Rheumatology
Rheumatol Int DOI 10.1007/s00296-014-3170-4
INTERNATIONAL
ORIGINAL ARTICLE - CASES WITH A MESSAGE
Osseous sarcoidosis: a case series Halyna Kuzyshyn · David Feinstein · Sharon L. Kolasinski · Hala Eid
Received: 18 July 2014 / Accepted: 28 October 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Sarcoidosis is an inflammatory disorder characterized by noncaseating granulomas infiltrating affected organs. Any organ system can be involved, and more than 90 % of patients have a primary pulmonary manifestation. The incidence of radiographically evident bone involvement has been reported over a wide range: from 3 to 39 % depending on the population studied and imaging modalities used. Any bone may be affected in osseous sarcoidosis. Bilateral involvement of the phalanges of the hand and feet is most common. However, reports of long bone, skull, rib and vertebral involvement have appeared. To date, there are no specific tools for the assessment of skeletal disease activity in sarcoidosis. Plain radiograph picks lesions in the small bones of hands and feet greater than does in other bones. Bone scan is useful for defining the extent of the skeletal disease and bone marrow involvement. Magnetic resonance imaging usually demonstrates multifocal lesions within the vertebrae that are hypointense on T1-weighted images and hyperintense on T2-weighted images. In cases of multifocal bone lesions and an established diagnosis of sarcoidosis, a diagnosis of bone sarcoidosis should be considered in the differential diagnosis. Optimal treatment of osseous sarcoidosis remains controversial. We present five cases of multisystem sarcoidosis with skeletal involvement including long bones and vertebrae and a description of immunosuppressive therapies used in our patients. A literature review highlighting the diagnostic approach using radiographic imaging, as well as treatment strategies, is provided.
H. Kuzyshyn (*) · D. Feinstein · S. L. Kolasinski · H. Eid Division of Rheumatology, Cooper University Hospital, Camden, NJ 08103, USA e-mail: [email protected]
Keywords Sarcoidosis · Bone lesions · Granuloma · Cytokines · Radiographic imaging
Case reports Case 1 A 51-year-old Caucasian man with a 4-year history of asymptomatic (not requiring treatment) biopsy-proven pulmonary sarcoidosis, presented with weight loss, night sweats, microcytic anemia with a hemoglobin of 9.6 g/dL (14.0–18.0 g/dl), mild thrombocytopenia with a platelet count of at 124 × 103/μL (150–400 × 103/μL), moderate leucopenia with a white blood cell count of 2.1 × 103/μL (4.5–11.0 × 103/μL) and elevated angiotensin converting enzyme (ACE) level of 135 μg/ml (5.0–20.0 μg/ml). Computed tomography scan of the chest, abdomen and pelvis revealed mediastinal, supraclavicular and retroperitoneal lymphadenopathy, numerous subcentimeter nodules in the lungs, an enlarged spleen and an enlarged liver. Imaging also demonstrated lytic lesions in the vertebral bodies of T1, T2, T3, T8, T10, the right ileum and both ischial tuberosities. Biopsy of a left periaortic lymph node revealed chronic inflammation with noncaseating granulomas. Biopsy of bone marrow taken from the right posterior iliac crest also revealed a focus of noncaseating granulomatous inflammation with multinucleated giant cells consistent with a diagnosis of sarcoidosis. Treatment with high dose of prednisone was initiated, but the patient was lost to follow-up for next 3 years and did not continue therapy with steroids. Three years later, he presented with cachexia, arthralgia and back pain, severe pancytopenia, and advanced liver cirrhosis confirmed by liver biopsy.
