Teaching Case

A middle-aged female patient presented with generalised weakness and fatigue for several months. On examination, pallor and hepatosplenomegaly were noted. The rest of the examination findings were within normal limits.

Ultrasonography of the abdomen revealed hepatomegaly with dilatation of the portal and splenic veins. The spleen was grossly enlarged in size (Figure 1). There was thickening of the wall of the right pelvicalyceal system and proximal ureter, without any significant vascularity prompting the suspicion of chronic pyonephrosis initially (Figures 2a, 2b and 2c).

Contrast-enhanced computed tomography (CECT) of the abdomen revealed hepatomegaly and gross splenomegaly. Both the portal and splenic veins were mildly dilated, measuring approx. 15 mm and 11 mm, respectively. The right pelvicalyceal system and proximal ureter exhibited heterogeneously enhancing wall thickening, accompanied by mildly enhancing soft tissue in the perinephric region as well (Figures 3a, 3b, 4a and 4b). On examining the bone window, it was found that the visualised bones demonstrated diffuse sclerosis with coarse trabeculations (Figures 5a and 5b).

Magnetic resonance imaging (MRI) of the spine was done for confirmation, which showed diffuse hypointensity of the visualised axial skeleton on T1W and T2W sequences (Figures 6a, 6b).

Background

Extramedullary haematopoiesis (EMH) typically occurs in the liver, spleen, and paraspinal regions but can affect nearly any organ [1]. In the urinary system, EMH can cause enlarged kidneys, renal failure, and obstruction of the ureters and bladder [2].

Massive splenomegaly can occur in haematological disorders like myeloproliferative disorders (e.g., chronic myeloid leukaemia), myeloid metaplasia and β-thalassemia major, infections (e.g., visceral leishmaniasis, chronic malaria), and infiltrative diseases (e.g., Gaucher’s disease) [3].

Myelofibrosis is marked by bone marrow fibrosis, splenomegaly, and EMH. Abdominal manifestations include hepatosplenomegaly due to EMH, splenic infarcts, lymphadenopathy, and portal hypertension [4].

Clinical Perspective

Patients with EMH often show non-specific signs and symptoms. Massive splenomegaly presents as vague left upper quadrant pain with a palpable spleen [5].

Myelofibrosis mainly affects adults, presenting with weakness, fatigue, and weight loss. It is characterised by splenomegaly, hepatomegaly, and sometimes lymphadenopathy. Laboratory findings typically include moderate normocytic anaemia, teardrop-shaped erythrocytes, anisocytosis, elevated reticulocyte counts, leucocytosis, and immature myeloid cells [4].

Imaging Perspective

The imaging appearance of EMH on CT typically shows heterogeneous, hypovascular soft tissue masses with areas of fat attenuation. On MRI, EMH presents as heterogeneous masses with variable signals on T1W and T2W sequences [6].

In myelofibrosis, imaging typically reveals bone marrow changes like osteosclerosis, especially in the axial skeleton, which is easily seen on CT. MRI shows low signal intensity on T1W and T2W sequences due to fibrous tissue and cellular material replacing normal marrow. STIR sequences and gadolinium-enhanced imaging help assess marrow blood flow and disease severity. Splenomegaly and hepatomegaly with or without liver lesions and splenic infarcts are seen on CT and MRI, which may need differentiation from other conditions [7].

In our case, CECT showed mildly enhancing wall thickening in the pelvicalyceal system and upper ureter, along with mildly enhancing soft tissue in the right perinephric area. The diffuse bone sclerosis and hepatosplenomegaly suggested a haematological disorder, leading to a bone marrow biopsy and peripheral blood smear for further evaluation.

Outcome

The blood smear showed mild anisocytosis with normocytic, normochromic red blood cells, numerous teardrop-shaped cells, and a left shift in the myeloid series. Platelets were normal. Bone marrow analysis revealed atypical megakaryocytes, predominance of myeloid cells, reduced erythroid cells, and grades 3 reticulin and collagen fibrosis, confirming myelofibrosis with osteosclerosis. Ureteroscopy-guided biopsy confirmed that the ureteric wall thickening was due to EMH. Additionally, a liver biopsy also confirmed EMH.

Take Home Message / Teaching Points

Gross splenomegaly requires a thorough workup due to its limited differential diagnoses. For pelvicalyceal and ureteric wall thickening, differential diagnoses include renal lymphoma and organised pyonephrosis. Given that EMH can present in unexpected locations, a comprehensive evaluation is crucial to avoid misdiagnosis.

Written informed patient consent for publication has been obtained.