Massive splenomegaly

Question 24.3 from the first paper of 2009 asks the candidate to list three causes of massive splenomegaly. This was a sub-question worth perhaps 3 of the 10 marks, in a 300-mark paper. A perfect answer would have only scored a maximum 1% in the SAQs, or 0.3% to the total of the fellowship exam outcome. It is therefore almost completely meaningless, and the savvy candidate will limit their revision of this topic to the short list of causes, ignoring virtually everything else.

That list:

• Kala Azar (visceral leishmaniasis)
• Chronic malaria (hyper-reactive malarial splenomegaly)
• Chronic tuberculosis
• Chronic schistosomiasis
• Primary splenic lymphoma
• Myelofibrosis
• Chronic myeloid leukaemia (CML)
• Thalassaemia major or intermedia
• Gaucher's disease
• Sarcoidosis
• POEMS syndrome
• Polycythemia vera
• Amyloidosis
• Waldenstrom's macroglobulinaemia
• Haemophagocytic lymphohistiocytosis

Unlike virtually every other sort of megaly, Talley and O'Connor do not offer a list of massive splenomegalies. The best resources I have found for this have been the following articles:

• Luo et al -"Massive splenomegaly" (2008).
• Johnson et al. "Massive splenomegaly." (1989)
• NEJM Case Reports: Noopur e al (2001), and Wyler et al (1994)

The italicised entries in the list above come from the NEJM case reports, where these conditions are listed along with other causes of massive splenomegaly, but without any explanation of the association, and without any references.

Causes of hepatosplenomegaly were asked for in Question 30.3 from the first paper of 2017. There are many shared causes:

Also, Hoffbrand's Essential Haematology has a table with the causes of splenomegaly somewhere in chapter 10. The causes of massive splenomegaly are also  briefly discussed in this tropical disease oriented article. The college answer to Question 24.3 is presumably derived from this paper or something very much like it; however the college only list CML, myelofibrosis, chronic malaria and KalaAzar.

Beyond the boring list of diseases associated with a huge spleen lurks the debate regarding what precisely qualifies as "massive". One 1989 paper takes "massive" to mean "drained weight in excess of 1kg",which most people would agree is pretty big. In spite of the obvious difficulty of assessing the dry drained weight of a spleen in vivo, this definition seems to be consistent across such sources of enlightenment as Medscape eMedicine and Wikipedia. A slightly more workable definition of "massive splenomegaly" comes from Eric Poulin, even though he used the word "severe" instead - in his view anything more than 20cm in any dimension was a real cause for concern, and therefore merited a strong superlative. Those abovementioned NEJM case reports defined massive splenomegaly in terms of a spleen that reaches to the pelvis or which has crossed the midline into the right side of the abdomen.