ClinicalRadiology(1992) 46, 281-283
Case Report: Chronic Spinal Cord Compression From Extramedullary Haematopoiesis in Thalassaemia- MRI Findings L. P A N T O N G R A G - B R O W N
and N. SUWANWELA
Department of Radiology, Chulalongkorn University Hospital, Bangkok, Thailand J
A 27-year-old-man with fl-thalassaemia/HbE presented with signs and symptoms of spinal cord compression due to epidurai extramedullary haematopoiesis. Magnetic resonance images demonstrated spinal cord constriction and atrophy suggesting that the disease process was longstanding. On transverse T2-weighted images, high signal intensity was observed within the spinal cord suggestive of post-compressive spinal cord myelomalaeia or gliosis. P a n t o n g r a g B r o w n , L. & S u w a n w e l a , N . (1992). Clinical Radiology 46, 2 8 1 - 2 8 3 . C a s e R e p o r t : C h r o n i c S p i n a l C o r d C o m p r e s s i o n f r o m E x t r a m e d u l l a r y H a e m a t o p o i e s i s in T h a l a s s a e m i a - M R I Findings
T h e t h a l a s s a e m i a s y n d r o m e s are a g r o u p o f h e r e d i t a r y d i s o r d e r s in w h i c h t h e r e is defective synthesis o f the g l o b i n c h a i n ( s ) o f h a e m o g l o b i n [1]. T h e n e t result is a c h r o n i c a n a e m i a w h i c h c a u s e s e x p a n s i o n o f red m a r r o w spaces a n d s e c o n d a r y b o n y changes. E x t r a m e d u l l a r y h a e m a t o p o i e s i s ( E M H ) is a c o m p e n s a t o r y p h e n o m e n o n e n c o u n t e r e d in this c o n d i t i o n . A l t h o u g h t h o r a c i c p a r a spinal E M H is c o m m o n i n t h a l a s s a e m i a , o n l y a s m a l l n u m b e r o f cases p r e s e n t w i t h s p i n a l c o r d c o m p r e s s i o n d u e to e p i d u r a l h a e m a t o p o i e t i c tissue [2,3]. M a g n e t i c r e s o n a n c e i m a g i n g ( M R I ) has b e c o m e a n i m p o r t a n t d i a g n o s t i c t e c h n i q u e in the a s s e s s m e n t o f diseases o f the s p i n a l c o r d . M R I f i n d i n g s o f e p i d u r a l E M H in t h a l a s s a e m i a h a v e b e e n r e p o r t e d [4]. T h e M R I demonstration of spinal cord atrophy and intrinsic spinal cord signal a b n o r m a l i t y d u e to c h r o n i c c o r d c o m p r e s s i o n have n o t , h o w e v e r , b e e n d e s c r i b e d previously. W e r e p o r t a case w h e r e those f i n d i n g s were o b s e r v e d a n d c o n t r i b u t e d to a m o r e c o m p l e t e u n d e r s t a n d i n g o f the disease process.
CASE REPORT A 27-year-old man had a history of weakness and impaired sensation of both lower extremities for 3 years, increasing over the last 3 months. He described jaundice and anaemia since childhood. On physical examination, he was pale and jaundiced. His face had the characteristic thalassaemic appearance. Liver and spleen were enlarged. Neurological examination disclosed weakness of the lower extremities with decreased muscle power (grade 4/5) bilaterally. Loss of sensation and proprioception at about the L1 level and below was noted. Deep tendon reflexes of both lower limbs were normal, but Babinski's sign was positive bilaterally. His haemoglobin was 5.7 gin% and the blood smear showed moderately hypochromic and anisopoikilocytic red blood cell morphology. Haemoglobin electrophoresis revealed 62% HbE and 18% HbF. These findings were consistent with his diagnosis as a compound flthalassaemia/HbE heterozygote. Plain films of the chest and thoracic spine showed bilateral lobulated, paravertebral soft-tissue masses. Osteoporotic ribs with expansion of the medullary cavities and thinning of the cortices were seen. Accentuation of trabeculae of the vertebral bodies was also observed. A Correspondence to: Dr Linda Pantongrag-Brown, Department of Radiology, Chulalongkorn University Hospital, Rama IV Road, Bangkok 10330, Thailand.
