CASE IS OPEN:  
57 yrs old lady with previous splenectomy due to unclassified histiocytic tumor in 2014(linked case No.561404).  
Persisting anemia and thromocytopenia (after splenectomy)(18).  
Intravenous Ig not effective, eltrombopag and after- romiplastin.  
 
SPLEEN TUMOR (2014) IH: CD4+; CD68+; Lysozyme+; CD1a/S100(-); CD23/CD21(-). Ki67 prolif. activity low <5% (mainly higher on erythroids, scattered histiocytic nuclei).  
 
PET scan:  
LIVER: right lobe: subtotal metabolically active zone SUVmax 11.69.  
Hilus: several nodes SUVmax 7.82.  
All bone marrow: infiltration SUVmax 8.77.  
 
CT scan:  
Kepenų S5/6/8 heterogenous tumor with capsular retraction enlarged up to 81 x 57 mm (previously 59 x 46 mm).  
hilar node up to 26 x 15 mm (previously ~26 x 13 mm.).  
Splenectomy place: ~32x29 mm ir 18x16 mm "splenulae" vs MTS.  
Bone structure effaced with irregular focci.  
 
LIVER BIOPSY: Confluent zones of spindled and pale epithelioid histiocytes with reniform, ovoid, pleomorphic nuclei.  
Not typed fully: CD68+; Ki67 low ~1%; Asm Actin/Desmin/H-caldesmon, CD34/CD31/S100/ALK/STAT6(-).  
 
BONE MARROW:  
a) Bone marrow panhyperplasia (after age) with architectural damage, erythroid hiperplasia/megaloblastic dyserythropoiesis, minimal Fe deposition, TdT+ hematogone excess: reactive changes (B12/Folic deficiency? other?).  
b) Atypical histiocytic infiltration, ~5% BM.  
IH: CD68/CD163/CD4+; CyclinD1+; p53+; S100/CD1a/CD11c(-).  
 
MOLECS (retrospectively from spleen): BRAF mutations not detected.  
BM: SF3B1 not detected in the region R590-G740.  
NGS (solid targeted panel): no significant abberrations detected.  
IgH K L and TCR clonality not detected (in 2014).  
 
DIAGNOSTIC QUESTION: Definite NOSOLOGIC position of disseminated (indolent/low Ki67) histiocytosis (non Langerhans)?