Congenital Langerhans cell histiocytosis presenting in a 27-week-gestation neonate

Langerhans cell histiocytosis: an unusual cause of vesicular rashes in a neonate

The skin manifestations of Langerhans cell histiocytosis (LCH) in the neonate have a heterogenous presentation and can mimic other causes of neonatal rashes. We report an uncommon case of LCH in a term female neonate presenting with non-specific papules and vesicles from the first day of life. There was a maternal history of genital herpes simplex virus (HSV) infection in the third trimester. Blood, cerebrospinal fluid, surface swabs and vesicular fluid were negative for HSV by PCR, and a skin biopsy confirmed the diagnosis of LCH. Further investigations for systemic involvement returned negative. Our case emphasises the variable and non-specific presentation of neonatal cutaneous LCH, which can progress to or be part of multisystem disease.

Langerhans cell histiocytosis: A rare aetiology for fetal pleural effusion

OBJECTIVE

We present fetal pleural effusions associated with Langerhans cell histiocytosis (LCH).

CASE REPORT

We report a case of fetal pleural effusion in late pregnancy. Due to developing rapidly over short period of time, the baby was delivered by caesarean section at 34 weeks gestation. Generalised oedema, sparse haemorrhagic papules, pulmonary involvement, mediastinal mass and liver dysfunction were identified postnatally. Structural malformations, maternal-fetal blood type incompatibility, chromosomal abnormalities and viral infection were excluded. Mediastinal mass biopsy and immunohistochemical examinations confirmed the diagnosis of Langerhans cell histiocytosis (LCH). The baby is currently in a stable condition and undergoing regular chemotherapy.

CONCLUSIONS

Congenital LCH is a rare aetiology of fetal pleural effusions.

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.