Spectrum of squamous epithelial-lined cysts of the ovary (SECO): a case report of a mature teratoma of ovary masquerading as an epidermoid cyst (EC)

Aims To provide a differential diagnosis/histogenesis of squa-mous epithelial-lined cysts of the ovary (SECO). Methods A case of a 42-year-old with a history of ovarian cystec-tomy for strumal carcinoid, presenting with a squamous epithelial-lined cyst in an ipsilateral oophorectomy and confirmed as residual teratoma, was reviewed. A literature search was also conducted. Results Oophorectomy showed a keratin-filled cyst lined by mature stratified squamous epithelium with no skin adnexae or other overt tissue elements and resembling epidermoid cyst (EC). The entire lesion was processed and a single, small focus of smooth muscle identified in the cyst wall. Discussion EC is included in the WHO classification under monodermal teratomas, although its histogenesis is still controver-sial. 1 Some authors have shown that many EC reflect inadequately sampled teratomas or metaplasia in Brenner tumours and endome-triosis, and suggest pure EC probably comprise 2 Other possibilities include metaplasia in surface epithelial tumours, epithelial inclusion cysts, rete ovarii or hilar mesonephric tubules, while skin implantation during previous surgery has also been suggested. 1 As teratoma and EC may have different clinical follow-up, accurate diagnosis is important. 1 Our case highlights the importance of correlation with previous pathology and complete submission of the lesion to identify less prominent teratomatous components.