Case 25 from Dimity McCracken
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A cachectic 65yo woman was presented to her GP with lethargy, fatigue & vague abdominal pain. The GP noticed she had multiple bruises, but the patient explained she had always been clumsy & knocked against furniture frequently. The GP wasn’t convinced so performed quick iSTAT blood test & noticed her Hb 68. He referred the patient to ED.
In ED she was noted to have marked splenomegaly.
Hb 67, WCC 18, plts 83, mild transaminitis on LFT’s.
This is her CT scan: What are the findings? What is the differential diagnosis?
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The CT scan shows:
-marked splenomegaly with an old posterior wedge infarct
-post-contrast low attenuation material in spleen most likely represents haematological malignancy
-there are multiple small para-aortic lymph nodes
Differential Diagnosis for anaemia with thrombocytopaenia, elevated WCC, & splenomegaly with infiltrate:
Haematological malignancy (Primary myelofibrosis) would account for all these findings
Malaria – in which case the anaemia would be more likely to be haemolysis related
Splenomegaly due to hepatic congestion (less likely to have hypodense infiltrations & doesn’t adequately explain bloods)
Gaucher disease (lipid deposition disorder) although it would explain the clinical situation, this patient does not have other features of the condition (usually diagnosed in childhood)
Endocarditis would account for the splenic infarct, but doesn’t adequately explain the infiltration seen on CT scan (since it is not consistent with abscess formation)
NB: this patient’s thrombocytopaenia is likely an “apparent thrombocytopaenia” from hypersplenic sequestration, rather than true reduction in total platelet numbers.
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What is does the Spleen do?
The spleen is a haemopoietic organ which participates in cellular & humoral immunity. It removes aged red cells & bacteria from the circulation, & sequesters platelets.
LITFL’s summary of differential diagnosis of splenomegaly
Radiopaedia also looks at the various causes of splenomegaly, with some amazing associated images.
Myelofibrosis is a myelproliferative disorder where bone marrow is replaced with connective tissue & progressive fibrosis.
Characteristically there is extramedullary haematopoiesis (mostly occurs in the spleen) which accounts for the progressive splenomegaly & anaemia. The platelet count is variable. It is more common in older men, & can transform into leukaemia. There can be associated lymphadenopathy, & hepatomegaly with portal hypertension
Myelofibrosis can be a primary disorder (ie. myeloid metaplasia), or secondary due to marrow replacement from malignancy or toxins (such as toluene or benzene) or significant radiation exposure.
The longterm prognosis for patients with myelofibrosis is poor, with an average survival of 2-3yrs after diagnosis.