www. centauro. it
The Neuroradiology Journal 20: 359-363, 2007
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis. A Case Report N. BULAKBASI, M. KOCAOGLU, I. KARADEMIR, B. USTUNSOZ Radiology Deparment, Gulhane Military Medical Academy; Etlik, Ankara, Turkey
Key words: systemic mastocytosis, central nervous system involvement, computed tomography, magnetic resonance imaging
SUMMARY – Central nervous system involvement in systemic mastocytosis (SM) is very rare. This case report describes the computed tomography and magnetic resonance (MR) imaging findings of central nervous system involvement in a patient with isolated bone marrow mastocystosis. Bone marrow infiltration in SM caused cranial nerve dysfunction and meningeal irritation secondary to narrowing of cranial apertures and meningeal involvement, respectively. MR imaging is the modality of choice in both detection and follow-up of SM and also useful for differential diagnosis and detection of complications.
Introduction
Case Report
Mastocytosis is a rare heterogeneous group of disorders characterized by abnormal proliferation and accumulation of mast cells in one (skin) or more organ systems (bone marrow, liver, spleen, gastrointestinal mucosa and lymph nodes) 1. According to the updated consensus classification of WHO, mastocytosis is classified into seven clinical categories of disease on the basis of pathologic findings, clinical presentation, and prognosis 2,3. These subgroups include (a) cutaneous mastocytosis (CM), (b) indolent systemic mastocytosis (SM), (c) SM with an associated clonal hematologic none mast cell lineage disease, (d) aggressive SM, (e) mast cell leukemia, (f ) mast cell sarcoma, and (g) extracutaneous mastocytoma. The WHO classification includes criteria for the differentiation of SM and CM both from each other and from the other myelomastocytic disorders 2,3. Isolated bone-marrow mastocytosis is a subgroup of indolent SM in which mediator-related symptoms are not recorded as frequently as in other subtypes of mastocytosis 4. This case report describes the magnetic resonance (MR) imaging findings of central nervous system involvement in a patient with isolated bone marrow mastocytosis.
A 42-year-old man with clinical and pathological diagnosis of isolated bone marrow mastocystosis was examined by computed tomography (CT) and MR imaging because of progressive blurred vision, numbness on different facial areas, mild meningeal irritation findings and back pain. CT images were obtained with a helical CT scanner (GE Hispeed CT/i, Milwaukee, USA) with 120 kV and 210 mAs, 25 cm FOV and contiguous 5 mm slices from neck to vertex covering the whole face and cranium. All MR measurements were performed on a 1.5 T whole-body MR system (The New Intera Nova; Philips Medical Systems, Best, the Netherlands) using a standard quadrature head and spine coils. For routine brain examination, axial T1-weighted (583/15 ms; 1 excitation) spinecho, T2-weighted (2295/90 ms; 2 excitations) spin-echo, and fast fluid-attenuated inversion recovery (FLAIR) (8000/100/2000 ms; 1 excitation) images were obtained using 5-mm section thickness with 1-mm intersection gap, 220 × 220 mm field of view, and 256 × 256 matrix size. Contrast enhanced T1-weighted spin-echo images were also obtained in the three orthogonal planes following intravenous administra359
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis
A
B
C
D
N. Bulakbasi
Figure 1 A 42-year-old man with isolated bone marrow mastocytosis. A,B) Axial CT images through skull base A) and lateral ventricular B) levels show prominent bone marrow enlargement and cortical thinning. C) Axial T1-weighted image at the level of skull base demonstrates low signal of infiltrated bone marrow. Lateral wall of left orbita is also involved together with the temporal and intracranial surfaces of sphenoid bone. Subperiostal soft tissues are seen in the orbita and around of the ala major. D) Axial T2-weighted images from the skull base show widespread high signal intensity due to mastocyte infiltration, which causes external compression to transverse sinuses (arrowheads). Fluid levels in both middle ear and mastoid cells (arrows) are also noted due to obliteration of both Eustachian tubes. E, F) Postcontrast T1-weighted axial (E) and coronal (F) images imply significant contrast enhancement of infiltrated bone marrow. Bone marrow enlargement causes encasement of optic foramens (small arrows) and cavernous sinuses (arrowheads). Note bilateral meningeal thickening and enhancement (large arrows). The lateral wall of the left orbita is also involved together with the temporal and intracranial surfaces of sphenoid bone. Subperiostal soft tissues are seen in the orbita and around the ala major. G, H) Sagittal T1-weighted (G) and STIR(H) images of the cervical spine show diffuse bone marrow involvement causing diffuse low signal on T1 and high signal on STIR images. Note the biopsy defect in the upper thoracic region (arrow).