Fig. 1 - C T post-myelogram, at T7 level, shows constriction of the subarachnoid space and anterior displacement of the spinal cord by an epidural soft-tissue mass (E). Note also the expanded posterior ribs and paravertebral masses (P). myelogram was performed, but the lesion was not well delineated due to technical error. However, there was no evidence of CSF obstruction. Computed tomography (CT) of the spine following myelography showed anterior displacement of the spinal cord by an epidural softtissue mass (Fig. 1), from the middle to the lower thoracic levels of the spine. MRI of the spinal column was performed with sagittal spin echo T1weighted, and sagittal and transverse gradient echo T2-weighted images on a 0.5 Tesla system (MR MAX, GE) (Figs 2 and 3). On both T1- and T2-weighted images, the epidural mass showed intermediate signal intensity, slightly higher than the bone marrow signal within vertebral bodies. The spinal cord decreased in diameter from T6 to T9, suggesting mass-related atrophy. On transverse T2weighted images at the level of the atrophic cord, there was a small area of high signal intensity within the spinal cord suggestive of postcompressive spinal cord myelomalacia (Fig. 3). Based upon the clinical information and the findings on imaging, epidural EMH was diagnosed. Radiation therapy (20 Gy) was administered in 10 fractions resulting in partial clinical improvement. DISCUSSION I n T h a i l a n d , ~- a n d f l - t h a l a s s a e m i a , a n d H b E are c o m m o n [5]. C o m p l i c a t i o n s a s s o c i a t e d w i t h t h a l a s s a e m i a
282
CLINICAL RADIOLOGY
(a)
(b)
Fig. 2 - Sagittal spin echo T1-weighted (SE 324/25) (a) and T2-weighted gradient echo (GE 700/25/flip angle 30 °) (b) M R images showing evidence of a long epidural mass extending from T4 T11 levels (arrows). The signal intensity of the mass is slightly higher than that of the adjacent bone marrow within vertebral bodies. Note also the small size of the spinal cord from T6-T9 suggestive of atrophy due to the chronicity of the disease.
include anaemia, iron overload and increased streptococcal infection [2]. E M H is a compensatory phenomenon that may occur when there is chronic overstimulation of red cell production or encroachment on bone marrow spaces [6]. E M H usually forms a soft, deep red mass which resembles a haematoma on its cut surface. Histologically, these tissues are composed of all haematopoietic elements, i.e. myeloid, erythroid and megakaryocytic [7]. Usual sites of E M H are liver, spleen, and lymph nodes [8,9]. Hepatosplenomegaly, as in this case, may represent a source of EMH. Unusual locations of E M H include the thorax, retroperitoneal tissue, adrenal gland, kidney, thymus, dura, breast, prostate glafld and epididymis [8,10]. Among all aetiologies of intrathoracic paraspinal EMH, thalassaemia is the most common [7]. However, spinal cord compression as a complication of paraspinal E M H is rare [3]. There are two hypotheses to explain the origin of
epidural EMH. The first is direct extension into the epidural space by bone marrow extruding from posterior ribs or vertebral bodies [11]. The second is that the embryonic cell rests within the epidural space have been transformed into haematopoietic tissue [10]. In our case, there was an anatomical association between the locations of thoracic paravertebral and epidural masses, as well as expansion of the adjacent ribs, thus favouring the former hypothesis. Given the appropriate clinical setting, findings on conventional radiography and CT scanning are usually sufficient to diagnose spinal cord compression due to EMH. MRI, due to its multiplanar capability, contributes further by accurately delineating the extent of the lesion and thereby helps to localize the optimal field if radiation therapy is to be given. Histological proof of diagnosis requires invasive procedures which are very hazardous because of the highly vascular nature of
MRI OF CHRONIC SPINAL CORD COMPRESSION IN THALASSAEMIA
283
ing more individuals with thalassaemia/haemoglobinopathy to the West. Awareness of this complication is necessary if it is to be recognized and treated promptly.