13
Rheumatol Int
Fig. 1 A 34-year-old woman with 4-year history of biopsy-proven pulmonary sarcoidosis developed severe bilateral knee pain. Coronal T1-weighted (a) and T2-weighted (b) images reveal multiple foci within the bone marrow of the distal femur and proximal tibia right knee
Case 2 A 30-year-old Hispanic woman presented with an acute onset of symmetrical ankle pain and swelling and hilar lymphadenopathy. A diagnosis of sarcoidosis with pulmonary involvement was made. Hilar lymph node biopsy was performed, and pathologic examination demonstrated a noncaseating granuloma. She was treated with prednisone and her disease remained clinically quiescent until 2 years later when she developed pain and swelling in the knees, ankles and wrists, and positive anti-cyclic citrullinated peptide antibody. The patient was treated with methotrexate and etanercept for 1 year for rheumatoid arthritis. The pain and swelling in both ankles and wrists resolved, but she continued to have significant pain in both knees. The following year, magnetic resonance imaging (MRI) of the knees was performed, and approximately 30 2–5 mm foci of abnormal intensity (on T1 and T2) within the distal femur and proximal tibia were seen. The findings were suggestive of osseous sarcoidosis, given clinical history of biopsy-proven pulmonary sarcoidosis. Due to the worsening of symptoms along with the diffuse osseous abnormalities, etanercept was discontinued and infliximab was added to the methotrexate. The patient did not tolerate infliximab due to allergic reaction. Adalimumab was denied by insurance. Eighteen months after initial, MRI of both knees was repeated and showed unchanged multiple foci of abnormal bone marrow signal intensity within the distal femur and proximal tibia (Fig. 1). Decision was made to try golimumab. Over the subsequent year, her knee pain persisted despite ongoing use of methotrexate and golimumab and felt to be part of opiod dependency. Clinical course was also complicated by multiple admissions to intensive care unit for sepsis, which lead to stopping biological therapy. Knee MRI repeated 3 years
13
after initial showed much less well defined and more confluent bone marrow signaling in the distal femur and proximal tibia. Radiographically, it represented resolution of sarcoid lesions and replacement by bone marrow (Fig. 2). Case 3 A 63-year-old Caucasian man with an 8-year history of biopsy-proven pulmonary sarcoidosis was treated initially with prednisone and methotrexate for 6 months. As his pulmonary symptoms improved, his methotrexate was discontinued after 1 year and his steroid dose was reduced. Six years later, he developed lower back and left leg pain. Lumbar spine MRI showed multilevel degenerative disc disease as well as multiple areas of signal abnormalities involving the lumbar vertebral bodies and sacrum suspicious for metastatic cancer (Fig. 3a, b). A bone scan showed increased isotope uptake in the lumbar spine and sacrum, left femur, left humerus and coracoids, also consistent with skeletal metastases. He was evaluated by an oncologist who suggested an alternative diagnosis of osseous sarcoidosis. MRI of left leg revealed lesions in the left femur (Fig. 3c, d). Methotrexate and prednisone were restarted. Over next 6 months, methotrexate was titrated up to 15 mg by mouth weekly and prednisone was tapered and discontinued. The patient reported resolution of the low back and left leg pain. One year later, a repeat MRI showed an unchanged appearance of the multiple intramedullary lesions in the lumbar spine, sacrum, left femur, left humerus and coracoid. Case 4 A 53-year-old African-American woman presented with a 3-year history of vague, diffuse back pain. Lumbar spine
Rheumatol Int
Fig. 2 Coronal T1-weighted (a) and T2-weighted (b) images reveal less well defined and more confluent abnormal signal intensity within the bone marrow of the distal femur and proximal tibia right knee
radiographs showed abnormalities suggestive metastasis that prompted MRI. MRI of the chest and spine revealed multiple lung nodules, mediastinal lymphadenopathy and multiple lytic lesions throughout the entire thoracolumbar spine (Fig. 4). Mediastinal lymph node biopsy showed normal lymphocytes without any evidence of malignancy or lymphoproliferative disorder. Bone marrow biopsy and biopsy of the fourth lumbar vertebra were also normal. No evidence of malignancy, infection or granuloma was noted. Age appropriate cancer screening revealed no evidence of malignancy. On follow-up examination, papular skin lesions were identified on the scalp. Skin biopsy of the involved area revealed granulomatous dermatitis suggestive of sarcoidosis. A diagnosis of sarcoidosis with multisystem involvement was made based on multiple lung nodules, mediastinal lymphadenopathy, noncaseating granuloma on skin biopsy, lytic lesions in her spine and a negative malignancy workup. Prednisone and methotrexate were initiated with subsequent improvement in the patient’s back pain.