360
www. centauro. it
The Neuroradiology Journal 20: 359-363, 2007
E
F
G
H
361
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis
tion of gadodiamid at a dose of 0.2 mmol/kg. For spine MR study, sagittal and axial short tau inversion recovery (STIR, TR/TE/TI 2500/20/150 ms), pre- and post-contrast T1 (TR/TE 600/15 ms) weighted images were obtained using 3mm section thickness with 1 mm intersection gap, 275 × 100 mm field of view, and 256 × 256 matrix size. Widespread bone marrow involvement in skull base, both orbit and calvarium caused bony enlargement and cortical thinning on CT scans (figure 1 A,B). Infiltrated bone morrow showed heterogeneous low signal intensity on T1- (figure 1 C) and high signal on T2-weighted (figure 1 D) images with heterogeneous enhancement (figure 1 E,F). Widespread meningeal thickening and enhancement was also noted in the adjacent dural surface (figure 1 E). Bone marrow involvement of sphenoid bone caused encasement of both cavernous sinuses (figure 1 E-F). On spinal images extensive bone marrow involvement of vertebral bodies was detected without prominent enlargement or destruction (figure 1 G.H). Discussion Bone marrow infiltration of the axial skeleton is a well-known manifestation of SM that occurs in 79% of patients and is commonly asymptomatic, but it may cause pain, tenderness or pathological fractures, mostly in the spine 5,6. Bone marrow involvement of the calvarium in systemic mastocytosis is a very rare entity. Medullar involvement of the calvarium leads to enlargement on bone causing narrowing of bony apertures and external compression of cranial nerves. Narrowing of both optic foramina leads to impaired vision by compressing optic nerves. Moreover, cavernous sinus involvement can initiate cranial nerve palsies and numbness due to external compression of cranial nerves within cavernous sinuses. These are very rare clinical manifestations of SM and can cause neurological signs and symptoms in SM patients 3,4. Lack of pathological confirma-
362
N. Bulakbasi
tion of meningeal reaction seen in adjacent dural surface prevents an explanation of its real nature, but thickening and contrast enhancement of adjacent meninges may be due to either mast cell infiltration or reactive enhancement of dura similar to that seen in postoperative patients 6. This is also responsible for the meningeal irritation findings seen in our patient. Meningeal involvement is not pathognomonic for SM and can be seen in several systemic disorders such as lymphoma, leukemia, Gaucher disease, and Langerhans cell histiocytosis 7,8. As previously described, MR imaging findings of SM are similar to diffuse bone marrow involvement seen in other myeloproliferative disorders such as leukemia, myelofibrosis, polycythemia vera and myelodysplastic syndromes and cannot be differentiated from these disorders on the basis of MR imaging findings alone 5-9. Replacement of fatty bone marrow with abnormally proliferated mast cells leads to diffuse low-signal intensity relative to normal bone marrow on T1 weighted images with mild heterogeneous contrast enhancement 5,9. Signal intensity on STIR images can vary from intermediate to high signal relative to normal bone marrow due to variation in the histologic distribution (uniform dispersion, small focal lesions or larger aggregates) of mast cells in the marrow of patients with SM 5. The pattern of marrow signal abnormality is not specific for any clinical category of mastocytosis 5. Narrowing of bony apertures and cranial nerve compression secondary to bone marrow infiltration is not a typical finding for hematological disorders but can occur due to cranial metastatic disease, non-Hodgkin lymphoma, leukemia, multiple myeloma, fibrous dysplasia, Paget disease, histiocytosis X, and anemia 8. In conclusion, SM should be taken into account in the differential diagnosis of systemic bone marrow involvement, cranial nerve palsies and clinical findings of meningeal irritation. MR imaging is the modality of choice in both detection and follow-up of SM and is also useful for its differential diagnosis and description of complications.
