A variety of cutaneous and subcutaneous nodules may be detected in the newborn. Most are benign and self-limited, such as cysts, subcutaneous fat necrosis, and certain soft tissue tumors. However, some may be because of malignancy or be a marker for other abnormalities, such as neural tube defects.
Cysts, subcutaneous fat necrosis, and tumors that present at birth or in early infancy are reviewed here. Other benign skin lesions, vesiculopustular and bullous disorders, and congenital pigmented and vascular disorders in the newborn are discussed separately. (See "Benign skin and scalp lesions in the newborn and young infant" and "Vascular lesions in the newborn" and "Vesiculobullous and pustular lesions in the newborn".)
Common types of cysts include dermoid cysts and epidermal cysts. Other types, such as branchial cleft or thyroglossal duct cysts, may also occur.
Dermoid cysts and sinuses — Dermoid cysts are congenital subcutaneous lesions that are usually distributed along embryonic fusion lines of the facial processes or within the neural axis . The most common locations are overlying the anterior fontanelle, the bregma (junction of the coronal and sagittal sutures), upper lateral region of the forehead, lateral upper eyelid, and submental region, although lesions can occur anywhere on the scalp, face, spinal axis, or other body sites.
Dermoid cysts are almost always present at birth, although subtle lesions may not be noticed until, for example, trauma causes inflammation (picture 1). They present as small (1 to 4 cm in diameter), slow-growing, asymptomatic rubbery subcutaneous nodules that are usually solitary (picture 2). They are nonpulsatile, noncompressible, nontender masses that appear skin-colored or blue . The skin overlying the cyst appears normal unless a pit or a sinus is present.