AOS Journal

Introduction

Epidermoid cysts are usually painless and slowly grow as domeshaped skin lesions that may have varying textures - from firm to fluctuant. These cysts are commonly found on the neck, trunk, face, scalp, and scrotum. They typically arise when pilosebaceous follicles rupture due to an obstruction of the sebaceous gland opening, leading to a surface comedo or punctum.[1] These conventional epidermoid cysts have an epithelial wall and can range in size from a few millimeters to five centimeters in diameter. Although rare, giant epidermoid cysts with a diameter of 5 cm or more have been reported.[2] In this case, we report a giant epidermoid cyst over the scalp in an elderly woman, which was successfully removed.

Case Report

An elderly woman, aged 72,was admitted to the neurosurgical ward with a complaint of a large swelling on her scalp that had been present for 50 years. She first noticed the swelling when she was 22 years old, and it was initially about 5 x 5 cm in size. However, it kept growing slowly, and over the last five years,it started increasing more rapidly towards the left side. The swelling also became ulcerated at the apex. The patient had also been experiencing neck pain for the last year, which radiated to her left shoulder, especially when standing. She also complained of a deformity in her neck that caused an abnormal forward bend. The swelling was so large that the patient was unable to sleep or lie down in a supine position. However, she had no associated complaints of fever, weight loss, or any other lumps in her body (Figure 1).

Figure 1: Clinical preoperative photograph showing a giant epidermoid cyst of the scalp.

During the inspection, a swelling in the bilateral parieto-occipital region of the scalp was observed. The swelling measured 26x24x12 cm and had a globular shape with a lobulated surface. It had clearly defined edges,was soft, painless, non-tender, cystic, and showed no signs of infection. There was no evidence of expansile or pulsatile pulsations, and no impulse was observed on coughing. The overlying skin had normal color with venous engorgement, but there were no signs of redness or edema. Additionally, there was ulceration on the apex of the swelling. The transillumination test was negative.thin walled, cystic fluid collection of size 26 x 24 x 12 cm seen arising from deep scalp layers of left parieto-occipital region, extending from midline posterior high parietal region up to posterior aspect of occipital bone abutting their outer cortices and with normal underlying bone with no intra-cranial extension of the lesion (Figure 2).

Figure 2 : Preoperative NCCT Head-Saggital cuts.

The patient was diagnosed with a large epidermoid cyst based on the findings. Lipoma and dermoid cyst were also considered as potential differential diagnoses. A preoperative Non-Contrast-CT scan of the skull was done to check for any bony or intracranial involvement. The scan revealed a large multiloculated, thin-walled, cystic fluid collection measuring 26 x 24 x 12 cm. The cyst was found in the deep scalp layers of the left parieto-occipital region and extended from the midline posterior high parietal region up to the posterior aspect of the occipital bone, abutting their outer cortices, with normal underlying bone with no intracranial extension of the lesion.On preoperative Magnetic Resonance Imaging (MRI), a large cystic lesion was detected in the scalp region between the parietal and occipital lobes. The lesion was well-defined, had multiple compartments, and measured around 26 cm × 24 cm × 12 cm. The cystic lesion did not affect the skull or brain. On T2-weighted images, the lesion appeared homogeneous with a high-intensity signal (Figure 3).

Figure 3 : T2 WI-Magnetic resonance image-Axial cuts.

Complete en mass excision of the lesion was carried out by an elliptical incision under general anesthesia and the wound was closed in layers, after adjustment of the flaps. An elliptical incision with a vertical extension lines was designed with consideration of redundant skin, and the dissection was extended from the subcutaneous layer to the subgaleal plane to expose the mass. Neovascularization was detected in the vicinity of the growth. Upon confirming that the mass was encapsulated, it was entirely removed. The mass had a weight of 3000 grams. Additionally, we excised the excess skin that had stretched to accommodate the mass and conducted primary closure. The wound healed without any problems or complications.The gross appearance of the mass showed that it had an outer membranous capsule with inner yellow and brown debris, and cut surface showing greyish white areas (Figure 4).

Figure 4 : Gross total excision of mass

The cystic lumen was filled with pultaceous fluid and showed degenerated and necrotic keratinaceous debris on histologic findings (Figure 5).

.Figure 5 : Histologic findings. There is an outer membranous capsule with inner degenerated and necrotic keratinaceous debris.

The postoperative period was uneventful and an excellent scar was noticed on follow-up (Figure. 6).