Cerebellopontine angle epidermoid cyst: Case report and review of outcomes and embryological pathogenesis

• Posterior-auricular pain and tremor in a rare CPA epidermoid cyst case. • DWI-MRI identified epidermoid, resulting in retrosigmoid microsurgical resection. • Gross total resection resulted in full neurologic recovery with minimal morbidity. • Subtotal resection shows ≥7-fold higher recurrence; lifelong MRI surveillance recommended. • Dysregulated developmental transcription factors could play a role in ectodermal rest survival and cyst genesis. Cerebellopontine angle (CPA) epidermoid cysts are rare, benign lesions that remain diagnostically and surgically challenging. We present an illustrative case of a 53-year-old man with progressive unilateral hearing loss, headache, vertigo, tremor, and gait incoordination. MRI revealed a multiloculated, diffusion-restricting CPA mass. The patient underwent retrosigmoid microsurgical resection and gross total resection was achieved. Postoperative recovery was uncomplicated aside from transient gait imbalance. Histopathology confirmed an epidermoid cyst. A narrative review contextualizes this case within the literature. Complete resection offers the lowest recurrence rates while subtotal excision portends up to a seven-fold increase in recurrence. New cranial nerve deficits represent the most common complications. Long-term surveillance is essential because recurrences can present decades later. Pathogenetically, epidermoids arise from ectodermal rests sequestered during neural tube closure. Recent work may implicate dysregulated developmental transcription factors in maintaining an epidermal phenotype within neural tissue. Aberrant expression of such factors in dorsal ectoderm may hinder full neural differentiation, allowing cutaneous inclusions to persist and later form cysts. Early recognition via MRI, microsurgical technique balancing total removal with neurological safety, and follow-up are pivotal to optimizing outcomes and quality of life for patients with CPA epidermoid cysts.