Langerhans cell histiocytosis affects individuals of any age group but more often is seen in pediatric patients. The incidence of LCH is approximately 4.6 cases per million children.18 The pathogenesis is secondary to pathologic Langerhans cells, characterized as a clonal myeloid malignancy and dysregulation of the immune system.18,19
Diagnosis
A thorough physical examination is essential in patients with suspected LCH. Additionally, diagnosis of LCH is heavily based on histopathology of tissue from the involved organ system(s) with features of positive S-100 protein, CD1a, and CD207, and identification of Birbeck granules.20 Imaging and laboratory studies also are indicated and can include a skeletal survey (to assess osteolytic and organ involvement), a complete hematologic panel, coagulation studies, and liver function tests.18,21
Management
Management of LCH varies based on the organ system(s) involved along with the extent of the disease. Dermatology referral may be indicated in patients presenting with nonresolving cutaneous lesions as well as in severe cases. Single-organ and multisystem disease may require one treatment modality or a combination of chemotherapy, surgery, radiation, and/or immunotherapy.21
Infantile Hemangioma
Presentation
Infantile hemangioma (IH) is the most common benign tumor of infancy and usually is apparent a few weeks after birth. Lesions appear as bright red papules, nodules, or plaques. Deep or subcutaneous lesions present as raised, flesh-colored nodules with a blue hue and bruiselike appearance with or without a central patch of telangiectasia22-24 (Figure 6). Although all IHs eventually resolve, residual skin changes such as scarring, atrophy, and fibrosis can persist.24
Figure 6. Ulcerated superficial infantile hemangioma in an 8-weekold neonate. Crusting and erosion were noted at the center of the red plaque with white discoloration surrounding the crust, an indicator of prior ulceration.
The incidence of IH has been reported to occur in up to 4% to 5% of infants in the United States.23,25 Infantile hemangiomas also have been found to be more common among white, preterm, and multiple-gestation infants.25 The proposed pathogenesis of IHs includes angiogenic and vasogenic factors that cause rapid proliferation of blood vessels, likely driven by tissue hypoxia.23,26,27
Diagnosis
Infantile hemangioma is diagnosed clinically; however, immunohistochemical staining showing positivity for glucose transporter 1 also is helpful.26,27 Imaging modalities such as ultrasonography and magnetic resonance imaging also can be utilized to visualize the extent of lesions if necessary.25
Management
Around 15% to 25% of IHs are considered complicated and require intervention.25,27 Infantile hemangiomas can interfere with function depending on location or have potentially fatal complications. Based on the location and extent of involvement, these findings can include ulceration; hemorrhage; impairment of feeding, hearing, and/or vision; facial deformities; airway obstruction; hypothyroidism; and congestive heart failure.25,28 Early treatment with topical or oral beta-blockers is imperative for potentially life-threatening IHs, which can be seen due to large size or dangerous location.28,29 Because the rapid proliferative phase of IHs is thought to begin around 6 weeks of life, treatment should be initiated as early as possible. Initiation of beta-blocker therapy in the first few months of life can prevent functional impairment, ulceration, and permanent cosmetic changes. Additionally, surgery or pulsed dye laser treatment have been found to be effective for skin changes found after involution of IH.25,29
Differential Diagnosis
The differential diagnosis for IH includes vascular malformations, which are present at birth and do not undergo rapid proliferation; sarcoma; and kaposiform hemangioendothelioma, which causes the Kasabach-Merritt phenomenon secondary to platelet trapping. Careful attention to the history of the skin lesion provides good support for diagnosis of IH in most cases.