Urticating Hashimoto-Pritzker Langerhans cell histiocytosis

Congenital self-healing reticulohistiocytosis with spontaneous regression

Congenital self-healing reticulohistiocytosis is a rare, benign, self-limiting variant of Langerhans cell histiocytosis (LCH). LCH encompasses a group of idiopathic disorders characterized by the clonal proliferation of Langerhans cells. Congenital self-healing reticulohistiocytosis typically appears at birth or in the neonatal period as isolated cutaneous lesions, often appearing as multiple crusted papules with no systemic findings. Although clinical features seem aggressive, the lesions tend to involute spontaneously within weeks to a few months leaving residual hypo or hyperpigmented macules. Timely diagnosis with histology, immunocytochemistry, and electron microscopic studies will eliminate unnecessary therapeutic interventions. Although mostly self-resolving, it carries a variable clinical course in some patients with cases of extracutaneous involvement and/or recurrences. Hence, reassurance and long-term follow-up play key roles in the management of this disease.

A case of cutaneous mastocytosis in a child with prominent Langerhans cell infiltration

We recently encountered a 2-year-old boy with slightly infiltrative brown papules on the face, trunk, and extremities. Stroking of one of the papules produced an urticarial wheal (positive Darier's sign). Histopathologic tests revealed a dense infiltration of mast cells containing numerous granules and showing metachromasia under Toluidine blue staining. Immunohistochemical tests revealed that these cells were positive for CD68 and for c-kit. In addition, dermal dendritic cells that were positive for S100 and CD1a immunostaining were intermingled with the mast cells. We confirmed through electron microscopy that the dermal dendritic cells that were observed adjacent to the infiltration of mast cells had Birbeck granules in their cytoplasm, namely Langerhans cells. However, because of the greater numbers of mast cells than Langerhans cells, and because of the absence of both monomorphic LC proliferation and systemic symptoms of Langerhans cell histiocytosis, the present case favors a diagnosis of cutaneous mastocytosis in a child with Langerhans cell infiltration.

Histiocitosis de células de Langerhans

Histiocytoses originate from the proliferation of mononuclear phagocytes in different tissues. These entities make up a heterogeneous group, and are mainly classified as Langerhans cell histiocytoses and non-Langerhans cell histiocytoses. Langerhans cell histiocytoses have as a common characteristic the proliferation of dendritic antigen-presenting cells with phenotypical and ultrastructural characteristics of Langerhans cells. Infiltration may be limited to one organ, or may be disseminated. The prognosis and the treatment especially depend on the age of the patient and the number and dysfunction of the organs involved. Its etiopathogenesis is unknown, although most researchers currently believe that an alteration in the regulation of the immunological system occurs in these patients.

Congenital Langerhans cell histiocytosis: the self-healing variety

Congenital self-healing Langerhans cell histiocytosis (CSHLCH) is a rare variant of Langerhans cell histiocytosis, presenting at birth or in the neonatal period with cutaneous lesions that involute spontaneously. Affected infants are otherwise well with no systemic illness. A case of CSHLCH, probably the first case report from India, is described. The patient presented on the third day of life with multiple papulonodular lesions over the body, with no systemic involvement. The lesions spontaneously regressed by 6 months of age, with no evidence of relapse at 1 year of age. Although CSHLCH is a benign and self-limited condition, long-term follow-up for evidence of relapse is emphasized.