Intracranial squamous cell carcinoma arising in a cerebellopontine angle epidermoid cyst

Abstract

Rationale:Most of the intracranial epidermoid cysts are benign, but malignant lesions are occasionally reported. These lesions appear as squamous cell carcinoma and carry a dismal prognosis. Here, we report a case of a primary intracranial squamous cell carcinoma arising in a cerebellopontine epidermoid cyst. The relevant literatures were also reviewed.Patient concerns:A 53-year-old woman presented with dizziness and diplopia 9 months in duration. Magnetic resonance imaging revealed an epidermoid cyst in the left cerebellopontine angle and prepontine region with a focal enhancing lesion on T1-weighted gadolinium-enhanced images.Diagnoses:Histopathologic diagnosis revealed squamous cell carcinoma on a background of epidermoid cyst. Imaging studies excluded metastases.Interventions:The tumor was removed subtotally through a lateral suboccipital approach. The patient received intensity modulated radiation therapy (6720 cGy total) postoperatively.Outcomes:The patient was free from recurrence of the tumor until 3 years after surgery, at which point she was lost to follow-up. The patient died 4 years after the surgery.Lessons:The epidermoid cyst may occasionally become malignant. Finding an area of enhancement through preoperative magnetic resonance imaging can help to make a correct diagnosis. Based on the review of previous reports, surgical removal followed by radiotherapy shows the best result to treat malignant epidermoid cysts.

Physiopathological Aspects of Sellar Epidermoid Cyst Determining Endocrine Disturbances: A Case Report

“…6 The pattern of embryological formation of the hypothalamic-pituitary-axis plays a major role in its propensity in the development of sellar ECs. 3,4,[12][13][14][15][16] Neurulation can be divided broadly into primary and secondary phases. In primary neurulation, which occurs throughout the future brain, the neural tube is formed by neural folding.…”

“…Unlike dermoid cysts, ECs often occur laterally, without a preference for midline sites. 3,4,[12][13][14][15][16][17][18] Intracranial ECs account for only 1% of all intracranial tumors, if suprasellar examples are excluded. The cerebellopontine angle and parapontine regions are the most common intracranial site for ECs.…”

“…The cerebellopontine angle and parapontine regions are the most common intracranial site for ECs. 2,3,8,11,[15][16][17] Epithelial rests may be transplanted to regions such cerebellopontine angle by the lateral migrating otic capsule or developing neurovasculature. Intraspinal lesions are less common.…”

“…Rarely, ECs are located in the cranial diploe of the middle ear region or frontal bone, where they present as a lytic defect. 2,3,7,8,11,[15][16][17][18] The authors reported a female patient with clinical complaint of amenorrhea due to a sellar EC. Symptoms associated to sellar EC can be related to a slow growing mass effect, and include focal neurologic deficits or nonlocalizing signs such as headache, visual alterations, and pituitary dysfunction.…”

“…1,4,6,10,15,17,19,20 On gross, sellar ECs are a pale-gray, uniloculated, translucent lesion, which can measure from a few millimeters to over 4 cm in diameter. 1,4,6,9,15,16,21,22 At microscopy, ECs are covered by a mature keratinizing squamous epithelium, and the lumen is occupied by lamellae of keratin. No evidence of atypias can be found and the wall is constituted by connective tissue.…”