PA H9 | Spleen Disorders — Glossary

A myeloproliferative neoplasm driven by BCR-ABL1 fusion; neoplastic myeloid progenitors home to and proliferate in the spleen, causing one of the largest spleens in haematological disease.

Production of blood cells outside the bone marrow; occurs in the spleen (and liver) when the marrow is replaced or fibrosed, as in myelofibrosis and thalassaemia major.

The triad of rheumatoid arthritis, splenomegaly, and neutropenia; IgG-coated neutrophils are sequestered and destroyed in the spleen, predisposing to recurrent infections.

Chronic congestive splenomegaly in which repeated episodes of congestion and small haemorrhage lead to fibrous thickening of sinusoidal walls; the end-stage of long-standing portal hypertension.

Small foci of organised haemorrhage containing haemosiderin and calcium within the spleen in chronic congestive splenomegaly; appear as signal voids on MRI T2*-weighted sequences.

Autosomal recessive lysosomal storage disorder due to glucocerebrosidase deficiency; glucocerebroside accumulates in macrophages (Gaucher cells with 'crumpled tissue paper' cytoplasm) causing massive splenomegaly and bone marrow infiltration.

Insoluble crystalline byproduct of haemoglobin degradation by Plasmodium species; deposited in splenic macrophages in chronic malaria, imparting a dark brown colour to the spleen.

Residual nuclear chromatin fragments in RBCs, normally pitted out by the spleen; their presence on blood film is pathognomonic of a hyposplenic or asplenic state.

A functional state defined by four criteria: splenomegaly, peripheral cytopenias, hypercellular bone marrow, and correction of cytopenias by splenectomy.

Infection by Leishmania donovani; amastigotes multiply within red pulp macrophages producing massive splenomegaly and pancytopenia; endemic in Bihar, Jharkhand, and West Bengal.

Diffuse amyloid deposits in the red pulp sinusoids giving the spleen a large, firm, waxy, pale appearance on gross examination; contrasted with sago spleen (follicular deposits).

Splenomegaly extending to or beyond the umbilicus, or spleen weight >1 kg; caused classically by CML, myelofibrosis, kala-azar, malaria, Gaucher disease, or thalassaemia major.

Progressive replacement of marrow by fibrosis, driving haematopoiesis to the spleen (myeloid metaplasia); presents with massive splenomegaly, leukoerythroblastic blood film, and teardrop cells.

A fulminant, potentially fatal septicaemia caused by encapsulated bacteria (classically S. pneumoniae, H. influenzae, N. meningitidis) in patients without a functional spleen; mortality 50–70% once established.

A cuff of T lymphocytes surrounding the central arteriole of the white pulp; the primary T-cell zone of the spleen, analogous to the paracortex of a lymph node.

The splenic function of removing intra-erythrocytic inclusions (Howell-Jolly bodies, Heinz bodies, malarial parasites) while returning the viable RBC to circulation.

The filtration compartment of the spleen (~75% of parenchyma) consisting of sinuses lined by littoral cells and cords of Billroth; removes aged or abnormal RBCs and pits intra-erythrocytic inclusions.

Pattern of splenic amyloidosis in which AA or AL amyloid deposits are confined to the white pulp follicles, giving the cut surface a granular, tapioca-like appearance.

Enlargement of the spleen beyond its normal weight of 150–200 g; clinically palpable below the left costal margin, implying weight >400 g.

Red blood cells with a central area of haemoglobin surrounded by a pallor zone and a dense peripheral ring, resembling a shooting target; appear after splenectomy due to excess membrane relative to cell volume, and in liver disease, thalassaemia, and HbC.

The lymphoid compartment of the spleen (~25%) arranged around the periarteriolar lymphoid sheath (T cells) with B-cell follicles; responsible for IgM synthesis and opsonisation of encapsulated bacteria.