REFERENCES
Fig. 3 Transverse gradient echo T2-weighted image (GE 1714/25ifli p angle 30°), at T7 level, corresponding to the level in Fig. 1, shows a small area of high signal intensity within the spinal cord (arrow). Note also epidural (E) and paravertebral (P) masses.
extramedullary haematopoietic masses [t2]. Diagnosis based on the MRI findings allowed these procedures to be avoided in our case. The MRI appearances in this case were similar to those described by previous workers [4]. The mass was of intermediate signal intensity, slightly higher than the adjacent marrow within vertebral bodies in both T1- and T2-weighted images. Transverse T2-weighted images demonstrated high signal intensity within an atrophic spinal cord. This high signal intensity is suggestive of myelomalacia or cord gtiosis secondary to the effects of long-standing compression [13]. MRI is becoming the procedure of choice for spinal imaging, particularly in developed countries where it is more likely to be available. Despite this, we are aware of only one report in the English literature describing MRI imaging of epidural EMH [4]. Part of the explanation for this is probably that Southeast Asian and Mediterranean countries where there is a high incidence of thalassaemia are areas where access to MRI is limited. Nevertheless, migration of refugees from Southeast Asia is now bring-
1 Weatherall DJ. Disorders of the synthesis or function of haemoglobin. In: Weatherall D J, Ledingham JGG & Warrell DA, eds. Oxford textbook of medicine, Vol. II, 2nd ed. New York: Oxford University Press, 19.108 19.130. 2 Issaragrisil S, Piankijagum A, Wasi P. Spinal cord compression in thalassemia: report of 12 cases and recommendation for treatment. Archives of Internal Medicine 1981;141:1033 1036. 3 Papavasiliou C, Gouliamos A, Andreou J. The marrow heterotopia / in thalassemia. European Journal of Radiology 1986;6:92 96. 4 Papavasiliou C, Goulimos A, Vlahos L, Trakadas S, Kalovidouris A, Pouliades GR. CT and MRI of symptomatic spinal involvement by extramedullary haematopoiesis. Clinical Radiology 1990;42:9192. 5 Wasi P, Na-Nakorn S, Suingdumromg A. Studies of the distribution of haemoglobin E, thalassemia and glucose-6-phosphatedehydrogenase deficiency in North-eastern Thailand. Nature 1967;214:501502. 6 Jackson A, Burton IE. Retroperitoneal mass and spinal cord compression due to extramedullary haematopoiesis in polycythemia rubra vera. British Journal of Radiology 1989;62:944-947. 7 Verani R, Olson J, Moake JL. Intrathoracic extramedullary hematopoiesis: report of a case in a patient with sickle-cell disease-flthalassemia. American Journal of Clinical Pathology 1980;73:133 137. 8 Close S, Taira Y, Cleveland DA. Spinal cord compression due to extramedullary hematopoiesis. American Journal of Medicine 1958; 48:421-427. 9 Shaver RW, Clore FC. Extramedullary hematopoiesis in myeloid metaplasia. American Journal of Roentgenology 1981;137:874 876. 10 Abbassioun K, Amir-Jamshidi A. Curable paraplegia due to extradural hematopoietic tissue in thalassemia. Neurosurgery 1982;11:804 807. 1t Lawson JP, Ablow RC, Pearson HA. The ribs in thalassemia. II. The pathogenesis of the changes. Radiology 1981;140:673 679. 12 Sorsdahl OS, Taylor PE, Noyes WD. Extramedullary hematopoiesis, mediastinal masses, and spinal cord compression. Journal of the American Medical Association 1964; 189:343-347. 13 Takahashi M, Sakamoto Y, Miyawaki M, Bussaka H. Increased MR signal intensity secondary to chronic cervical cord compression. Neuroradiology 1987;29:550 556.
