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Paravertebral extramedullary haemopoiesis associated with pyruvate kinase deficiency
A 62-year-old woman with known pyruvate kinase deficiency and previous splenectomy in early adulthood was investigated for breathlessness. A chest radiograph demonstrated a right retro-cardiac mass and computed tomography/magnetic resonance imaging scans confirmed a 56 · 37 · 60 mm heterogeneous soft tissue mass in the right paravertebral region at the T9/T10 level (top and bottom). The provisional diagnosis was of a neurogenic tumour and surgical excision was planned. Her full blood count at the time was as follows: haemoglobin concentration 101 g/l, white cell count 10Æ76 · 109/l, platelet count 660 · 109/l and mean cell volume 105Æ9 fl. Bilirubin was 28 lmol/l. She had been transfusion independent. At thoracotomy the mass appeared very vascular and adherent to the ribs and vertebra without bony erosion and with no involvement of nerve roots. The mass was completely excised at thoracotomy and microscopically was composed of varying proportions of mature adipocytes mixed with haemopoietic tissue with normal maturation. Extramedullary haemopoiesis is typically (>90% of cases) found in the liver and ª 2009 Blackwell Publishing Ltd, British Journal of Haematology, 147, 275
spleen in the context of myelofibrosis or thalassaemia but can occur rarely in the paravertebral area, central nervous system, eye, lymph nodes, myocardium, lung and pleura. There have been four previous reports of extramedullary haemopoiesis affecting the paravertebral area associated with pyruvate kinase deficiency with one case leading to spinal cord compression. Rupert Hipkins1 Joyce Thompson2 Prabha Naidoo3 Ehab Bishay4 Madava Djearaman5 Guy Pratt1,6 Departments of 1Haematology, 2Oncology, 3Histopathology, 4Thoracic surgery, 5Radiology, Birmingham Heartlands Hospital, Birmingham, and 6Institute for Cancer Studies, University of Birmingham, Birmingham, UK. E-mail:
[email protected]
First published online 13 February 2009 doi:10.1111/j.1365-2141.2009.07621.x
