Congenital Giant Keratinous Cyst Mimicking Lipoma: Case Report and Review

Abstract

Epidermal cysts represent the most common cutaneous cysts. They arise following a localized inflammation of the hair follicle and occasionally after the implantation of the epithelium, following a trauma or surgery. Conventional epidermal cysts are about 5 cm in diameter; however, rare reports of cysts more than 5 cm are reported in the literature and are referred as "Giant epidermal cysts." Epidermal cysts although common, can mimic other common benign lesions in the head and neck area. A thorough clinico-pathologic investigation is needed to diagnose these cutaneous lesions as they differ in their biologic behavior, treatment, and prognosis. We report a case of a giant epidermoid cyst in the scalp area of a young female patient which mimicked lipoma on clinical, as well as cyotological examination. We also present a brief review of epidermal cysts, their histopathological differential diagnosis, and their malignant transformation.

Keywords: Giant epidermal cyst; histopathology; keratinous cyst; scalp.

Figure 1

Large pear-shaped swelling on the scalp

Figure 2

Lesion excised in toto

Figure 3

Extravasated muddy paste on grossing

Figure 4

Scanner view showing cyst lumen

Figure 5

Keratin flecks and squamoid cells

Figure 6

Keratin granuloma