Benign Skin Lesions

BENIGN MELANOCYTIC LESIONS

What is a nevus?

A cutaneous hamartoma or benign proliferation of cells. Usually refers to a melanocytic nevus.

What are the three histologic types of melanocytic nevi?

Junctional, compound, and intradermal.

True/False: Melanocytes develop from neural crest cells.

True.

During fetal development neural crest cells migrate to what eventual location?

Epidermal side of the dermal–epidermal junction.

What is a blue nevus?

A deep dermal accumulation of melanocytic cells. Its deep dermal location gives a blue, gray, or black appearance.

Can blue nevi become malignant?

Yes, rarely.

What is a Spitz nevus?

A melanocytic nevus that occurs most commonly in children.

Where does a Spitz nevus appear?

Usually presents as a small pink nodule on the face or lower extremities. Histologically composed of pleomorphic and cytologically atypical cells, sometimes confused for a melanoma.

Is the risk of malignancy within a congenital melanocytic nevus (CMN) related to size?

Yes.

When is the risk of malignant transformation of a CMN greatest in childhood?

Usually before age 9.

What is a Becker nevus?

Area of hyperpigmentation and hypertrichosis, most commonly found on the upper back, shoulder, or chest in males. Usually presents at puberty.

What is the recommended treatment for an atypical or dysplastic nevus?

Excision with 2-mm margins.

What is a nevus of Ota?

It is a blue to gray hyperpigmentation of the skin, mucosa, or conjunctiva in the distribution of the trigeminal nerve.

What is a nevus of Ito?

Similar in appearance to a nevus of Ota but found on the neck or shoulder.

What is a Mongolian spot?

Congenital hyperpigmented spot found in the sacrococcygeal region. Usually disappears in the first 3 to 5 years of life.

What is a nevus spilus?

An irregularly shaped light brown macule with darkly pigmented macules or papules scattered randomly within the lesion.

What is a labial lentigo?

Hyperpigmented macule that develops on the lip, usually in young women.

Which autosomal-dominant syndrome consists of multiple lentigines and gastrointestinal polyps?

Peutz-Jeghers syndrome.

What is a halo nevus?

A melanocytic nevus with surrounding depigmentation. This is most frequent on the trunk of teenagers.

BENIGN VASCULAR LESIONS

What is the most common vascular neoplasm of childhood?

Hemangioma.

What is a hemangioma?

It is a benign tumor of vascular endothelium. Presents at age 4 to 8 weeks.

What is the natural history of a hemangioma?

The lesion proliferates for the first 6 months to a year, and then goes through involution (regression). Classically, 50% completely regress by age 5.

What is the most common complication of hemangiomas?