Although most neonatal vascular lumps, bumps, and tumors are benign, proper diagnosis is important for prognosis and management. Therefore, knowledge of both common and rare conditions is important when evaluating a neonatal nodule. Differential diagnosis of neonatal vascular nodules must focus on important diagnostic clues that should prompt consideration and evaluation for less common and/or potentially threatening conditions. Infantile hemangioma (IH), congenital hemangioma (CH), venous malformation (VM), lymphatic malformation (LM), kaposiform hemangioendothelioma (KHE) and tufted angioma, and malignant tumors are reviewed here.
Infantile hemangioma, a benign proliferation of capillaries, is the most common tumor of infancy with reported incidence of up to 5% in neonates.1 As such, suspicion for less common lesions is often predicated on identifying features that would be atypical for an IH. A superficial IH presents as a bright red papule, nodule, or plaque, while a deep IH presents as a flesh-colored to bluish nodule. Mixed IHs combine features of both superficial and deep lesions. The distribution may be focal or segmental, with segmental lesions encompassing a larger territory–like distribution and frequently displaying a thin, coarsely telangiectatic appearance.
Knowledge of the natural history of IH generally is crucial in differentiating it from other neonatal lesions. Infantile hemangiomas display a natural history that is distinct and predictable. They typically manifest within the first few weeks of life, though up to 30% present at birth with a premonitory mark, which may be a light red, pink, bluish, or vasoconstricted patch. Thus, mere presence of a lesion at birth is not the feature that distinguishes other congenital lesions from an IH. After initial appearance, IHs undergo a period of proliferation that occurs over 4 to 6 months in most patients. In some cases, areas of proliferation may be subtle, but nonetheless the presence of some areas of increased redness and/or volumetric growth generally is required to firmly establish the diagnosis of IH. Thereafter, IH will involute, a process that begins before 1 year of age in most cases and continues over years. Although IHs undergo involution, complete clearance may not occur, as nearly 70% will leave permanent residua such as fibrofatty masses or anetodermic skin.2 Nevertheless, the presence of a proliferative phase followed by a slower period of involution is a hallmark feature of the IH.
Biopsy and imaging rarely are required for establishing diagnosis of an IH. Histopathology showing a proliferation of capillaries with positive glucose transporter 1 (GLUT-1) staining is characteristic. Imaging with ultrasound reveals a fast-flow lesion. Apart from exceptionally rare cases, a cutaneous IH typically does not cross muscle fascia, and thus alternative diagnoses should be considered for a cutaneous lesion that demonstrates infiltration into nerve, bone, joint, or other deeper tissues. Most IHs do not require treatment; however, a small subset may be associated with complications and thus require intervention. Complications of IH may include impairment of function (eg, vision, feeding, respiratory), ulceration, and risk for permanent disfigurement. When treatment is indicated, the most commonly employed options during the proliferative phase are the topical beta-blocker timolol and the oral beta-blocker propranolol. In addition, certain IHs may be associated with either syndromic presentations and/or visceral involvement, thus requiring further workup (Table).