A farmer presented with a black mole on the check. It increased in size, more than 6mm with sharply defined borders with central black lesion, what could be the diagnosis?

**Core Concept**
Superficial spreading melanoma (SSM) is a common type of skin cancer characterized by its radial growth phase, where melanocytes proliferate along the epidermal-dermal junction, forming a horizontal growth pattern. This subtype often presents as a flat or slightly raised, irregularly shaped lesion with well-defined borders, which is consistent with the description provided.

**Why the Correct Answer is Right**
The patient's presentation of a black mole on the cheek with sharply defined borders and central black lesion is highly suggestive of SSM. This subtype accounts for approximately 70% of all melanomas and typically arises on sun-exposed skin. The growth pattern of SSM allows it to spread along the epidermal-dermal junction, often resulting in a larger, flat lesion before invading the dermis.

**Why Each Wrong Option is Incorrect**
**Option A:** Acral lentigo melanoma typically presents as a pigmented lesion on the palms, soles, or subungual areas, which is not consistent with the patient's cheek location.

**Option C:** Lentigo maligna melanoma (LMM) usually occurs on sun-damaged skin, particularly on the face, but it tends to have a more chronic and radial growth pattern, often with a mix of pigmentation and atrophy.

**Option D:** Nodular melanoma (NM) is a more aggressive subtype characterized by a vertical growth phase, where melanocytes invade the dermis in a radial and vertical pattern. NM often presents as a raised, nodular lesion with a smooth or irregular surface, which does not match the patient's description.

**Clinical Pearl / High-Yield Fact**
When evaluating pigmented skin lesions, remember the "ABCD" rule: Asymmetry, Border irregularity, Color variability, and Diameter > 6mm. The presence of any of these features increases the likelihood of a malignant melanoma.

**✓ Correct Answer: B. Superficial spreading melanoma**

✓ Correct Answer: B. Superficial spreading melanoma