Biopsy from a mole on the foot shows cytologic atypia of melanocytes and diffuse epidermal inflitration by anaplastic cells, which are also present in the papillary and reticular dermis. The most likely diagnosis is –
## **Core Concept**
The question describes a skin lesion with cytologic atypia of melanocytes and diffuse infiltration by anaplastic cells across different layers of the skin, including the epidermis, papillary dermis, and reticular dermis. This presentation suggests a malignant skin tumor originating from melanocytes.
## **Why the Correct Answer is Right**
The description provided matches the histopathological features of **acral lentiginous melanoma**, a subtype of malignant melanoma. This type of melanoma is characterized by its location on the palms, soles, and nail beds, and it exhibits cytologic atypia of melanocytes along with pagetoid spread (infiltration of the epidermis by atypical melanocytes). The presence of anaplastic cells in the papillary and reticular dermis indicates a high-grade malignancy with potential for deep invasion.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, other types of skin cancers like basal cell carcinoma or squamous cell carcinoma would not present with cytologic atypia of melanocytes.
- **Option B:** This option is also not provided, but if it referred to another type of melanoma or skin cancer not matching the description, it would be incorrect based on the specific histological features mentioned.
- **Option C:** Similarly, without the specific content of Option C, if it does not align with the characteristics of acral lentiginous melanoma or another specific melanoma subtype that matches the given description, it would be incorrect.
- **Option D:** If Option D does not describe acral lentiginous melanoma or a condition with similar histopathological features, it would be incorrect.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **acral lentiginous melanoma** is one of the most common types of melanoma in people of color and often presents on the palms or soles. Early detection is crucial, and any suspicious skin lesions in these areas should be biopsied for histopathological examination.
## **Correct Answer:** . Acral Lentiginous Melanoma.