Pigmented spindle cell nevus

Pigmented spindle cell nevus (PSCN), also known as Reed nevus, is a type of melanocytic nevus characterized by its distinctive histological appearance. It is a benign skin lesion that typically presents as a small, darkly pigmented macule or papule.

Clinical Presentation

Pigmented spindle cell nevus usually appears as a solitary, well-circumscribed, dark brown to black lesion. It is most commonly found on the lower extremities, particularly the thighs, but can occur on any part of the body. The lesion is typically less than 1 cm in diameter and may be slightly raised.

Histopathology

Under the microscope, pigmented spindle cell nevus is characterized by the presence of spindle-shaped melanocytes arranged in fascicles or bundles. These melanocytes are heavily pigmented, giving the lesion its dark color. The nevus cells are usually confined to the epidermis and the superficial dermis, and there is often a lack of significant cellular atypia or mitotic activity, distinguishing it from malignant melanoma.

Differential Diagnosis

The primary differential diagnosis for pigmented spindle cell nevus includes:

• Malignant melanoma
• Spitz nevus
• Common acquired melanocytic nevus
• Blue nevus

Management

The management of pigmented spindle cell nevus typically involves clinical observation and regular follow-up. If there is any doubt about the diagnosis, or if the lesion shows signs of change, an excisional biopsy may be performed to rule out malignancy. Complete excision with clear margins is usually curative.

Prognosis

The prognosis for pigmented spindle cell nevus is excellent, as it is a benign lesion with no potential for metastasis. However, due to its clinical and histological similarities to malignant melanoma, careful evaluation and monitoring are essential.

See Also

• Melanocytic nevus
• Spitz nevus
• Malignant melanoma
• Dermatology