RESUMEN
Introduction and importance: Epidermal cysts are the most common subcutaneous tumor typically observed on the scalp, face, neck, back, or trunk. Epidermal cysts conventionally range in size from 1 to 5 cm, with sizes greater than 5 cm rarely reported. Case presentation: Here, we present a case of a 58-year-old female housewife who presented to our surgery outpatient department (OPD) with a history of a mass in the left occipital region. The mass was first noticed 3 years back and was small and associated with mild itching. The mass progressively increased in size over the course of 3 years. Her present complaint was a painful mass associated with itching, headache, and pus discharge when compressed. The pain was relieved by taking medication. Clinical discussion: The epidermal cyst was confirmed on biopsy, and subsequent excision of the cyst was done under general anesthesia; the occipital bone was eroded by the inferior part of the cyst - reconstruction of scalp defect done by rotational scalp flap. Conclusion: Epidermal cysts, being a slow-growing benign tumor, can pose diagnostic difficulties, especially when located in the scalp area. In addition to that, when cranial bones and intracranial structures are affected by the cyst, they can even lead to complications and interventional difficulties.