Cutaneous dermoid cyst: Cytokeratin and filaggrin expression suggesting differentiation towards follicular infundibulum and mature sebaceous gland

Abstract

Abstract. We experienced two cases of cutaneous dermoid cysts (DC). To elucidate the histogenesis of DC, we have studied cytokeratin (CK) expression in DC using ten different anti-keratin antibodies against CK1,7,8,10,14, 15, 16, 17, 18 and 19, antibody. In the cyst wall of DC, CK1 and 10 were expressed in suprabasal layer, and CK14 was limited to the basal layer. In sebaceous gland-like structures, CK14 was detected in sebaceous acinus, and CK17 was detected in sebaceous duct. The other CKs were not detected. Filaggrin was intensely detected in the granular layer in the cyst wall of DC. CK expression profile of DC was similar to follicular infundibulum and sebaceous gland. These results suggested that DC differentiates towards follicular infundibulum and mature sebaceous gland. IntroductionCutaneous dermoid cysts result from the sequestration of cutaneous tissue along lines of embryonic fusion (1). DC in the periorbital area, midline of the neck, nasal root, forehead, mastoid area and the scalp have been reported (2). DCs of the auricle are very rare (3). The histogenesis of DC still remains unclear.CK is an essential marker to evaluate the origin of epithelial tumors (4). Besides CK, filament aggregating protein (filaggrin), a histidine-rich phosphorylated basic protein of major constituents of keratohyaline granules, is a marker of terminal differentiation of epidermis (5). No immunohistochemical study of CK and filaggrin in DC has been reported.To elucidate the histogenesis of DC, we studied CK and filaggrin expression in DC using ten different anti-keratin antibodies against CK1,7,8,10,14, 15, 16, 17, 18 and 19, and anti-filaggrin antibody. Materials and methodsThe patient, a 48-year-old male had DC located on the left postauriclar area from at birth. The other patient, a 31-yearold female developed DC on the right postauriclar area ten years ago. The lesions were surgically excised. Each specimen was formalin-fixed, paraffin-embedded, stained with hematoxylin and eosin, and serially-cut sections were used for the immunohistochemical study. The anti-keratin antibodies used were as follows: 34ßB4 (CK1) (6), LHP1 (CK10) (7), LL002 (CK14) (7), LHK15 (CK15) (8), LL025 (CK16) (7), E3 (CK17) (7), 5D3 (CK18) (7) and b170 (CK19) (9) (all from Novocastra Laboratories Ltd., Newcastle-upon-Tyne, UK).The immunohistochemical study was carried out with the labeled streptoavidin-biotin method (LSAB, Dako, Carpenteria, CA, USA) was performed as previous study (10). Normal skin from the auricle served as controls. ResultsHematoxylin and eosin staining. Histopathological findings of the cases were similar. The cyst wall of DC was located in the deep dermis. Cyst wall was partly ruptured, resulting in the fibrosis with vellus hairs. The cyst wall was formed with keratinizing epithelium in granular layers. The keratinizing epithelium partly projected into the lumen-like crenulation. Thick laminated corneocytes were observed. In the vicinity of the cyst wall, sebaceous gland-like structure was observed (Fig. 1).Immunohistochem...

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“…Dermoid cyst: The cyst wall and associated sebaceous gland‐like structures of dermoid cyst differentiate to follicular infundibulum (K14, K1/K10) and sebaceous glands (K14, K17), respectively, based on keratin expression (103).…”

A Keratocyst in the Buccal Mucosa with the Features of Keratocystic Odontogenic Tumor

“…KCOT can be differentiated from cutaneous cystic lesions such as trichilemmal cyst and steatocystoma by its catagen pattern and the presence of pilosebaceous units, respectively [ 12 ], even if these develop in the buccal mucosa; however, cutaneous keratocysts resembling steatocystoma and lacking pilosebaceous units are quite difficult to differentiate from KCOT, since the corrugated anagen-like lining of these keratocysts is quite similar to that of KCOT [ 13 ]. Furthermore, the lining epithelium of steatocystoma, not of sebaceous cells, shows a similar pattern of cytokeratin expression to KCOT [ 7 , 14 ]. Cutaneous keratocysts rarely occur because once a true follicular cyst develops from the isthmus of a hair follicle, its lining possibly adopts a catagen pattern [ 13 ]; however, the ectopic development of a cutaneous keratocyst in the buccal mucosa cannot be completely excluded.…”

Pediatric dermatohistopathology – histopathology of skin diseases in newborns and infants

“…The cyst's lumen is unilocular and lined by stratified, orthokeratotic epithelium with stratum granulosum (Figure a). Recent studies have shown that dermoid cysts have a characteristic cytokeratin profile, which suggests that they originate from the follicular infundibulum . However, lesions also frequently show “sawtooth” cornification, as seen in sebaceous gland ducts and steatocystoma (Figure b).…”