Annular Basal Cell Carcinoma Expanding Around Central Hypertrophic Scarring: A Case Report.

A case of annular basal cell carcinoma (BCC) with central atrophic scarring that developed secondary to spontaneous regression has been reported. We present a novel case of a large, expanding nodular and micronodular BCC with annular morphology with central hypertrophic scarring. A 61-year-old woman presented with a two-year history of a mildly itchy lesion on the right breast. Previously diagnosed as an infection, the lesion persisted after treatment with topical antifungal agents and oral antibiotics. Physical examination revealed a 5x6 cm plaque consisting of a pink-red arciform/annular edge with an overlying scale crust and a large, centrally positioned, firm, alabaster-colored portion. A punch biopsy of the pink-red rim revealed nodular and micronodular BCC features. A deep shave biopsy of the central bound-down plaque showed histopathology of scarring fibrosis with no findings of BCC regression. The malignancy was treated with two sessions of radiofrequency destruction, which led to the resolution of the tumor with no recurrence to date. Contrary to the previously reported case, BCC in our case was expanding, associated with hypertrophic scarring, and showed no signs of regression. We discuss several possible etiologies of the scarring centrally. With further awareness of this presentation, more such tumors can be detected at early stages to facilitate prompt treatment and prevent local morbidity.