LANGERHANS CELL HISTIOCYTOSIS IN ADULTS – DIAGNOSTIC CHALLENGE OR ACCIDENTAL FINDING

Langerhans cell histiocytosis (LCH) is an orphan disease that belongs to a group of histiocytic and dendritic cell neoplasms. The group of histiocytoses is very heterogeneous, both clinically and histochemically. The incidence of the disease is 1 per 1 000 000. LCH with isolated lung involvement comprises about half of all single-focal form histiocytoses and differs nosologically from LCH. Pulmonary Langerhans cell histiocytosis has its own histological characteristics, its own development and treatment strategies. Today, there are possibilities of immunohistochemical verification of the diagnosis with the detection of CD1a+, CD207+ antigens, but the range of clinical manifestations and differential diagnosis is wide: random clinical and radiological findings will not always lead to the correct diagnosis. In addition, there are no generally accepted standards for the treatment of adult patients with LCH due to the lack of a strong evidence base. Recently, mutations in the RAS-RAF-MEK-ERK pathway have been found, which has expanded the possibilities of targeted therapy. The diagnostic algorithm taking into account clinical features, diagnostic criteria analysis and choosing the optimal management strategy for the patient with isolated pulmonary histiocytosis is a clinical challenge for an internist.