Case Report: Chronic Spinal Cord Compression From Extramedullary Haematopoiesis in Thalassaemia- MRI Findings L. P A N T O N G R A G - B R O W N
and N. SUWANWELA
Department of Radiology, Chulalongkorn University Hospital, Bangkok, Thailand J
A 27-year-old-man with fl-thalassaemia/HbE presented with signs and symptoms of spinal cord compression due to epidurai extramedullary haematopoiesis. Magnetic resonance images demonstrated spinal cord constriction and atrophy suggesting that the disease process was longstanding. On transverse T2-weighted images, high signal intensity was observed within the spinal cord suggestive of post-compressive spinal cord myelomalaeia or gliosis. P a n t o n g r a g B r o w n , L. & S u w a n w e l a , N . (1992). Clinical Radiology 46, 2 8 1 - 2 8 3 . C a s e R e p o r t : C h r o n i c S p i n a l C o r d C o m p r e s s i o n f r o m E x t r a m e d u l l a r y H a e m a t o p o i e s i s in T h a l a s s a e m i a - M R I Findings
T h e t h a l a s s a e m i a s y n d r o m e s are a g r o u p o f h e r e d i t a r y d i s o r d e r s in w h i c h t h e r e is defective synthesis o f the g l o b i n c h a i n ( s ) o f h a e m o g l o b i n [1]. T h e n e t result is a c h r o n i c a n a e m i a w h i c h c a u s e s e x p a n s i o n o f red m a r r o w spaces a n d s e c o n d a r y b o n y changes. E x t r a m e d u l l a r y h a e m a t o p o i e s i s ( E M H ) is a c o m p e n s a t o r y p h e n o m e n o n e n c o u n t e r e d in this c o n d i t i o n . A l t h o u g h t h o r a c i c p a r a spinal E M H is c o m m o n i n t h a l a s s a e m i a , o n l y a s m a l l n u m b e r o f cases p r e s e n t w i t h s p i n a l c o r d c o m p r e s s i o n d u e to e p i d u r a l h a e m a t o p o i e t i c tissue [2,3]. M a g n e t i c r e s o n a n c e i m a g i n g ( M R I ) has b e c o m e a n i m p o r t a n t d i a g n o s t i c t e c h n i q u e in the a s s e s s m e n t o f diseases o f the s p i n a l c o r d . M R I f i n d i n g s o f e p i d u r a l E M H in t h a l a s s a e m i a h a v e b e e n r e p o r t e d [4]. T h e M R I demonstration of spinal cord atrophy and intrinsic spinal cord signal a b n o r m a l i t y d u e to c h r o n i c c o r d c o m p r e s s i o n have n o t , h o w e v e r , b e e n d e s c r i b e d previously. W e r e p o r t a case w h e r e those f i n d i n g s were o b s e r v e d a n d c o n t r i b u t e d to a m o r e c o m p l e t e u n d e r s t a n d i n g o f the disease process.
CASE REPORT A 27-year-old man had a history of weakness and impaired sensation of both lower extremities for 3 years, increasing over the last 3 months. He described jaundice and anaemia since childhood. On physical examination, he was pale and jaundiced. His face had the characteristic thalassaemic appearance. Liver and spleen were enlarged. Neurological examination disclosed weakness of the lower extremities with decreased muscle power (grade 4/5) bilaterally. Loss of sensation and proprioception at about the L1 level and below was noted. Deep tendon reflexes of both lower limbs were normal, but Babinski's sign was positive bilaterally. His haemoglobin was 5.7 gin% and the blood smear showed moderately hypochromic and anisopoikilocytic red blood cell morphology. Haemoglobin electrophoresis revealed 62% HbE and 18% HbF. These findings were consistent with his diagnosis as a compound flthalassaemia/HbE heterozygote. Plain films of the chest and thoracic spine showed bilateral lobulated, paravertebral soft-tissue masses. Osteoporotic ribs with expansion of the medullary cavities and thinning of the cortices were seen. Accentuation of trabeculae of the vertebral bodies was also observed. A Correspondence to: Dr Linda Pantongrag-Brown, Department of Radiology, Chulalongkorn University Hospital, Rama IV Road, Bangkok 10330, Thailand.
