Basal cell carcinoma: from host response and polymorphic variants to tumour suppressor genes

The molecular factors and events that characterize susceptibility and outcome in cutaneous basal cell carcinoma (BCC) have been the focus of much research interest. As a result, we are beginning to understand the complex relationships between exposure to ultraviolet radiation (UVR), host response and the resulting damage to key genes that characterize these tumours. In this review, we will focus on genetic factors that influence susceptibility and outcome. While the search for susceptibility genes has generally resulted in the identification of low penetrance allelic variants, studies on modifier genes influencing outcome variables such as tumour number, age of onset and tumour subtype have identified factors with higher potential impact. Here we will briefly describe some recent work on the genetic basis of the immune response to UVR, the effect of UVR on the generation of reactive oxygen species and their detoxification, and the role of onco- and tumour suppressor genes. Areas for further research are highlighted, together with a consideration of possible applications in clinical practice.     

Basal cell carcinoma with tumor epithelial and stromal giant cells: a variant of pleomorphic basal cell carcinoma.

A case of basal cell carcinoma with giant cells of the central epithelial and surrounding stromal components is presented. The lesion was an 8-mm dome-shaped papule on the ear of a 66-year-old man. The giant cells of the epithelial component shared the immunophenotype of the more typical cells of the basal cell carcinoma (keratin, smooth muscle actin, and bcl-2 positive), whereas the stromal giant cells were positive only for bcl-2. This case represents a peculiar variant of pleomorphic basal cell carcinoma, the significance of which is unknown.     

Basal cell carcinomas with unusual histologic patterns

Uncommon histologic variants of basal cell carcinoma (BCC) can present a diagnostic challenge. In this case series, we describe 3 patients with unusual BCCs encountered in a dermatologic surgical unit over a 1-year period from September 2003 to September 2004. The formalin-fixed, paraffin-embedded histologic specimens were initially examined microscopically after staining with hematoxylin and eosin. Additional stains, including diastase periodic acid-Schiff, colloidal iron, carcinoembryonic antigen, and cytokeratin-20, were subsequently performed as appropriate. Of the 3 lesions, one exhibited apocrine differentiation and two demonstrated a trabecular growth pattern. Although BCCs demonstrating apocrine differentiation have previously been described, a trabecular growth pattern, to our knowledge, has not been previously reported for BCC.     

Basal cell carcinoma with matrical differentiation: a case study with analysis of beta-catenin

Matrical differentiation in basal cell carcinoma (BCC) is rare. Only nine cases have been described that showed typical diagnostic features of BCC, in addition to shadow cells indicating hair-matrix differentiation. These cases often present a diagnostic challenge due to confusion with pilomatrixoma or pilomatrix carcinoma. We present a case of BCC with matrical differentiation in a 78-year-old man. Immunohistochemical and molecular methods are used to differentiate this lesion from benign or malignant forms of pilomatrixoma. differentiation: a case study with analysis of beta-catenin.     

Basal cell carcinoma: treatment with imiquimod

BACKGROUND: Basal cell carcinoma (BCC) is the most common cutaneous malignancy. There are various approaches to its treatment, but imiquimod, the immune response modifier, offers a topical, noninvasive, nonsurgical therapeutic option. METHODS: We present our experience of the treatment of 96 patients with BCCs during the period March 2002 to February 2004 at the Dermatology Department, Hospital Clínico S. Cecilio, Granada, Spain. One hundred and forty-one tumors (nodular, superficial, and pearly/ulcerated clinical types) were treated with imiquimod. RESULTS: The clinical cure rate at 12 months was 80-85%. CONCLUSION: Our experience indicates that imiquimod is a reasonable option for the treatment of BCC. It is low cost, can be delivered via ambulatory care, and has tolerable side-effects.     

Basal cell carcinoma with ossification

Background: Osteoma cutis, the presence of lamellar bone in the skin, is relatively common. This process is divided into two categories: primary osteoma cutis and secondary osteoma cutis. Objective: The purpose of this study was to describe the clinical and histopathologic features of patients in whom lamellar bone developed in cutaneous basal cell carcinoma. Methods: We evaluated the features of five cases of osteoma cutis associated with basal cell carcinoma and obtained detailed clinical information from those patients. Results: All five patients had significant underlying medical conditions, including two patients who were receiving interferon alfa-2b therapy. Three patients had been previously treated with electrodesiccation and curettage. The amount of sun exposure experienced by these patients varied. Histologically, the basal cell carcinomas were of the nodular or micronodular variety. Bone was found both in the stroma and intratumorally. Conclusion: The presence of bone within basal cell carcinomas is not uncommon and may be more prevalent in patients with an underlying medical disorder. (J Am Acad Dermatol 1998;38:906-10.)     

Letter: Basal cell carcinoma with vascular invasion

Non-melanoma skin cancer (NMSC) is the most common cancer in humans. Basal cell carcinoma accounts for 75 percent to 80 percent of NMSC. We report a primary cutaneous BCC on the upper chest in which vascular invasion was demonstrated by histopathology and the unique application of dual immunohistochemistry.     

Basal cell carcinoma overlying a dermatofibroma

The epidermis over a dermatofibroma may show changes that range from simple hyperplasia to the proliferation of basaloid cells, which can become morphologically indistinguishable from basal cell carcinoma. The existence of a true basal cell carcinoma overlying a dermatofibroma is infrequent. These basaloid proliferations have usually been considered to be the result of the inductive effect of the fibrohistiocytic proliferation of the dermatofibroma on the epithelial cells of the hair follicle; therefore, it would be a reactive phenomenon and not truly neoplastic. We describe a case of dermatofibroma that presented with a basaloid proliferation identical in appearance to a basal cell carcinoma on the overlying epidermis.     

Basal cell carcinoma with follicular differentiation

A distinctive form of basal cell carcinoma with follicular differentiation was studied in 15 biopsy specimens. The neoplasms differ from other variants of basal cell carcinoma by being situated on the face only, being small and well circumscribed, and having signs of follicular differentiation, namely, numerous tiny infundibular cyst-like structures and aggregations of neoplastic cells that resemble hair follicles in telogen. The diagnostic features of basal cell carcinomas with follicular differentiation are enumerated and illustrated.     

Basal cell carcinoma with massive ossification

We report a case of basal cell carcinoma with massive ossification in a 66-year-old white man. Ossification in various benign and malignant neoplasms have been reported including basal cell carcinomas, in which ossifications are seen in small foci or peripheral rim of the tumor. However, in our case, massive ossification is seen throughout the tumor, and only small areas of the periphery of the tumor show diagnostic histology. Therefore, this case might have presented a diagnostic difficulty or been misdiagnosed as an osteoma cutis if a smaller incisional or punch biopsy had been performed. The phenomenon of bone formation itself is not specific for any diagnostic entity, and therefore an underlying lesion should be carefully sought in case of secondary ossification.     

Basal cell carcinoma with monster cells

A case of basal cell carcinoma with "monster cells" is reported. Clinically, the lesion presented as a red nodule on the forearm of a 58-year-old male. The histologic picture was striking, with large, "monstrous" nuclei scattered throughout a well defined nodule. Basal cell carcinoma with monster cells appears to represent a histologic variant of nodular basal cell carcinoma. The prognostic significance of the monster cells remains to be established.