right foot numbness. There was no evidence of sarcoidosis involving other organs. PET scan and CT scan showed no evidence of lymphoma recurrence. However, repeated CT scan of the lumbosacral spine demonstrated stable multiple areas of ill-defined hypodensity within the vertebral bodies of L1, L2 and L4, as well as the sacrum and both iliac bones that were unremarkable on PET scan. Laboratory test for inflammatory arthritis resulted in positive RF, positive ANA, elevated CRP and elevated ACE level. Methotrexate and prednisone were initiated, and adalimumab was added few months later because of persistent synovitis. The patient had excellent response to treatment in terms of polyarthritis symptoms within next 3 months and was weaned off prednisone. Her osseous sarcoidosis has remained asymptomatic with no radiographic progression and no signs of systemic involvement.
Case 5
We report five cases of osseous sarcoidosis with lesions in the long bones and axial skeleton. Three patients had multifocal lesions involving vertebral bodies, one had long bone involvement alone, and one had both vertebral and long bone lytic lesions. Four patients had evidence of pulmonary involvement, which is usually present in patients with osseous sarcoidosis. These four patients were clinically symptomatic, which prompted MRI imaging to identify bony lesions. It indicates that MRI is sensitive imaging modality for osseous sarcoidosis. We believe that low index of suspicion for osseous sarcoidosis should be present in patient with history of sarcoidosis in the right clinical setting. In two cases, clinical remission with pain improvement was achieved on prednisone and methotrexate. TNF antagonists
A 53-year-old Caucasian woman with a history of Hodgkin’s lymphoma and osseous sarcoidosis developed symmetrical polyarthritis associated with morning stiffness. She was diagnosed with Hodgkin’s lymphoma with primarily epidural and bone involvement at age 40, underwent successful treatment with 6 cycles of ABVD (adriamycin, bleomycin, vinblastine, decarbazine) chemotherapy. At the same time, the patient was diagnosed with osseous sarcoidosis involving the vertebral bodies of L1, L2 and L4, both iliac bones and sacrum, based on PET scan and bone biopsy. She required internal fixation of the L3 to L5 vertebrae, but continued to have chronic lower back pain and
Discussion
13
Rheumatol Int
Fig. 3 A 63-year-old Caucasian man with 8-year history of biopsyproven stable pulmonary sarcoidosis developed lower back and left leg pain. Sagittal T1-weighted (a) and T2-weighted (b) images reveal
multiple intramedullary foci in lumbar spine and sacrum. Coronal T1-weighted (c) and T2-weighted (d) images of left femur show multiple intramedullary lesions
were used in one patient and lead to radiographic resolution of bone lesions.
well-defined granuloma formed by the accumulation of epithelial cells, multinucleated giant cells, lymphocytes, macrophages and fibroblasts. The center of the granuloma is composed of macrophage-derived cells and CD4+ T cells, whereas the periphery of the granuloma is composed of a large number of antigen-presenting interdigitating macrophages, CD4+ and CD8+ T cells [30, 31].
Granuloma of sarcoidosis in the bone The histological findings of sarcoidosis in the bone are precisely the same as they are in other tissues of the body [12]. The lesion of sarcoidosis is a focal
13
Rheumatol Int
Fig. 4 A 53-year-old African-American woman with 3-year history of vague diffuse back pain. Sagittal T1-weighted (a) and T2-weighted (b) lesions seen throughout the thoracic and lumbar vertebral bodies
Osseous sarcoidosis: Uncommon or underestimated?
