Minor Anomalies and Birthmarks - November 2004

Minor anomalies—defined as physical differences—are commonly encountered during the newborn exam. In fact, at least 4% of newborn infants have a single minor anomaly. These anomalies typically do not have clinical significance. However, it is important to recognize that they may be associated with major occult malformations or genetic syndromes:

  • 3% of infants with a single minor anomaly have an associated major malformation;
  • 0.8% have two minor anomalies with a 10% risk of associated major malformations;
  • less than 0.5% have three minor anomalies with a 20% risk of a major malformation.

    • Birthmarks are seen in 8-10% of newborns. Most are vascular or pigmentary lesions of no clinical significance, but some may be associated with malformations and genetic diseases. The tables below list some of the more commonly encountered lesions and anomalies, along with associated findings and suggested investigations.

    Summary of Selected Minor Anomalies and Associated Findings

    Clinical Feature: Ear tags - 1.7/1000; Autosomal dominant
    Syndrome(s) to Consider: Oculoauriculovertebral spectrum Goldenhar Syndrome)
    Associated Findings: Microtia, middle/inner ear involvement; facial asymmetry, epibulbar dermoids, vertebral anomalies
    Suggested Investigations: Hearing evaluation; Consider ophthalmologic evaluation; Spinal radiographs if associated findings noted

    Clinical Feature: Ear pit - 1-5%; Autosomal dominant
    Syndrome(s) to Consider: Branchio-otorenal syndrome
    Associated Findings: External ear anomalies, branchial cleft fistulae, renal anomalies
    Suggested Investigations: Hearing evaluation in isolated pits; Renal sonography if branchial clefts or pits

    Clinical Feature: Dorsal cutaneous lesion (note: 74% are simple sacral dimples)
    Syndrome(s) to Consider: Cutis aplasia; hemangioma, hairy patches, atypical sacral dimples (>5mm and >2.5 cms from anus); Simple dimple is <5 mm and within 2.5 cms of anus
    Associated Findings: Occult spinal dysraphism
    Suggested Investigations: If high risk stigmata then investigate via spinal ultrasonography if <3 mo of age; Spinal magnetic resonance imaging if >3 mo of age. No evaluation for simple sacral dimple

    Clinical Feature: Transverse palmar crease - Can be a normal variant: in ~ 4% Caucasians & 17% Chinese; bilateral in 1% Caucasians and 6.6% Chinese
    Syndrome(s) to Consider: Trisomy 21 (45% of patients with Down’s syndrome have a single transverse palmer crease)
    Associated Findings: Cardiac abnormalities, typical facial features, mental retardation
    Suggested Investigations: Karyotyping; Echocardiography if trisomy 21

    Clinical Feature: Single umbilical artery (SUA) - Incidence 0.3 – 0.9%
    Syndrome(s) to Consider: Increased risk in infants of diabetic mothers, IUGR, prematurity, advanced maternal age and other congenital anomalies
    Associated Findings: Most associated anomalies (GU, GI & cardiac) are detected on exam with the exception of renal anomalies which are found in 7 - 18% of infants with SUA.
    Suggested Investigations: When found on prenatal ultrasound, a targeted ultrasound and fetal echo recommended. Postnatal renal ultrasound at 1-2 weeks of age unless ultrasound done after 22 weeks gestation and showed normal kidneys.

    Neonatal Skin Lesions That May be Clues to More Serious Disorders

    Hyperpigmented Birthmarks
    Café au lait macules (CALMs): These are common in newborns and range from 2 mm to 20 cm. Typically seen on unexposed skin. The incidence is 18% in African Americans and 0.3% in Caucasians and Chinese. Six or more CALMs of >5 mm are presumptive of NF1; associated findings of axillary or inguinal freckling, Lisch nodules and optic gliomas. Monitor for the development of the associated findings if >3 CALMs in Caucasians and >5 in African Americans.
    Congenital melanocytic nevi (CMN): Small nevi are seen in 1-2% of neonates. The risk of malignancy is less than 2 %- clinical monitoring only; Large CMNs (>20cm in diameter) have a 6-8% risk of malignancy by 3-5 yrs of age, and partial or complete prophylactic excision is recommended.

    Hypopigmented Birthmarks (“white spots”)
    Three or more should prompt evaluation for tuberous sclerosis. Differential diagnosis includes piebaldism, vitiligo and postinflammatory hypopigmentation.

    Vascular Birthmarks
    This is the most common lesion, seen in nearly 50% of newborns. It disappears by 2 yrs of age. They most typically are found on the forehead, glabella, nose, upper eyelids, the nape of neck and upper lip.

    Port-wine stains
    Capillary malformations that do not involute. PWS are associated with Sturge Weber syndrome and Klippel-Trenaunay syndrome. An MRI of brain and ophthalmologic exam are recommended at 6 months of age if the PWS is found in the distribution of the trigeminal nerve.

    Lymphatic malformations (cystic hygroma)
    Ultrasound recommended to delineate the size and potential compression of surrounding structures.

    Vascular Tumors
    Hemangiomas occur in 1 - 2.5% of newborns. Most are superficial, proliferate to reach their maximal size at 6 - 8 months and then begin to involute. These are seen with greater frequency in pre-term infant and females. Deeper lesions may proliferate for 12 - 14 months; most involute by 3 years of age. MRI of spine recommended if present in midline lumbosacral area; bronchoscopy if in “beard” distribution; monitoring of vision if in ophthalmic distribution.

    It is important to consider each anomaly against the clinical circumstance, ethnic and familial background and gender before assigning clinical significance to any finding and undertaking extensive investigation.



    References:
    Adam and Hudgins; Neoreviews 2003, 4, No. 4
    Hernandez and Morelli, Neorevews 2003, 4, No. 10


    This information provided by California Pacific Medical Center's Division of Neonatology
    Steven Goldman, M.D., Ghizala Kaleem, M.D., David Lee, M.D., Kathleen Lewis, M.D., Chris Retajczyk, M.D., Terri Slagle, M.D.
    Tel. (415) 600-6211