Pigmented macules over palm seen on clinical examination. Histologically, proliferating melanocytes are found at the dermoepidermal junction. Diagnosis?
## **Core Concept**
The question describes a clinical scenario involving pigmented macules over the palm, with histological findings of proliferating melanocytes at the dermoepidermal junction. This scenario points towards a melanocytic lesion. The key here is to differentiate between various pigmented lesions based on their histological characteristics and clinical presentation.
## **Why the Correct Answer is Right**
The description given—pigmented macules over the palm with proliferating melanocytes at the dermoepidermal junction—is highly suggestive of **acral lentiginous melanoma**. This type of melanoma is a subtype of malignant melanoma that occurs on the palms, soles, and under the nails (subungual). It is characterized by the proliferation of melanocytes at the dermoepidermal junction, which is a hallmark of melanoma in situ or early invasive melanoma. Acral lentiginous melanoma is the most common type of melanoma in people of color and often presents as a slowly enlarging pigmented lesion.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, other types of melanocytic nevi or lesions like junctional nevi might be considered. However, junctional nevi are usually benign and have a more uniform appearance, with nests of melanocytes at the dermoepidermal junction.
- **Option B:** Similarly, not provided, but another possibility could be a benign lesion like a melanocytic nevus. However, these are less likely to show a significant proliferation of melanocytes at the junction in an acral location.
- **Option C:** If this option suggested a different type of skin cancer or a benign condition not consistent with the histological description, it would be incorrect based on the specifics of the clinical and histological presentation.
- **Option D:** Assuming this is another type of skin lesion, it would be incorrect if it does not match the clinical and histological features described for acral lentiginous melanoma.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that any new or changing pigmented lesion, especially on acral surfaces (palms, soles, under nails), should raise suspicion for melanoma. The ABCDE rule (Asymmetry, Border irregularity, Color variegation, Diameter >6mm, Evolving) is a useful guide for screening, but acral lentiginous melanomas often do not follow this rule, making clinical vigilance critical.
## **Correct Answer:** . **Acral Lentiginous Melanoma**