Types of bone lesions and imaging techniques
The reported incidence for osseous sarcoidosis varies widely between 3 to 13 % [1] on conventional imaging by plain radiographs and 39 % [2] using the combination of bone scintigraphy and plain radiographs. However, the prevalence is unknown. In the era of frequent use of MRI, computed tomography (CT) and technetium bone scans osseous sarcoidosis lesions are found more often and may be revealed as incidental findings in a subject imaged for other indications. Uncommonly, sarcoidosis bone lesions resembling bone metastases may be the initial presentation of undiagnosed disease [5, 6]. As in other forms of sarcoidosis, a biopsy is required to establish the diagnosis of osseous lesions. It is not possible to distinguish granulomatous bone involvement from other causes by MRI or other imaging studies, making biopsy necessary for diagnosis [7–11].
A plain radiograph cannot reliably reflect early bone lesions, only the gross changes are clear. Conventional radiography usually reveals the location of sarcoid bone lesions in the small bones of the hands and feet. The bony lesions are usually lytic (also called bone cysts, but the term is the misnomer) as the result of osteolysis. The following radiographic features of 136 cases of osseous sarcoidosis involving hands and feet described by Yaghmai [12]: diffuse marrow infiltrate (identified better by bone scintigraphy), punched-out lesions, permeative lesions (reticular pattern), destructive lesions (dactylitis) and sclerotic lesions (rare, usually seen in the late stage of disease after longterm treatment). Diffuse marrow infiltration with absorption and disruption of bone trabeculae is more frequently, earlier and accurately identified by bone scan than plain radiograph. Punched-out lesions are small cortical defects surrounded by normal bone, usually seen in relatively unaggressive sarcoidosis, and persist indefinitely. Permeative lesions start with tunneling in the cortex of the shafts of small bones, followed by remodeling of the cortical and trabecular architecture to give a reticular pattern. This type of lesion is not as commonly seen as punched out. Destructive lesions include rapidly advancing bone involvement with multiple fractures, devitalized cortex, considerable soft tissue swelling, but no periosteal reaction such as new bone formation. Destructive lesions are rare and seen in
Rheumatol Int DOI 10.1007/s00296-014-3170-4
INTERNATIONAL
ORIGINAL ARTICLE - CASES WITH A MESSAGE
Osseous sarcoidosis: a case series Halyna Kuzyshyn · David Feinstein · Sharon L. Kolasinski · Hala Eid
Received: 18 July 2014 / Accepted: 28 October 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Sarcoidosis is an inflammatory disorder characterized by noncaseating granulomas infiltrating affected organs. Any organ system can be involved, and more than 90 % of patients have a primary pulmonary manifestation. The incidence of radiographically evident bone involvement has been reported over a wide range: from 3 to 39 % depending on the population studied and imaging modalities used. Any bone may be affected in osseous sarcoidosis. Bilateral involvement of the phalanges of the hand and feet is most common. However, reports of long bone, skull, rib and vertebral involvement have appeared. To date, there are no specific tools for the assessment of skeletal disease activity in sarcoidosis. Plain radiograph picks lesions in the small bones of hands and feet greater than does in other bones. Bone scan is useful for defining the extent of the skeletal disease and bone marrow involvement. Magnetic resonance imaging usually demonstrates multifocal lesions within the vertebrae that are hypointense on T1-weighted images and hyperintense on T2-weighted images. In cases of multifocal bone lesions and an established diagnosis of sarcoidosis, a diagnosis of bone sarcoidosis should be considered in the differential diagnosis. Optimal treatment of osseous sarcoidosis remains controversial. We present five cases of multisystem sarcoidosis with skeletal involvement including long bones and vertebrae and a description of immunosuppressive therapies used in our patients. A literature review highlighting the diagnostic approach using radiographic imaging, as well as treatment strategies, is provided.
