Immunohistochemical Study on Keratin Expression in Certain Cutaneous Epithelial Neoplasms; Basal Cell Carcinoma, Pilomatricoma, and Seborrheic Keratosis

Cytokeratin 10‐negative nested pattern enables sure distinction of clonal seborrheic keratosis from pagetoid Bowen's disease

“…A number of studies compared immunohistochemical stainings in SK and/or squamous cell carcinoma 10–18 . Puizina‐Ivić et al investigated bcl‐2 expression in squamous cell carcinoma and SK 14 and found that squamous cell carcinomas failed to express bcl‐2 while seborrheic keratoses expressed bcl‐2 in areas of basaloid proliferation.…”

“…The clonal pattern of SK is quite similar to the nested pattern of pagetoid SCCIS and both have been included under the heading of the ‘Borst‐Jadassohn phenomenon’ in the past 3,8,9 . Only few studies are available that have systematically studied morphological features and immunohistochemical markers in SK and Bowen's disease and very few of them addressed specifically clonal SK and pagetoid SCCIS 10–18 . We attempted to reassess histopathologic criteria for differentiation between both conditions and to compare them with selected immunohistochemical markers to identify reliable criteria for distinction.…”

Basal cell carcinoma: biology, morphology and clinical implications

“…7,8,37, 59 The cells of origin are held to be pluripotent progenitor epithelia in adults or epithelial germ cells in the case of those neoplasms arising in childhood (ie linear basal cell nevi). BCCs manifest a keratin profile similar to that of the lower part of the hair follicle 60 and that is therefore distinct from that of the adjacent epidermal basal layer epithelia. 60 In particular, and held to reflect their derivation from basaloid epithelia, BCCs express keratins type 5, 6 61 and 14 62 and also alpha 2 and beta 1 integrins 63 in a fashion that does not correlate well to tumor subtype.…”

“…BCCs manifest a keratin profile similar to that of the lower part of the hair follicle 60 and that is therefore distinct from that of the adjacent epidermal basal layer epithelia. 60 In particular, and held to reflect their derivation from basaloid epithelia, BCCs express keratins type 5, 6 61 and 14 62 and also alpha 2 and beta 1 integrins 63 in a fashion that does not correlate well to tumor subtype. The expression of CD10 supports deriva- Figure 16 Recurrent BCC: histomorphology.…”

Pilomatricoma can differentiate not only towards hair matrix and hair cortex, but also follicular infundibulum, outer root sheath and hair bulge

“…Ultrastructural and immunohistochemical study using anti‐hair keratin antibodies showed that basophilic cells and shadow cells appear to correspond to the hair matrix cells and immature hair cortex cells (8,9). Recent immunohistochemical studies using human keratin showed the presence of human hair basic keratin (hHb) 1 (10) and hHb5 (1) in transitional cells in pilomatricoma, suggesting that pilomatricoma differentiates towards the hair cortex.…”