In a case of primary melanoma of 1-2mm depth, margins of excision of surrounding normal skin should be –
**Core Concept**
Primary melanoma is a type of skin cancer that originates from melanocytes, the pigment-producing cells in the skin. The depth of invasion is a critical factor in determining the prognosis and management of melanoma. For superficial melanomas with a depth of 1-2 mm, the goal of surgical excision is to remove the tumor completely while preserving surrounding normal skin.
**Why the Correct Answer is Right**
For melanomas with a depth of 1-2 mm, the American Joint Committee on Cancer (AJCC) recommends a surgical margin of at least 1 cm to ensure complete removal of the tumor. This is based on the concept of the "radical margin," which refers to the distance between the edge of the tumor and the surgical margin. A 1-cm margin provides a high likelihood of removing all tumor cells, reducing the risk of local recurrence. The use of a 1-cm margin is also supported by studies demonstrating improved survival rates in patients with thin melanomas who undergo wide excision.
**Why Each Wrong Option is Incorrect**
**Option A:** A 0.5-cm margin may not be sufficient to remove all tumor cells, particularly for thicker melanomas. This option is incorrect because it may lead to incomplete excision and increased risk of local recurrence.
**Option B:** A 3-cm margin is excessive for superficial melanomas with a depth of 1-2 mm, as it would result in unnecessary removal of healthy skin and tissue. This option is incorrect because it would lead to significant morbidity and decreased quality of life.
**Option C:** A 2-cm margin is not recommended for primary melanoma, as it is not supported by evidence and may not provide a significant improvement in recurrence rates. This option is incorrect because it is not based on current guidelines or research.
**Clinical Pearl / High-Yield Fact**
When excising a melanoma, it is essential to obtain a margin of at least 1 cm to ensure complete removal of the tumor and prevent local recurrence. This principle applies to all primary melanomas, regardless of depth or thickness.
**Correct Answer: C. 2 cm.**