H. Kuzyshyn (*) · D. Feinstein · S. L. Kolasinski · H. Eid Division of Rheumatology, Cooper University Hospital, Camden, NJ 08103, USA e-mail: [email protected]
Keywords Sarcoidosis · Bone lesions · Granuloma · Cytokines · Radiographic imaging
Case reports Case 1 A 51-year-old Caucasian man with a 4-year history of asymptomatic (not requiring treatment) biopsy-proven pulmonary sarcoidosis, presented with weight loss, night sweats, microcytic anemia with a hemoglobin of 9.6 g/dL (14.0–18.0 g/dl), mild thrombocytopenia with a platelet count of at 124 × 103/μL (150–400 × 103/μL), moderate leucopenia with a white blood cell count of 2.1 × 103/μL (4.5–11.0 × 103/μL) and elevated angiotensin converting enzyme (ACE) level of 135 μg/ml (5.0–20.0 μg/ml). Computed tomography scan of the chest, abdomen and pelvis revealed mediastinal, supraclavicular and retroperitoneal lymphadenopathy, numerous subcentimeter nodules in the lungs, an enlarged spleen and an enlarged liver. Imaging also demonstrated lytic lesions in the vertebral bodies of T1, T2, T3, T8, T10, the right ileum and both ischial tuberosities. Biopsy of a left periaortic lymph node revealed chronic inflammation with noncaseating granulomas. Biopsy of bone marrow taken from the right posterior iliac crest also revealed a focus of noncaseating granulomatous inflammation with multinucleated giant cells consistent with a diagnosis of sarcoidosis. Treatment with high dose of prednisone was initiated, but the patient was lost to follow-up for next 3 years and did not continue therapy with steroids. Three years later, he presented with cachexia, arthralgia and back pain, severe pancytopenia, and advanced liver cirrhosis confirmed by liver biopsy.
13
Rheumatol Int
Fig. 1 A 34-year-old woman with 4-year history of biopsy-proven pulmonary sarcoidosis developed severe bilateral knee pain. Coronal T1-weighted (a) and T2-weighted (b) images reveal multiple foci within the bone marrow of the distal femur and proximal tibia right knee
Case 2 A 30-year-old Hispanic woman presented with an acute onset of symmetrical ankle pain and swelling and hilar lymphadenopathy. A diagnosis of sarcoidosis with pulmonary involvement was made. Hilar lymph node biopsy was performed, and pathologic examination demonstrated a noncaseating granuloma. She was treated with prednisone and her disease remained clinically quiescent until 2 years later when she developed pain and swelling in the knees, ankles and wrists, and positive anti-cyclic citrullinated peptide antibody. The patient was treated with methotrexate and etanercept for 1 year for rheumatoid arthritis. The pain and swelling in both ankles and wrists resolved, but she continued to have significant pain in both knees. The following year, magnetic resonance imaging (MRI) of the knees was performed, and approximately 30 2–5 mm foci of abnormal intensity (on T1 and T2) within the distal femur and proximal tibia were seen. The findings were suggestive of osseous sarcoidosis, given clinical history of biopsy-proven pulmonary sarcoidosis. Due to the worsening of symptoms along with the diffuse osseous abnormalities, etanercept was discontinued and infliximab was added to the methotrexate. The patient did not tolerate infliximab due to allergic reaction. Adalimumab was denied by insurance. Eighteen months after initial, MRI of both knees was repeated and showed unchanged multiple foci of abnormal bone marrow signal intensity within the distal femur and proximal tibia (Fig. 1). Decision was made to try golimumab. Over the subsequent year, her knee pain persisted despite ongoing use of methotrexate and golimumab and felt to be part of opiod dependency. Clinical course was also complicated by multiple admissions to intensive care unit for sepsis, which lead to stopping biological therapy. Knee MRI repeated 3 years
