초록
Purpose: Congenital dermoid cysts develop during the fusion of the embryo when the ectodermal tissue gets trapped in the line of fusion. Dermoid cysts of the head are rare lesions comprised of epidermal and mesodermal elements. Furthermore, dermoid cysts in the occipital area are extremely rare. Only a few cases of dermoid cysts in the posterior scalp have been reported. Especially, A bilateral, synchronous presentation in this location has not been reported previously in the literature. Methods: All 5 cases had a gradually enlarging mass of the posterior aspect of the scalp. The cysts were mobile, noncompressible, and non-tender, without evidence of an associated sinus tract, skin dimpling, discoloration, or communication with adjacent structures. The CT scan displayed a hypodense cystic lesions about -87 to +24 HU (Housefield units, average +3.2 HU) with hypodense capsule and no postcontrast enhancement. All tumors were found just under the skin, and were well encapsulated, so they were completely removed the mass with adjacent periosteum. Results: On gross findings, all tumors were oval-or round-shaped, and when the cystic tumor was cut open it presented a greasy and caseous substance. Histologically, all specimens contain desquamated squamous epithelium and keratin in the lumen and are encapsulated and lined by keratinized stratified squamous epithelium. And, all cases of posterior mass are the presence of adnexal structures. Conclusion: Appropriate diagnosis requires not only an index of suspicion for this rare tumor a very careful history and search for skin changes. Especially, CT can reveal the exact location of the cyst, its relationship with the adjacent structures. We think that occipital dermoids divide into superficial and deep type. In our cases, because they did not have intra-cranial involvement or fistula formation, they are superficial type. This report describes the clinical and operative aspects of the superficial dermoid cysts and provides a review of the literatures.
