Immunohistochemical staining for the differentiation of subungual keratoacanthoma from subungual squamous cell carcinoma

Abstract

SUKAs do not express Ki67 strongly whereas some subungual SCCs do. Thus we conclude that immunohistochemistry for p53 and Ki67 may help distinguish between a subungual SCC and a SUKA.

Sonography of the Nail

“…In contrast to other types of keratoacanthomas (out of the ungual region), this type of tumor may not show spontaneous regression, sometimes grows progressively, and can clinically mimic a digital squamous cell carcinoma (SCC). On sonography, a well circumscribed solid-cystic mass that shows a mixed echogenicity pattern (anechoic center and hypoechoic rim), with remodeling or erosion of the bony margins, as well as a posterior acoustic enhancement artifact has been described [ 6,[70][71][72] (Fig. 18.39 ).…”

Subungual squamous cell carcinoma

“…Although dyskeratotic cells were present on histology, given the age of our patient and strong p53 staining in the majority of basal cells,1 the favoured diagnosis was a well-differentiated subungual SCC (figure 2). Subsequent skin cancer multidisciplinary team discussion recommended amputation through the interphalangeal joint.…”

Cytokeratin 17 and Ki-67: Immunohistochemical markers for the differential diagnosis of keratoacanthoma and squamous cell carcinoma

“…Multiple studies have identified significant overexpression of Ki-67 in SCC compared with that in KA (6,7,21,23–26). Scola et al (6) suggested that a Ki-67 fraction of <20% may therefore be indicative of KA.…”

“…Therefore, multiple immunohistochemical markers have been investigated to overcome this limitation (5). Proliferation marker protein Ki-67 (Ki-67) is a cell cycle-regulating protein frequently studied in squamoproliferative lesions and the most useful marker among immunohistochemical markers (6,7). Cytokeratin (CK) 17 is a basal/myoepithelial cell-associated keratin protein that is expressed in the outer root sheath of wild-type hair follicles (8).…”