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)?

tzankov 2019-04-05 14:06

very difficult case. the liver biopsy most probably represents dissemination of the splenic tumor. the xanthomatous cells in the bone marrow may belong to the clone, but may be also reactive.     Is there a history of recent myelotoxic exposition?   Peripheral blood values?   Dysplasia on the aspirate (note that the CD34+ blast equivalents seem to be increased)?   Has the splenic tumor been studied for EBER?   Were all MAPK-pathway compounds covered by the NGS panel?

ugnius 2019-04-05 15:44

EBER(-). NGS full gene list appended. It was decided treat with Cytosar (?).