Disorders of keratinization

Ichthyoses—A Clinical and Pathological Spectrum from Heterogeneous Cornification Disorders to Inflammation

“…There are superficial and perivascular lymphocytic infiltrates with single neutrophils, which are also found in the stratum corneum. The papillary body is elongated and edematous, vessels are not dilated [7]. Immunohistochemically, staining for corneodesmosin is absent in the stratum corneum [23].…”

“…Histologically, there is compact orthohyperkeratosis, a slightly widened stratum granulosum, acanthosis, and papillomatosis of the epidermis. In the papillary body, the vessels appear dilated and spiraling, and lymphocytic infiltrates are scarce or mild (Figure 4) [7]. The ARCI forms are caused by different mutations.…”

“…Complementary histo-and immunohistochemical methods allow for, in part, a precise diagnosis, but at least a limitation of differential diagnoses, which can then be further clarified by targeted mutation analyses [6,7]. In the following, the dermatopathological diagnosis is presented on the basis of some frequent, but also rare syndromic and life-threatening ichthyoses, which can be performed quickly, easily, and economically on sample biopsies of the skin.…”

Porokeratotic lichen planus

“…However, the cornoid lamella is a nonspecific finding and may be found in solar keratosis, psoriasis vulgaris, dermatomyositis (Wong type), atypical keratosis lichenoides chronica (atypical Nekam's disease), some ichthyoses, verruca vulgaris, verrucous epidermal nevus, porokeratotic eccrine nevus, as well as squamous and basal cell carcinomas etc. [5]. Furthermore, interface dermatitis with basal cell vacuolization is seen rarely in porokeratosis as well, leading to a diagnostic dilemma and causing confusion in the pathologic diagnosis of porokeratosis.…”

“…In such situations, diseases like lichen planus and lupus erythematosus etc. should clearly be excluded [5][6][7].…”