13
after initial showed much less well defined and more confluent bone marrow signaling in the distal femur and proximal tibia. Radiographically, it represented resolution of sarcoid lesions and replacement by bone marrow (Fig. 2). Case 3 A 63-year-old Caucasian man with an 8-year history of biopsy-proven pulmonary sarcoidosis was treated initially with prednisone and methotrexate for 6 months. As his pulmonary symptoms improved, his methotrexate was discontinued after 1 year and his steroid dose was reduced. Six years later, he developed lower back and left leg pain. Lumbar spine MRI showed multilevel degenerative disc disease as well as multiple areas of signal abnormalities involving the lumbar vertebral bodies and sacrum suspicious for metastatic cancer (Fig. 3a, b). A bone scan showed increased isotope uptake in the lumbar spine and sacrum, left femur, left humerus and coracoids, also consistent with skeletal metastases. He was evaluated by an oncologist who suggested an alternative diagnosis of osseous sarcoidosis. MRI of left leg revealed lesions in the left femur (Fig. 3c, d). Methotrexate and prednisone were restarted. Over next 6 months, methotrexate was titrated up to 15 mg by mouth weekly and prednisone was tapered and discontinued. The patient reported resolution of the low back and left leg pain. One year later, a repeat MRI showed an unchanged appearance of the multiple intramedullary lesions in the lumbar spine, sacrum, left femur, left humerus and coracoid. Case 4 A 53-year-old African-American woman presented with a 3-year history of vague, diffuse back pain. Lumbar spine
Rheumatol Int
Fig. 2 Coronal T1-weighted (a) and T2-weighted (b) images reveal less well defined and more confluent abnormal signal intensity within the bone marrow of the distal femur and proximal tibia right knee
radiographs showed abnormalities suggestive metastasis that prompted MRI. MRI of the chest and spine revealed multiple lung nodules, mediastinal lymphadenopathy and multiple lytic lesions throughout the entire thoracolumbar spine (Fig. 4). Mediastinal lymph node biopsy showed normal lymphocytes without any evidence of malignancy or lymphoproliferative disorder. Bone marrow biopsy and biopsy of the fourth lumbar vertebra were also normal. No evidence of malignancy, infection or granuloma was noted. Age appropriate cancer screening revealed no evidence of malignancy. On follow-up examination, papular skin lesions were identified on the scalp. Skin biopsy of the involved area revealed granulomatous dermatitis suggestive of sarcoidosis. A diagnosis of sarcoidosis with multisystem involvement was made based on multiple lung nodules, mediastinal lymphadenopathy, noncaseating granuloma on skin biopsy, lytic lesions in her spine and a negative malignancy workup. Prednisone and methotrexate were initiated with subsequent improvement in the patient’s back pain.
right foot numbness. There was no evidence of sarcoidosis involving other organs. PET scan and CT scan showed no evidence of lymphoma recurrence. However, repeated CT scan of the lumbosacral spine demonstrated stable multiple areas of ill-defined hypodensity within the vertebral bodies of L1, L2 and L4, as well as the sacrum and both iliac bones that were unremarkable on PET scan. Laboratory test for inflammatory arthritis resulted in positive RF, positive ANA, elevated CRP and elevated ACE level. Methotrexate and prednisone were initiated, and adalimumab was added few months later because of persistent synovitis. The patient had excellent response to treatment in terms of polyarthritis symptoms within next 3 months and was weaned off prednisone. Her osseous sarcoidosis has remained asymptomatic with no radiographic progression and no signs of systemic involvement.
