Eccrine differentiation in basal cell carcinoma

Basal Cell Carcinoma Arises from Interfollicular Layer of Epidermis

Background

BCC is currently the most common type of skin cancer in humans. Although having a low-grade malignancy and metastatic potential, BCC is locally aggressive and destructive. Despite numerous studies, the origin of BCC, whether arising from the follicular or interfollicular layer, remains controversial.

Objectives

This study aims to evaluate whether BCC arises from the follicular or interfollicular layer by using immunohistochemical staining.

Methods

Twenty-three specimens of superficial and nodular BCC at its very early stage were examined. The samples were immunohistochemically stained using BerEP4 antibody. The stained specimens were then examined and scored by 2 independent observers.

Results

BerEP4 was found to be strongly positive in all BCC lesions, including a very early lesions budding off the basal layer of the epidermis.

Conclusion

This study confirmed that the origin site of BCC is basal layer of epidermis. This finding suggests that BCC arises from the interfollicular epidermis.

Penile basal cell carcinoma with eccrine differentiation

Basal cell carcinoma (BCC) is rare on the penis. There have been only 17 cases of penile BCC reported in the literature. Eccrine differentiation may not be uncommon in BCC but has not been reported in penile BCC. We report here a 75-year-old man with multiple penile BCC with histological features of eccrine differentiation. A brief review of the literature is included. Basal cell carcinoma (BCC) is the most commonly diagnosed malignant skin tumour; it probably originates from pluripotential cells in the epidermis or hair follicle. More than 90% of BCCs are located on the head or neck, and its occurrence on the penis is rare. Seventeen cases of penile BCC have been reported in the literature.

The altered expression of alpha-smooth muscle actin in basal cell epithelioma and its surrounding stroma: with special reference to proliferating cell nuclear antigen expression and adenoid differentiation

Altered expression of alpha-smooth muscle actin (alpha-SMA) is known to indicate the morphological, tumorigenic and immunological changes occurring in tumour and stromal cells. The purpose of this study was to analyse the dynamics of alpha-SMA expression in human basal cell epithelioma (BCE) cells and their surrounding stromal cells, in the process of differentiation towards cutaneous appendages such as hair, sebaceous, apocrine and eccrine glands. Using anti-alpha-SMA specific monoclonal antibody (MAb), 17 of 36 BCEs (47%) were shown to express alpha-SMA, despite the usual absence of alpha-SMA in all eukaryotic cells except muscle cells. Solid, adenoid and sclerosing types of BCE expressed alpha-SMA more frequently, and in greater amount, than cystic, keratotic and superficial types. Furthermore, the expression of alpha-SMA in BCE cells significantly paralleled the expression of proliferating cell nuclear antigen (PCNA) in these cells. Thus, the altered expression of alpha-SMA may reflect the growing properties of BCE cells under the specific cellular regulations for differentiation. In addition, we have found anti-alpha-SMA MAb-positive fibroblasts with smooth muscle differentiation (myofibroblasts) in desmoplastic stroma surrounding BCE nests in 13 of 36 cases (36%). Coincidental expression of alpha-SMA in both BCE cells and stromal cells was found in nine of the 13 cases (69%), indicating the possibility of the induction of myofibroblastic stromal changes in surrounding tissues by cytokines secreted from BCE cells [e.g. basic fibroblast growth factor (bFGF)-like factor].