Page 125 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-40 Rashes

PRESENTATION OF LANGERHANS CELL HISTIOCYTOSIS IN CHILDHOOD
LANGERHANS CELL
HISTIOCYTOSIS

Langerhans cell histiocytosis (LCH) is a rare disorder
caused by the proliferation of Langerhans cells in
various tissues. Historically, the disease was categorized
based on the grouping of symptoms and organs affected,
with names such as Letterer-Siwe disease and Hand-
Schüller-Christian disease. Over the last decade, the
classification of LCH has been standardized. The new
classification does not remove the eponyms that have
been used for years but rather categorizes the LCH into
subgroups based on prognosis and amount of involve-
ment. These histiocytoses are a heterogeneous group
of diseases that may affect both the skin and various
internal organs. The main pathological finding is the
accumulation of pathological Langerhans cells within
the affected tissue. The diagnosis is made on clinical,
histological, laboratory, and radiographic findings. The
newer classification of LCH is based on the number of
organ systems involved. It includes the subtypes of
restricted single-system LCH, extensive multisystem
LCH, and single-system pulmonary LCH. The exten-
sive multisystem form of LCH can be further divided Papules and macules
into those cases with and without organ dysfunction. studded with multiple The diaper area is one of the more common areas
Prognosis and therapy depend on the organ systems petechiae are char- of involvement with Langerhans cell histiocytosis.
involved and the number of systems implicated. Optimal acteristic for Langerhans This disease should be in the differential diagnosis
therapy has yet to be determined. cell histiocytosis. of diaper rash that does not respond to therapy for
Clinical Findings: LCH is a very rare condition that dermatitis, especially if petechiae are present.
affects approximately 8 of every 1,000,000 people.
There is a 2 : 1 male-to-female predilection, and all
races are affected equally. Usually, the condition is first
noticed in childhood, but adult-onset disease does
occur. LCH isolated to the skin has one of the best
prognoses of all of the forms of LCH. Most cases of
LCH manifest first in the skin, even before the develop-
ment of systemic findings; therefore, all patients with
cutaneous LCH should be routinely screened for sys-
temic diseases.
In infants, the typical presenting skin findings are
those of a persistent papulosquamous eruption on the
scalp that resembles cradle cap. On closer inspection,
small petechiae are observed. These petechiae are very
characteristic for LCH and can be easily overlooked.
The scalp form is often misdiagnosed as seborrheic
dermatitis early in infancy, and frequently it is not until
the child is 3 to 6 months old and the rash has persisted
that the diagnosis of LCH is entertained. The other
common presentation in children is that of persistent Sheets of Langerhans cell
diaper dermatitis. The rash has a unique predisposition histiocytes with abundant pink
cytoplasm and folded nuclei
to affect the groin folds and can be quite inflammatory with prominent nuclear
and resistant to typical therapy for irritant contact der- grooves
matitis or diaper rash. The groin rash appears as red to
yellowish-orange papules that coalesce into plaques.
Ulcerations and erosions are common. Superinfection
with bacteria often leads to an odor. Both of these forms
are almost always considered to be another diagnosis Disseminated Langerhans cell histiocytosis lesions in axilla and on neck and trunk
before LCH is considered and a skin biopsy is done to
prove the diagnosis. Other skin findings that can be
observed by the astute clinician are adenopathy, ear
inflammation and drainage from the external ear, and systemic complaints. The most common extracutane- delineate the extent of disease. If one area of bony
soft tissue swelling. The soft tissue swelling is seen only ous form of LCH, formerly designated eosinophilic involvement is found, a skeletal survey should be per-
in those patients with underlying bony disorders. Gin- granuloma, is now called single-system unifocal bone formed to evaluate for other silent bony lesions, which
gival hypertrophy may also be seen, but it is often disease. Children present with a painless to slightly can occur in up to 15% of cases. The involved bone has
subtle. Infants may also have premature eruption of tender soft tissue swelling overlying the bony area of a radiolucent appearance that is sharply demarcated
their teeth, which is most commonly noticed by the still involvement, most commonly the calvarium. Palpation from the surrounding bone. Bony involvement has been
breast-feeding mother. of the swelling reveals the fluctuant nature of the soft described to occur in almost every bone in the body.
Twenty percent of patients do not exhibit any cutane- tissue distention, and in some cases the defect in the Most cases are inconsequential, but if the involvement
ous signs of disease and present solely with varying underlying bone can be felt. Plain radiographs can help affects a critical portion of the spine, the possibility of

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