Congenital Self-Healing Langerhans Cell Histiocytosis

Congenital self-healing reticulohistiocytosis in a newborn: unusual oral and cutaneous manifestations

Background

Congenital self-healing reticulohistiocytosis (CSHRH), also called Hashimoto-Pritzker disease, is a rare and benign variant of Langerhans cell histiocytosis, characterized by cutaneous lesions without extracutaneous involvement.

Case presentation

We present a case of CSHRH with diffuse skin lesions and erosions in the oral mucosa, present since birth and lasting for 2 months, and we perform a review of the literature on Pubmed in the last 10 years.

Conclusions

Our case confirm that lesions on oral mucosa, actually underestimated, may be present in patients with CSHRH. Patients affected by CSHRH require a close follow-up until the first years of life, due to the unpredictable course of Langerhans cell histiocytosis, in order to avoid missing diagnosis of more aggressive types of this disorder.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is caused by clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in lesions that leads to a spectrum of organ involvement and dysfunction. The pathogenic cells are defined by constitutive activation of the MAPK signaling pathway. Treatment of LCH is risk-adapted: patients with single lesions may respond well to local treatment, whereas patients with multisystem disease require systemic therapy. Although survival rates for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 20%. Despite progress made in the treatment of LCH, disease reactivation rates remain above 30%, and standard second-line treatment is yet to be established. Treatment failure is associated with increased risks for death and long-term morbidity, including LCH-associated neurodegeneration. Early case series report promising clinical responses in patients with relapsed and refractory LCH treated with BRAF or MEK inhibitors, although potential for this strategy to achieve cure remains uncertain.

Childhood Langerhans cell histiocytosis: a disease with many faces

BACKGROUND

Langerhans cell histiocytosis (LCH) is a group of diseases characterized by the proliferation and accumulation of Langerhans cells. Clinical presentations of LCH vary widely.

DATA SOURCES

A PubMed search was conducted using Clinical Queries with the key term "Langerhans cell histiocytosis". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. This paper is based on, but not limited to, the search results.

RESULTS

Generally, patients with LCH can be divided into two groups based on the extent of involvement at diagnosis, namely, single-system LCH and multisystem LCH. The involvement may be unifocal or multifocal. Patients with isolated bone lesions typically present between 5 and 15 years of age, whereas those with multisystem LCH tend to present before 5 years of age. The clinical spectrum is broad, ranging from an asymptomatic isolated skin or bone lesion to a life-threatening multisystem condition. Clinical manifestations include, among others, "punched out" lytic bone lesion, seborrheic dermatitis-like eruption, erythematous/reddish-brown crusted/scaly papules/maculopapules/plaques/patches, and eczematous lesions, diabetes insipidus, hepatosplenomegaly, cytopenias, lymphadenopathy, and an acute fulminant disseminated multisystem condition presenting with fever, skin rash, anemia, thrombocytopenia, lymphadenopathy, and hepatosplenomegaly. The diagnosis is clinicopathologic, based on typical clinical findings and histologic/immunohistochemical examination of a biopsy of lesional tissue. Positive CD1a, S100, and/or CD207 (Langerin) immunohistochemical staining of lesional cells is required for a definitive diagnosis. Watchful waiting is recommended for patients with skin-only LCH. Patients with symptomatic or refractory skin-only LCH may be treated with topical tacrolimus/corticosteroids, topical nitrogen mustard, oral methotrexate, or oral hydroxyurea. The current recommended first-line therapy for patients with multisystem LCH is 12 months therapy with prednisone and vinblastine. Mercaptopurine is added for patients with risk organ involvements.

CONCLUSIONS

Because of the broad spectrum of clinical manifestations and the extreme diversity of disease, LCH remains a diagnostic dilemma. Morphological identification of LCH cells and positive immunochemical staining with CD1a, S100, and/or CD207 (Langerin) of lesional cells are necessary for a definitive diagnosis.