Fig. 1 - C T post-myelogram, at T7 level, shows constriction of the subarachnoid space and anterior displacement of the spinal cord by an epidural soft-tissue mass (E). Note also the expanded posterior ribs and paravertebral masses (P). myelogram was performed, but the lesion was not well delineated due to technical error. However, there was no evidence of CSF obstruction. Computed tomography (CT) of the spine following myelography showed anterior displacement of the spinal cord by an epidural softtissue mass (Fig. 1), from the middle to the lower thoracic levels of the spine. MRI of the spinal column was performed with sagittal spin echo T1weighted, and sagittal and transverse gradient echo T2-weighted images on a 0.5 Tesla system (MR MAX, GE) (Figs 2 and 3). On both T1- and T2-weighted images, the epidural mass showed intermediate signal intensity, slightly higher than the bone marrow signal within vertebral bodies. The spinal cord decreased in diameter from T6 to T9, suggesting mass-related atrophy. On transverse T2weighted images at the level of the atrophic cord, there was a small area of high signal intensity within the spinal cord suggestive of postcompressive spinal cord myelomalacia (Fig. 3). Based upon the clinical information and the findings on imaging, epidural EMH was diagnosed. Radiation therapy (20 Gy) was administered in 10 fractions resulting in partial clinical improvement. DISCUSSION I n T h a i l a n d , ~- a n d f l - t h a l a s s a e m i a , a n d H b E are c o m m o n [5]. C o m p l i c a t i o n s a s s o c i a t e d w i t h t h a l a s s a e m i a
282
CLINICAL RADIOLOGY
(a)
(b)
Fig. 2 - Sagittal spin echo T1-weighted (SE 324/25) (a) and T2-weighted gradient echo (GE 700/25/flip angle 30 °) (b) M R images showing evidence of a long epidural mass extending from T4 T11 levels (arrows). The signal intensity of the mass is slightly higher than that of the adjacent bone marrow within vertebral bodies. Note also the small size of the spinal cord from T6-T9 suggestive of atrophy due to the chronicity of the disease.
include anaemia, iron overload and increased streptococcal infection [2]. E M H is a compensatory phenomenon that may occur when there is chronic overstimulation of red cell production or encroachment on bone marrow spaces [6]. E M H usually forms a soft, deep red mass which resembles a haematoma on its cut surface. Histologically, these tissues are composed of all haematopoietic elements, i.e. myeloid, erythroid and megakaryocytic [7]. Usual sites of E M H are liver, spleen, and lymph nodes [8,9]. Hepatosplenomegaly, as in this case, may represent a source of EMH. Unusual locations of E M H include the thorax, retroperitoneal tissue, adrenal gland, kidney, thymus, dura, breast, prostate glafld and epididymis [8,10]. Among all aetiologies of intrathoracic paraspinal EMH, thalassaemia is the most common [7]. However, spinal cord compression as a complication of paraspinal E M H is rare [3]. There are two hypotheses to explain the origin of
epidural EMH. The first is direct extension into the epidural space by bone marrow extruding from posterior ribs or vertebral bodies [11]. The second is that the embryonic cell rests within the epidural space have been transformed into haematopoietic tissue [10]. In our case, there was an anatomical association between the locations of thoracic paravertebral and epidural masses, as well as expansion of the adjacent ribs, thus favouring the former hypothesis. Given the appropriate clinical setting, findings on conventional radiography and CT scanning are usually sufficient to diagnose spinal cord compression due to EMH. MRI, due to its multiplanar capability, contributes further by accurately delineating the extent of the lesion and thereby helps to localize the optimal field if radiation therapy is to be given. Histological proof of diagnosis requires invasive procedures which are very hazardous because of the highly vascular nature of
MRI OF CHRONIC SPINAL CORD COMPRESSION IN THALASSAEMIA
283
ing more individuals with thalassaemia/haemoglobinopathy to the West. Awareness of this complication is necessary if it is to be recognized and treated promptly.