www. centauro. it
The Neuroradiology Journal 20: 359-363, 2007
References 1 Metcalfe DD, Akin C: Mastocytosis: molecular mechanisms and clinical disease heterogeneity. Leuk Res 25: 577-82, 2001. 2 Valent P, Horny H-P, Li CY et Al: Mastocytosis (mast cell disease). World Health Organization (WHO) classification of tumours. Pathology and genetics. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, (Eds). Tumours of haematopoietic and lymphoid tissues. Vol 1. World Health Organization. Lyon, France: IARC Press 2001: 291-302. 3 Valent P, Horny H-P, Escribano L et Al: Diagnostic criteria and classification of mastocytosis: a consensus proposal. Conference Report of Year 2000 Working Conference on Mastocytosis. Leuk Res 25: 603-25, 2001. 4 Valent P, Sperr WR, Schwartz LB et Al: Diagnosis and classification of mast cell proliferative disorders: delineation from immunologic diseases and non-mast cell hematopoietic neoplasms. J Allergy Clin Immunol 114: 3-11, 2004. 5 Avila NA, Ling A, Metvalfe DD, et Al: Mastocytosis: magnetic resonance imaging patterns of marrow disease. Skeletal Radiol 27: 119-126, 1998. 6 Ho LH, Lipper M: Mastocytosis of axial skeleton presenting as an epidural mass lesion: MR imaging appearance. Am J Radiol 167: 716-718, 1996.
7 Hermann G, Shapiro RS, Abdelwahab IH et Al: MR imaging in adults with Gaucher disease type Y: Evaluation of marrow involvement and disease activity. Skeletal Radiol 22: 247-251, 1993. 8 Harnsberger HR (Ed): The skull base. In: Handbook of Head and Neck Imaging. 2nd ed, Mosby, St Louis 1995: 399-425. 9 Roca M, Mota J, Giraldo P et Al: Systemic mastocytosis: MRI of bone marrow involvement. Eur. Radiol 9: 1094-1097, 1999.
Nail Bulakbasi, MD Radiology Department Gulhane Military Medical Academy Etlik Ankara 06018 Turkey Tel.: 903123044701 Fax: 903123260551 E-mail: [email protected]
363
The Neuroradiology Journal 20: 359-363, 2007
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis. A Case Report N. BULAKBASI, M. KOCAOGLU, I. KARADEMIR, B. USTUNSOZ Radiology Deparment, Gulhane Military Medical Academy; Etlik, Ankara, Turkey
Key words: systemic mastocytosis, central nervous system involvement, computed tomography, magnetic resonance imaging
SUMMARY – Central nervous system involvement in systemic mastocytosis (SM) is very rare. This case report describes the computed tomography and magnetic resonance (MR) imaging findings of central nervous system involvement in a patient with isolated bone marrow mastocystosis. Bone marrow infiltration in SM caused cranial nerve dysfunction and meningeal irritation secondary to narrowing of cranial apertures and meningeal involvement, respectively. MR imaging is the modality of choice in both detection and follow-up of SM and also useful for differential diagnosis and detection of complications.
Introduction
Case Report
Mastocytosis is a rare heterogeneous group of disorders characterized by abnormal proliferation and accumulation of mast cells in one (skin) or more organ systems (bone marrow, liver, spleen, gastrointestinal mucosa and lymph nodes) 1. According to the updated consensus classification of WHO, mastocytosis is classified into seven clinical categories of disease on the basis of pathologic findings, clinical presentation, and prognosis 2,3. These subgroups include (a) cutaneous mastocytosis (CM), (b) indolent systemic mastocytosis (SM), (c) SM with an associated clonal hematologic none mast cell lineage disease, (d) aggressive SM, (e) mast cell leukemia, (f ) mast cell sarcoma, and (g) extracutaneous mastocytoma. The WHO classification includes criteria for the differentiation of SM and CM both from each other and from the other myelomastocytic disorders 2,3. Isolated bone-marrow mastocytosis is a subgroup of indolent SM in which mediator-related symptoms are not recorded as frequently as in other subtypes of mastocytosis 4. This case report describes the magnetic resonance (MR) imaging findings of central nervous system involvement in a patient with isolated bone marrow mastocytosis.
