A case report of hidroacanthoma simplex with an immunohistochemical study of cytokeratins

Abstract

Dear Sir,The origin of hidroacanthoma simplex (HS) is not yet clear. We report a case of HS in which the expression of cytokeratin (CK) was studied immunohistochemically using seven antikeratin antibodies. CK expression in HS has not been studied in detail before.HS, which was first described by Smith and Coburn, 1 is confined to the epidermis, and is recognized as intraepidermal eccrine poroma. An electron microscope study 2 found that tumor cells are identical to the outer layer of the intraepidermal eccrine duct. CK is a useful marker for investigating the origin of epithelial tumors. 3 Monospecific antikeratin antibodies may make it possible to clarify the origin and the differentiation of epithelial tumors. Histopathologically, HS arises from the lower portion of the epidermis, and extends downward into the dermis.The patient in this case was a 41-year-old woman. HS was located on her buttock. A sample was surgically excised, and the excised specimen was cut into sections of 4 µ m thickness, fixed in formalin, and embedded in paraffin. The sections were stained with hematoxylin and eosin for histopathologic examination. The antikeratin antibodies used here were 34 β B4 (Immunohistochemical procedures were performed using the labeled streptoavidin-biotin method, as reported previously. 8 Hematoxylin and eosin sections showed tumor nests with small basaloid cells in the epidermis. The border between the epidermis and the tumor was well defined.Cytokeratin expression in the normal epidermal eccrine sweat gland was investigated in previous reports. 9,10 The same staining patterns were observed in normal eccrine ducts in the sample. In HS, CK1 (Fig. 1) and CK10 were not present in the tumor cells. CK8 and 18 were also absent from the tumor cells. The tumor cells were positive for CK14, and strongly positive for CK17 (Fig. 2). CK19 was not found in the tumor cells.A previous immunohistochemical study 11 of cytokeratins in HS showed a negative reaction for 35 β H11 (CK8) and 35 β E12 (CK1, 5, 10 and 11). Our study clearly showed the presence in HS of CK14 and 17, and the absence in HS of CK1, 10 and 19. In the outer and inner cells of the acrosyringium, CK1 and 10 were present, and CK14 and 17 were absent. CK19 was present in the inner cells of the acrosyringium and intradermal ducts (Table 1). Our immunohistochemical study therefore shows that CK expression in HS has a different immunophenotype (characteristic) from that in acrosyringial cells. The presence of CK17 in HS implies that the tumor cells are in a hyperproliferative state, and the presence of CK14 Figure 1 The suprabasal layers in the epidermis are positive for CK1, but CK1 was not present in tumor cells (immunohistochemical stain, ×100)

Eccrine spiradenoma: co‐expression of cytokeratin and smooth muscle actin suggesting differentiation toward myoepithelial cells

“…CK 14 was positive for the basal cells in tumour nests. CK 17, expressed exclusively in myoepithelial cells in the secretory portions of the normal sweat gland, as reported previously 6,7 . Interestingly, CK 17 was detected in the tumour cells (fig.…”

“…The antikeratin and anti‐SMA antibodies in this study were as follows: 34 β4 (CK1) 2 , LP5K (CK7) 3 , LP3K (CK8) 3 , LHP1 (CK10) 2 , LL002 (CK14) 2 , LHK15 (CK15) 4 , LL025 (CK16) 2 , E3 (CK17) 2 , DC10 (CK18) 2 , b170 (CK19) 5 and 1A4 (SMA). Immunohistochemical study was performed based on the labelled streptoavidin‐biotin method (LSAB, Dako, Carpinteria, CA, USA) described previously 6 …”

Epithelial keratin and filaggrin expression in seborrheic keratosis: evaluation based on histopathological classification

“…Therefore, the clonal type of SK not only expressed K14 but also K17, suggesting that these cells are not clonal in keratin expression. K17 was also detected in hidroacanthoma simplex with Borst–Jadassohn phenomenon …”

Hidroacanthoma simplex: dermoscopy and cryosurgery treatment

“…However, CK1, 10, and 19, which were absent in HS, were found in the ductal structure in eccrine poroma. 4 …”