REFERENCES
Fig. 3 Transverse gradient echo T2-weighted image (GE 1714/25ifli p angle 30°), at T7 level, corresponding to the level in Fig. 1, shows a small area of high signal intensity within the spinal cord (arrow). Note also epidural (E) and paravertebral (P) masses.
extramedullary haematopoietic masses [t2]. Diagnosis based on the MRI findings allowed these procedures to be avoided in our case. The MRI appearances in this case were similar to those described by previous workers [4]. The mass was of intermediate signal intensity, slightly higher than the adjacent marrow within vertebral bodies in both T1- and T2-weighted images. Transverse T2-weighted images demonstrated high signal intensity within an atrophic spinal cord. This high signal intensity is suggestive of myelomalacia or cord gtiosis secondary to the effects of long-standing compression [13]. MRI is becoming the procedure of choice for spinal imaging, particularly in developed countries where it is more likely to be available. Despite this, we are aware of only one report in the English literature describing MRI imaging of epidural EMH [4]. Part of the explanation for this is probably that Southeast Asian and Mediterranean countries where there is a high incidence of thalassaemia are areas where access to MRI is limited. Nevertheless, migration of refugees from Southeast Asia is now bring-
1 Weatherall DJ. Disorders of the synthesis or function of haemoglobin. In: Weatherall D J, Ledingham JGG & Warrell DA, eds. Oxford textbook of medicine, Vol. II, 2nd ed. New York: Oxford University Press, 19.108 19.130. 2 Issaragrisil S, Piankijagum A, Wasi P. Spinal cord compression in thalassemia: report of 12 cases and recommendation for treatment. Archives of Internal Medicine 1981;141:1033 1036. 3 Papavasiliou C, Gouliamos A, Andreou J. The marrow heterotopia / in thalassemia. European Journal of Radiology 1986;6:92 96. 4 Papavasiliou C, Goulimos A, Vlahos L, Trakadas S, Kalovidouris A, Pouliades GR. CT and MRI of symptomatic spinal involvement by extramedullary haematopoiesis. Clinical Radiology 1990;42:9192. 5 Wasi P, Na-Nakorn S, Suingdumromg A. Studies of the distribution of haemoglobin E, thalassemia and glucose-6-phosphatedehydrogenase deficiency in North-eastern Thailand. Nature 1967;214:501502. 6 Jackson A, Burton IE. Retroperitoneal mass and spinal cord compression due to extramedullary haematopoiesis in polycythemia rubra vera. British Journal of Radiology 1989;62:944-947. 7 Verani R, Olson J, Moake JL. Intrathoracic extramedullary hematopoiesis: report of a case in a patient with sickle-cell disease-flthalassemia. American Journal of Clinical Pathology 1980;73:133 137. 8 Close S, Taira Y, Cleveland DA. Spinal cord compression due to extramedullary hematopoiesis. American Journal of Medicine 1958; 48:421-427. 9 Shaver RW, Clore FC. Extramedullary hematopoiesis in myeloid metaplasia. American Journal of Roentgenology 1981;137:874 876. 10 Abbassioun K, Amir-Jamshidi A. Curable paraplegia due to extradural hematopoietic tissue in thalassemia. Neurosurgery 1982;11:804 807. 1t Lawson JP, Ablow RC, Pearson HA. The ribs in thalassemia. II. The pathogenesis of the changes. Radiology 1981;140:673 679. 12 Sorsdahl OS, Taylor PE, Noyes WD. Extramedullary hematopoiesis, mediastinal masses, and spinal cord compression. Journal of the American Medical Association 1964; 189:343-347. 13 Takahashi M, Sakamoto Y, Miyawaki M, Bussaka H. Increased MR signal intensity secondary to chronic cervical cord compression. Neuroradiology 1987;29:550 556.