A 42-year-old man with clinical and pathological diagnosis of isolated bone marrow mastocystosis was examined by computed tomography (CT) and MR imaging because of progressive blurred vision, numbness on different facial areas, mild meningeal irritation findings and back pain. CT images were obtained with a helical CT scanner (GE Hispeed CT/i, Milwaukee, USA) with 120 kV and 210 mAs, 25 cm FOV and contiguous 5 mm slices from neck to vertex covering the whole face and cranium. All MR measurements were performed on a 1.5 T whole-body MR system (The New Intera Nova; Philips Medical Systems, Best, the Netherlands) using a standard quadrature head and spine coils. For routine brain examination, axial T1-weighted (583/15 ms; 1 excitation) spinecho, T2-weighted (2295/90 ms; 2 excitations) spin-echo, and fast fluid-attenuated inversion recovery (FLAIR) (8000/100/2000 ms; 1 excitation) images were obtained using 5-mm section thickness with 1-mm intersection gap, 220 × 220 mm field of view, and 256 × 256 matrix size. Contrast enhanced T1-weighted spin-echo images were also obtained in the three orthogonal planes following intravenous administra359
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis
A
B
C
D
N. Bulakbasi
Figure 1 A 42-year-old man with isolated bone marrow mastocytosis. A,B) Axial CT images through skull base A) and lateral ventricular B) levels show prominent bone marrow enlargement and cortical thinning. C) Axial T1-weighted image at the level of skull base demonstrates low signal of infiltrated bone marrow. Lateral wall of left orbita is also involved together with the temporal and intracranial surfaces of sphenoid bone. Subperiostal soft tissues are seen in the orbita and around of the ala major. D) Axial T2-weighted images from the skull base show widespread high signal intensity due to mastocyte infiltration, which causes external compression to transverse sinuses (arrowheads). Fluid levels in both middle ear and mastoid cells (arrows) are also noted due to obliteration of both Eustachian tubes. E, F) Postcontrast T1-weighted axial (E) and coronal (F) images imply significant contrast enhancement of infiltrated bone marrow. Bone marrow enlargement causes encasement of optic foramens (small arrows) and cavernous sinuses (arrowheads). Note bilateral meningeal thickening and enhancement (large arrows). The lateral wall of the left orbita is also involved together with the temporal and intracranial surfaces of sphenoid bone. Subperiostal soft tissues are seen in the orbita and around the ala major. G, H) Sagittal T1-weighted (G) and STIR(H) images of the cervical spine show diffuse bone marrow involvement causing diffuse low signal on T1 and high signal on STIR images. Note the biopsy defect in the upper thoracic region (arrow).
360
www. centauro. it
The Neuroradiology Journal 20: 359-363, 2007
E
F
G
H
361
Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis
tion of gadodiamid at a dose of 0.2 mmol/kg. For spine MR study, sagittal and axial short tau inversion recovery (STIR, TR/TE/TI 2500/20/150 ms), pre- and post-contrast T1 (TR/TE 600/15 ms) weighted images were obtained using 3mm section thickness with 1 mm intersection gap, 275 × 100 mm field of view, and 256 × 256 matrix size. Widespread bone marrow involvement in skull base, both orbit and calvarium caused bony enlargement and cortical thinning on CT scans (figure 1 A,B). Infiltrated bone morrow showed heterogeneous low signal intensity on T1- (figure 1 C) and high signal on T2-weighted (figure 1 D) images with heterogeneous enhancement (figure 1 E,F). Widespread meningeal thickening and enhancement was also noted in the adjacent dural surface (figure 1 E). Bone marrow involvement of sphenoid bone caused encasement of both cavernous sinuses (figure 1 E-F). On spinal images extensive bone marrow involvement of vertebral bodies was detected without prominent enlargement or destruction (figure 1 G.H). Discussion Bone marrow infiltration of the axial skeleton is a well-known manifestation of SM that occurs in 79% of patients and is commonly asymptomatic, but it may cause pain, tenderness or pathological fractures, mostly in the spine 5,6. Bone marrow involvement of the calvarium in systemic mastocytosis is a very rare entity. Medullar involvement of the calvarium leads to enlargement on bone causing narrowing of bony apertures and external compression of cranial nerves. Narrowing of both optic foramina leads to impaired vision by compressing optic nerves. Moreover, cavernous sinus involvement can initiate cranial nerve palsies and numbness due to external compression of cranial nerves within cavernous sinuses. These are very rare clinical manifestations of SM and can cause neurological signs and symptoms in SM patients 3,4. Lack of pathological confirma-
