Lamella, cornoid

Histologic phenomenon with columnar narrow cone of parakeratosis extending through the orthokeratotic horny material. The epithelium at these sites is slightly sunken, focally lacking the stratum corneum.

Keratinocytes below the corneal lamella are vacuolated, isolated single cell necroses are found; the corneal lamella is characteristic for diseases of the porokeratosis group and was primarily described by the Italian dermatologist Vittorio Mibelli.

1. Ito M et al (1991) Morphogenesis of the cornoid lamella: histochemical, immunohistochemical, and ultrastructural study of porokeratosis. J Cutan Pathol 18: 247-256
2. Leung CS et al (1998) Porokeratotic eccrine ostial and dermal duct naevus with dermatomal trunk involvement: literature review and report on the efficacy of laser treatment. Br J Dermatol 138: 684-688.
3. Sharquie KE, Al-Baghdady BA (2003) Solar facial porokeratosis. J Dermatol 30: 216-221
4. Shen CS et al (2002) Premature apoptosis of keratinocytes and the dysregulation of keratinization in porokeratosis. Br J Dermatol 147: 498-502