February 2017 Case

Andrew Siref, MD (Resident) and Wonwoo Shon, DO (Faculty)

The patient is a 6-day old baby girl, born at 40w2d via normal, spontaneous vaginal delivery following an uneventful pregnancy. Microcephaly and skin lesions were noted at birth. The rash appeared as scattered, erythematous, and hyperpigmented (coalescing) macules on the neck, trunk, and extremities, seemingly along the lines of Blashko.

At 30 hours of life, the patient had a witnessed seizure and was transferred to the NICU. Continuous EEG monitoring revealed frequent seizure activity. MRI of the brain demonstrated innumerable, small cortical and subcortical foci of infarction, most with associated hemorrhage.

Incontinentia pigmenti

Incontinentia pigmenti , also known as Bloch-Sulzberger disease, is a rare X-linked dominant genodermatosis caused by mutations in the IKK-γ gene (IKBKG). This condition is generally not seen in males as the trait is typically lethal in utero in the absence of a normal X-chromosome. Skin lesions are typically present in the first few weeks of life and are situated along the lines of Blashko. The linearity of the lesions is attributed to mosaicism caused by lyonization (X-inactivation). Extracutaneous abnormalities involving the teeth, bones, CNS, and eyes are common and sometimes can present as the dominant clinical features of the disorder. Seizures and microcephaly are among the most common findings involving the CNS. Peripheral eosinophilia is also a common finding.

Incontinentia pigmenti is characterized by four stages: vesicular, verrucous, hyperpigmented, and hypopigmented. However, stages may overlap and not all patients express each stage. Subungual tumors can also occur in the late phase of incontinentia pigmenti. These tumors are very painful and frequently involve multiple digits.

Sequencing of IKBKG in this patient revealed a c.766C>T mutation which was present in some - but not all - cells, consistent with somatic mosaicism. The presence of this variant is consistent with a diagnosis of incontinentia pigmenti.

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2. James, William D., MD, Elston, Dirk M., MD, and Berger, Timothy G., MD. Andrews' Diseases of the Skin, 12th edition. Philadelphia, PA: Elsevier; 2011.

3. Busam, Klaus J., MD and Goldblum, John R., MD, FACP, FASCP, FACG. Dermatopathology, 2nd edition. Philadelphia, PA: Saunders, an imprint of Elsevier Inc.; 2016.