362
N. Bulakbasi
tion of meningeal reaction seen in adjacent dural surface prevents an explanation of its real nature, but thickening and contrast enhancement of adjacent meninges may be due to either mast cell infiltration or reactive enhancement of dura similar to that seen in postoperative patients 6. This is also responsible for the meningeal irritation findings seen in our patient. Meningeal involvement is not pathognomonic for SM and can be seen in several systemic disorders such as lymphoma, leukemia, Gaucher disease, and Langerhans cell histiocytosis 7,8. As previously described, MR imaging findings of SM are similar to diffuse bone marrow involvement seen in other myeloproliferative disorders such as leukemia, myelofibrosis, polycythemia vera and myelodysplastic syndromes and cannot be differentiated from these disorders on the basis of MR imaging findings alone 5-9. Replacement of fatty bone marrow with abnormally proliferated mast cells leads to diffuse low-signal intensity relative to normal bone marrow on T1 weighted images with mild heterogeneous contrast enhancement 5,9. Signal intensity on STIR images can vary from intermediate to high signal relative to normal bone marrow due to variation in the histologic distribution (uniform dispersion, small focal lesions or larger aggregates) of mast cells in the marrow of patients with SM 5. The pattern of marrow signal abnormality is not specific for any clinical category of mastocytosis 5. Narrowing of bony apertures and cranial nerve compression secondary to bone marrow infiltration is not a typical finding for hematological disorders but can occur due to cranial metastatic disease, non-Hodgkin lymphoma, leukemia, multiple myeloma, fibrous dysplasia, Paget disease, histiocytosis X, and anemia 8. In conclusion, SM should be taken into account in the differential diagnosis of systemic bone marrow involvement, cranial nerve palsies and clinical findings of meningeal irritation. MR imaging is the modality of choice in both detection and follow-up of SM and is also useful for its differential diagnosis and description of complications.
www. centauro. it
The Neuroradiology Journal 20: 359-363, 2007
References 1 Metcalfe DD, Akin C: Mastocytosis: molecular mechanisms and clinical disease heterogeneity. Leuk Res 25: 577-82, 2001. 2 Valent P, Horny H-P, Li CY et Al: Mastocytosis (mast cell disease). World Health Organization (WHO) classification of tumours. Pathology and genetics. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, (Eds). Tumours of haematopoietic and lymphoid tissues. Vol 1. World Health Organization. Lyon, France: IARC Press 2001: 291-302. 3 Valent P, Horny H-P, Escribano L et Al: Diagnostic criteria and classification of mastocytosis: a consensus proposal. Conference Report of Year 2000 Working Conference on Mastocytosis. Leuk Res 25: 603-25, 2001. 4 Valent P, Sperr WR, Schwartz LB et Al: Diagnosis and classification of mast cell proliferative disorders: delineation from immunologic diseases and non-mast cell hematopoietic neoplasms. J Allergy Clin Immunol 114: 3-11, 2004. 5 Avila NA, Ling A, Metvalfe DD, et Al: Mastocytosis: magnetic resonance imaging patterns of marrow disease. Skeletal Radiol 27: 119-126, 1998. 6 Ho LH, Lipper M: Mastocytosis of axial skeleton presenting as an epidural mass lesion: MR imaging appearance. Am J Radiol 167: 716-718, 1996.
7 Hermann G, Shapiro RS, Abdelwahab IH et Al: MR imaging in adults with Gaucher disease type Y: Evaluation of marrow involvement and disease activity. Skeletal Radiol 22: 247-251, 1993. 8 Harnsberger HR (Ed): The skull base. In: Handbook of Head and Neck Imaging. 2nd ed, Mosby, St Louis 1995: 399-425. 9 Roca M, Mota J, Giraldo P et Al: Systemic mastocytosis: MRI of bone marrow involvement. Eur. Radiol 9: 1094-1097, 1999.
Nail Bulakbasi, MD Radiology Department Gulhane Military Medical Academy Etlik Ankara 06018 Turkey Tel.: 903123044701 Fax: 903123260551 E-mail: [email protected]
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