Most common type of skin carcinoma on face, in light skinned, is: March 2013
**Core Concept**
Basal cell carcinoma (BCC) is a malignant skin tumor that originates from the basal cell layer of the epidermis, often occurring on sun-exposed areas such as the face, particularly in individuals with fair skin. It is characterized by its slow growth and local invasiveness.
**Why the Correct Answer is Right**
BCC is the most common type of skin cancer, accounting for approximately 80% of all skin cancers in fair-skinned individuals. This is due to its high susceptibility to ultraviolet (UV) radiation from the sun, leading to mutations in the TP53 tumor suppressor gene and activation of the hedgehog signaling pathway. The resulting tumor growth is often asymptomatic, but may present as a pearly nodule, ulcer, or patch, depending on the subtype. Early detection is crucial, as BCC can cause significant local destruction if left untreated.
**Why Each Wrong Option is Incorrect**
**Option A:** Squamous cell carcinoma (SCC) is a different type of skin cancer, arising from the squamous cell layer of the epidermis. While it is more aggressive than BCC, it is less common on the face in light-skinned individuals.
**Option C:** Bowen's disease is an early form of SCC, characterized by an in situ carcinoma of the squamous epithelium. It is less common than BCC and typically presents as a solitary, well-defined patch or plaque.
**Option D:** Erythroplasia of Queyrat is a rare condition, typically presenting as a red, velvety patch or plaque on the mucosal surfaces, most commonly in the genital area. It is not typically associated with sun exposure.
**Clinical Pearl / High-Yield Fact**
BCC is often referred to as "nose cancer" due to its high incidence on the nasal ala. Early detection is critical, as BCC can cause significant local destruction, including bone and cartilage erosion.
**✓ Correct Answer: B. Basal cell carcinoma**