Langerhans cell histiocytosis, a new clinical phenotype of x-linked lymphoproliferative disease?

Hemophagocytic Lymphohistiocytosis in Langerhans Cell Histiocytosis: A Case Series and Literature Review

Langerhans cell histiocytosis (LCH) is characterized pathologically by langerin-positive (CD207+) dendritic cell proliferation and is considered by some as a myeloid neoplastic disorder. Hemophagocytic lymphohistiocytosis (HLH) is associated with immune dysregulation characterized by the accumulation of activated macrophages and hypercytokinemia. However, these 2 histiocytosis rarely coexist. Currently, the etiology, risk factors, optimal therapy, and outcomes of LCH-HLH remain unclear. We reviewed the medical records of 7 LCH-HLH patients from our hospital and analyzed 50 LCH-HLH patients reported in scientific literature. The median age of LCH onset of these 57 LCH-HLH patients was 1 year, and 91% (52/57) of patients diagnosed as LCH were less than 2 years old. Fifty-six LCH-HLH patients belonged to the multisystem LCH category and 84% (47/56) patients had risk-organ involvement. Twenty-three LCH-HLH patients were complicated with infection and 3 patients had a primary pathogenic mutation of HLH. Overall, 90% of LCH patients developed HLH at the diagnosis or during chemotherapy. Of the 57 LCH-HLH patients, 15 died. Multisystem LCH patients with risk-organ involvement under 2 years old were most likely to develop HLH when complicated with infection at diagnosis or during chemotherapy. Identifying LCH-HLH patients during early stages and treating them with prompt chemotherapy, hematopoietic stem cell transplantation, or supportive therapies are important for better survival.

Langerhans cell histiocytosis complicated with hemophagocytic lymphohistiocytosis in a boy with a novel XIAP mutation: A case report

RATIONALE

X-linked lymphoproliferative syndromes (XLPs) are rare, yet often fatal primary immunodeficiency diseases, which rarely manifest as Langerhans cell histiocytosis (LCH) complicated with hemophagocytic lymphohistiocytosis (HLH). Clinical data of a case of XLP-2 manifesting as LCH complicated with HLH was retrospectively analyzed to determine the etiology and causal gene.

PATIENT CONCERNS AND DIAGNOSIS

The diagnosis of multisystem LCH was confirmed by skin biopsy and other examinations in a 13-month boy with recurrent ear discharge, fever and hemorrhagic papules for 3 months. A good therapeutic response to LCH-III protocol-directed induction chemotherapy was achieved but unremitting HLH developed 6 weeks after the initiation of induction chemotherapy. To identify possible underlying genetic causes, gene mutation analysis was undertaken. A novel XIAP gene mutation (c.99delT, p.F33fsX37) was documented.

INTERVENTIONS

After the diagnosis of HLH had been confirmed, HLH-2004-directed chemotherapy was instituted.

OUTCOMES

The clinical condition of the patient had become progressively deteriorating after 8-week chemotherapy of HLH-2004 protocol, requiring frequent infusions of RBC suspensions and apheresis platelets. His parents decided to receive no further therapy, and the patient died soon after discharge.

LESSONS

Meticulous laboratory investigations including genetic studies should be undertaken in young children with LCH complicated with HLH and poor therapeutic response.