorium and superior cerebellar surface with minimal retraction, minimal corticectomy over tumor, gross total en bloc and supramarginal resection of tumor
Complication avoidance	Open cisterns to allow brain relaxation, avoid retraction, perilesional dissection	Craniotomy over tumor below sinus, en bloc resection, ETV if edema seen	Large craniotomy up to sinuses, dissect above vermis, small opening, internal debulking	Drain CSF from cisterna magna, small corticectomy, en bloc resection
Postoperative
Admission	ICU	ICU	ICU	ICU
Postoperative complications feared	Cerebral edema, venous infarction, venous sinus thrombosis, stroke, hydrocephalus, CSF leak	Cerebral edema, hydrocephalus	Wound healing	CSF leak, swelling, nausea, vomiting, ataxia, headaches, nystagmus
Follow-up testing	MRI within 48 hours after surgery	CT within 72 hours after surgery	MRI within 24 hours after surgery	MRI within 48 hours after surgery
Follow-up visits	7–10 days after surgery	7 days after surgery	6 weeks after surgery with neurosurgery 2 weeks after surgery with oncology and radiation oncology	7 days after surgery with oncology and radiation oncology
Adjuvant therapies recommended	Consultation with oncology and radiation oncology	SRS to tumor cavity Chemotherapy per oncology	Radiation per radiation oncology	Radiation per radiation oncology Chemotherapy per oncology