Bowen’s Disease, or squamous cell carcinoma in situ, is a premalignant skin condition characterized by atypical keratinocyte proliferation confined to the epidermis. It presents as scaly, erythematous plaque resembling benign disorders like eczema or psoriasis, complicating diagnosis. Early treatment is vital to prevent progression to invasive carcinoma.

A 60 year old female with prolonged sun exposure presented with a 17-year history of a solitary pinkish patch on her right lower abdomen. Initially non-pruritic and non-tender, the lesion gradually enlarged and thickened, developing into a pruritic plaque. She was treated with Mupirocin ointment without improvement. Three years thereafter, plaque showed hyperpigmentation, scaling, and increased pruritus. Self-treatment various topicals daily for one month was ineffective, prompting further evaluation. Physical examination revealed ill-defined hyperpigmented plaques with irregular borders, scaling, crusting, and hyperkeratosis on the right lower abdomen. A skin punch biopsy showed basketweave stratum corneum with scale crust, spongiotic epidermis with multiple atypical keratinocytes, and dermal infiltrates of atypical mononuclear cells, lymphohistiocytic cells, eosinophils, melanophages, dilated vessels, and extravasated erythrocytes. Diagnosis of in-situ squamous cell carcinoma. Treated with Imiquimod 5% cream three times weekly, achieving complete regression and no recurrence at six months.

Bowen’s Disease mainly affects older adults with significant sun exposure, aligning with higher incidence in chronically sun-damaged populations. Histopathology with atypical keratinocytes confined to the epidermis differentiates it from invasive carcinoma. Topical Imiquimod, an immune response modifier, effectively induced lesion regression by stimulating local cytokines. This case highlights the importance of early diagnosis and non-invasive treatment to prevent malignant progression.