Histiocytosis X skin: causes, symptoms, diagnosis, treatment

Histiocytosis X (syn.: histiocytic medullary reticulosis, malignant reticulohistiocytosis). Langerhans cell histiocytoses are a group that includes Letterer-Siwe disease, Hand-Schüller-Christian disease, eosinophilic granuloma, congenital self-healing reticulohistiocytosis, and histiocytosis of indeterminate cells.

A rare progressive systemic disease of the mononuclear-histiocytic system with neoplastic proliferation of atypical histiocytes and other mononuclear phagocytes. The course of the disease is acute with an average life expectancy of up to 6 months. Hepatosplenomegaly, bone marrow infiltration, enlarged lymph nodes, jaundice, fever, and anemia are observed. H. Rappaport (1966) distinguishes two clinical forms of malignant histiocytosis: a visceral form with early involvement of hematopoietic organs and a cutaneous form, observed in approximately 10% of cases.

In the cutaneous form, clinical findings include plaque-like erythema or multiple papules from brownish to purple in color with a tendency to hemorrhage and ulceration, subcutaneous nodules resembling those in erythema nodosum, purple in color, sometimes observed in early stages of the disease.

Pathomorphology. The skin contains predominantly focal polymorphic infiltrate, localized in this way perivascularly and perifollicularly. A larger infiltrate occupies the deep parts of the dermis and subcutaneous fat tissue. Cytological signs vary greatly. The following groups of proliferating cells are distinguished: atypical neoplastic histiocytes - large with bubble-shaped or hyperchromatic, often lobulated nuclei containing nucleoli, and basophilic pyrrolinophilic cytoplasm; macrophages with nuclei of various configurations, containing in their cytoplasm numerous erythrocytes as a result of erythrophagocytosis, cellular debris, thrombocytes, hemosiderin and lipid-containing complexes; well-differentiated histiocytes are large oval or elongated cells with eosinophilic cytoplasm and a bubble-shaped nucleus, containing phagocytized erythrocytes and other inclusions. Among the above forms, there are numerous transitional cells. Necrosis is often observed. In addition to histiocytes, the infiltrates contain neutrophilic and eosinophilic granulocytes, plasma cells, lymphocytes, giant cells, often of bizarre shapes, resembling reticulosarcoma cells. Small non-phagocytic cells with pale cytoplasm and hyperchromatic nuclei are identical to the so-called prohistiocytes, although their structure is not clearly defined. In the subcutaneous fat tissue, a picture of panniculitis with focal lipogranulomas is often noted. Histochemically, in many cells, the activity of non-specific esterase is determined diffusely or in the form of granules. Ultrastructurally, specific formations in the form of "rackets" are detected in histiocytes, which can serve as a reliable diagnostic marker of histiocytosis X.

[ 1 ], [ 2 ], [ 3 ]