Cytokeratin expression in steatocystoma multiplex

Cutaneous Adnexal Cysts Revisited: What We Know and What We Think We Know

Cutaneous cysts have been classified by dermatopathologists in many different ways. Here, we propose a novel classification of cutaneous adnexal cysts according to their origin in the folliculosebaceous unit and the sweat glands. By examining the lining of the cystic structure, its origin can be easily identified. Epidermal cysts have an epithelial wall containing a granular layer with lamellar keratinization, indicating an infundibular origin. Tricholemmal cysts have an undulating epithelial wall with no granular layer and a compact keratinization, showing an isthmic origin. In steatocystoma, dermoid cyst, and folliculosebaceous hamartoma, the epithelial lining shows a crenulated appearance which is seen in the sebaceous duct. Hidrocystoma shows the characteristic cuboidal epithelial lining of sweat glands with decapitation secretion in its apocrine forms. The hair matrix cyst wall is composed of basaloid cells maturing to squamoid cells, as seen in the normal hair matrix and shadow cells in the lumen. Metabolizing acquired dioxin-induced skin hamartoma (MADISH) is a cystic lesion with lamellar keratinization, and no sebaceous glands. The classification proposed here aims to simplify the complexity of cutaneous adnexal cysts, and to facilitate a better understanding of the origin of cystic lesions of the skin.

Unusual Eyelid Dermal Keratinous Cysts of Pilosebaceous Origin

PURPOSE

To describe 2 types of previously unrecognized dermal keratinous cysts of the eyelids-2 single sebaceous duct cysts derived from the glands of Zeis and 2 cases of multiple eruptive vellus hair cysts, both types associated with the pilosebaceous apparatus.

METHODS

Clinical records and paraffin sections subjected to hematoxylin and eosin and acid-fast staining were critically reviewed from each case, and additional sections were immunoreacted for cytokeratins (CKs) 7, 14, and 17.

RESULTS

Two patients had a slowly enlarging solitary sebaceous duct keratinous cyst at the eyelid margin where the glands of Zeis are located. The squamous cell lining displayed a corrugated squamous membrane manifesting an eosinophilic, refractile, surface cuticle. Either a sebaceous gland or a hair was proximate to the cyst. The squamous lining was CK7, CK14, and CK17. Two other patients developed over 2 and 10 years a different condition consisting of unilateral or bilateral clusters, respectively, of small papules of the upper eyelids. These were lined by keratinizing squamous epithelium without a cuticular membrane. Numerous small vellus hairs along with keratin in the lumens were discovered with acid-fast staining. The epithelium was also CK7, CK14, and CK17.

CONCLUSIONS

Histopathologic and immunohistochemical studies can separate these 2 disparate new eyelid entities from the more common keratinous epidermoid cyst of the surface epidermis or the upper hair follicle (CK7, CK14, and CK17). Simple local excision of the anterior lamella of the eyelid is appropriate for the sebaceous duct keratinous cysts of Zeis, but the multiple vellus hair cysts are comparatively refractory to treatment. Both superficial types of cysts are totally unrelated to the deeper Meibomian keratinous cyst, which is not associated with a hair structure and is situated in the tarsus rather than the dermis of the eyelids.

Eruptive vellus hair cysts: report of a new case with immunohistochemical study and literature review

Eruptive vellus hair cysts (EVHC) are rather uncommon lesions, of which 222 cases have been published in the literature. Their etiopathogenesis is poorly known. We report herein a new typical case of EVHC that was studied immunohistochemically. A 15-year-old male presented with a 4-year history of progressively developing small brown-gray papules on the trunk and extremities. Microscopically the lesions consisted of small epidermoid cysts containing vellus hairs. Immunohistochemically, the lesions expressed keratin 1/10, calretinin and p63 but no epithelial membrane antigen, filaggrin or androgen receptors. A review of the relevant literature shows that EVHC may be inherited or acquired and may be associated to other genodermatoses, namely sebocystomatosis. They could be due to hamartomatous follicular growth, to a trouble in infundibular keratinization leading to vellus hair follicle occlusion, or represent an example of acquired hamartoma. Although benign, this condition is difficult to treat.

Intratarsal keratinous cysts of the Meibomian gland: distinctive clinicopathologic and immunohistochemical features in 6 cases

PURPOSE

To describe 6 patients representing a new entity of Meibomian gland keratinous cysts.

DESIGN

Retrospective, interventional, clinicopathologic study.

METHODS

Review of clinical histories and findings, histopathologic evaluations, and immunohistochemical studies of the cysts' linings with monoclonal antibodies directed against cytokeratins and cell surface epithelial markers.

RESULTS

Six patients with an average age of 62.5 years had noninflamed, upper eyelid nodules fixed to the tarsus. Eyelid eversion revealed a white-yellow nodular bulge in 3 cases, a bluish coloration in 2 cases, and a translucent appearance in 1 case. The cysts were lined by undulating squamous epithelium possessing an inner eosinophilic cuticle that produced a peculiar refractile, strand-like intracavitary keratin. Immunostaining for cytokeratin 17 and carcinoembryonic antigen showed strongly positive results in the Meibomian gland cysts and, by comparison, negative results in cutaneous epidermal cysts. Multiple recurrences occurred after incomplete excisions.

CONCLUSIONS

After chalazia and sebaceous cell tumors, Meibomian gland keratinous cysts seem to be the third most common primary intratarsal lesion. Anterior fixation to the tarsus and posterior protrusion beneath the palpebral conjunctiva without inflammation suggest the diagnosis. Histopathologic and immunohistochemical evaluations can distinguish unequivocally the current entity from common epidermal cysts. The optimal treatment consists of an en bloc excision of the cyst with a tarsectomy, or else wide excision with intratarsal cautery of any remnants of the cellular lining.