Systemic non-Langerhans cell histiocytosis

Systemic non-Langerhans cell histiocytosis N.O.S. (Not otherwise specified). Liver biopsy. Etiology unknown.

Clinical synopsis

 pancytopenia
 posterio mediastinal tumor (tumor of the costo-vertebral angle) (T3-T6)
 bone marrow fibrosis (myelofibrosis)

Digital slides

Biopsy 1: Bone marrow biopsy

 H&E: NCK8-180 (ICSFramework)

Biopsy 1: Posterior mediastinal tumor

 H&E : NCK8-181 (ICSFramework)
 CD163 : NCK8-183 (ICSFramework)
 CD68 : NCK8-182 (ICSFramework)

Biopsy 3: Liver biopsy

 H&E: NCK8-179 (ICSFramework)
 Smooth Muscle Actin (SMA): NCK8-178 (ICSFramework)

Pathological synopsis

 non-Langerhans cell histiocytosis
 histiocytic infiltration CD68+, CD163+, CD1a-, S100-
 ALK- immunochemistry
 no ALK rearrangement by FISH

Differential diagnosis

 systemic juvenile xanthogranuloma ?
 systemic non-Langerhans cell histiocytosis (NOS) ?
 ALK- inflammatory myofibroblastic tumor (inflammatory pseudotumor)