Histiocytic proliferations

The changing landscape of pediatric histiocytoses: Birth, life, and transdifferentiation of pediatric histiocytes

Histiocytic neoplasms in the children are very rare, and histiocytoses can occur in the perinatal period. The presumed origins and presentation of specific histiocytoses in the pediatric age group are described. Common and newly described histiocytoses are presented including Langerhans cell histiocytosis, Rosai-Dorfman disease, histiocytic sarcoma, ALK positive histiocytosis, and hemophagocytic lymphohistiocytosis. Molecular findings common to pediatric histiocytoses are also discussed.

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.

Solitary extranodal Rosai-Dorfman disease of the mandible: an exceedingly rare presentation

Sinus histiocytosis with massive lymphadenopathy, generally known by the name of Rosai-Dorfman disease is a rare benign condition principally affecting cervical lymph nodes. Concurrent extra-nodal disease frequently occurs, however, solitary extra-nodal disease involving the mandible is exceedingly rare with less than five reported cases in the English literature. We describe a case of primary involvement of the mandible in a 27-year-old female, and discuss the differential diagnosis of this disease with other histiocytic lesions.

A rare case of CD1a-negative Langerhans cell histiocytosis of the central nervous system in a child

Langerhans cell histiocytosis is a dendritic cell disorder with a wide spectrum of severity and presentations. Histopathology typically demonstrates a proliferation of Langerhans cells and a lymphohistiocytic inflammatory infiltrate with eosinophils. The diagnosis is supported by immunohistochemistry with the cell markers S100, CD1a, CD68, and Langerin [Blood, 126, 2015, 26 and N Engl J Med, 331, 1994, 154].