Case 5
We report five cases of osseous sarcoidosis with lesions in the long bones and axial skeleton. Three patients had multifocal lesions involving vertebral bodies, one had long bone involvement alone, and one had both vertebral and long bone lytic lesions. Four patients had evidence of pulmonary involvement, which is usually present in patients with osseous sarcoidosis. These four patients were clinically symptomatic, which prompted MRI imaging to identify bony lesions. It indicates that MRI is sensitive imaging modality for osseous sarcoidosis. We believe that low index of suspicion for osseous sarcoidosis should be present in patient with history of sarcoidosis in the right clinical setting. In two cases, clinical remission with pain improvement was achieved on prednisone and methotrexate. TNF antagonists
A 53-year-old Caucasian woman with a history of Hodgkin’s lymphoma and osseous sarcoidosis developed symmetrical polyarthritis associated with morning stiffness. She was diagnosed with Hodgkin’s lymphoma with primarily epidural and bone involvement at age 40, underwent successful treatment with 6 cycles of ABVD (adriamycin, bleomycin, vinblastine, decarbazine) chemotherapy. At the same time, the patient was diagnosed with osseous sarcoidosis involving the vertebral bodies of L1, L2 and L4, both iliac bones and sacrum, based on PET scan and bone biopsy. She required internal fixation of the L3 to L5 vertebrae, but continued to have chronic lower back pain and
Discussion
13
Rheumatol Int
Fig. 3 A 63-year-old Caucasian man with 8-year history of biopsyproven stable pulmonary sarcoidosis developed lower back and left leg pain. Sagittal T1-weighted (a) and T2-weighted (b) images reveal
multiple intramedullary foci in lumbar spine and sacrum. Coronal T1-weighted (c) and T2-weighted (d) images of left femur show multiple intramedullary lesions
were used in one patient and lead to radiographic resolution of bone lesions.
well-defined granuloma formed by the accumulation of epithelial cells, multinucleated giant cells, lymphocytes, macrophages and fibroblasts. The center of the granuloma is composed of macrophage-derived cells and CD4+ T cells, whereas the periphery of the granuloma is composed of a large number of antigen-presenting interdigitating macrophages, CD4+ and CD8+ T cells [30, 31].
Granuloma of sarcoidosis in the bone The histological findings of sarcoidosis in the bone are precisely the same as they are in other tissues of the body [12]. The lesion of sarcoidosis is a focal
13
Rheumatol Int
Fig. 4 A 53-year-old African-American woman with 3-year history of vague diffuse back pain. Sagittal T1-weighted (a) and T2-weighted (b) lesions seen throughout the thoracic and lumbar vertebral bodies
Osseous sarcoidosis: Uncommon or underestimated?
Types of bone lesions and imaging techniques
The reported incidence for osseous sarcoidosis varies widely between 3 to 13 % [1] on conventional imaging by plain radiographs and 39 % [2] using the combination of bone scintigraphy and plain radiographs. However, the prevalence is unknown. In the era of frequent use of MRI, computed tomography (CT) and technetium bone scans osseous sarcoidosis lesions are found more often and may be revealed as incidental findings in a subject imaged for other indications. Uncommonly, sarcoidosis bone lesions resembling bone metastases may be the initial presentation of undiagnosed disease [5, 6]. As in other forms of sarcoidosis, a biopsy is required to establish the diagnosis of osseous lesions. It is not possible to distinguish granulomatous bone involvement from other causes by MRI or other imaging studies, making biopsy necessary for diagnosis [7–11].
A plain radiograph cannot reliably reflect early bone lesions, only the gross changes are clear. Conventional radiography usually reveals the location of sarcoid bone lesions in the small bones of the hands and feet. The bony lesions are usually lytic (also called bone cysts, but the term is the misnomer) as the result of osteolysis. The following radiographic features of 136 cases of osseous sarcoidosis involving hands and feet described by Yaghmai [12]: diffuse marrow infiltrate (identified better by bone scintigraphy), punched-out lesions, permeative lesions (reticular pattern), destructive lesions (dactylitis) and sclerotic lesions (rare, usually seen in the late stage of disease after longterm treatment). Diffuse marrow infiltration with absorption and disruption of bone trabeculae is more frequently, earlier and accurately identified by bone scan than plain radiograph. Punched-out lesions are small cortical defects surrounded by normal bone, usually seen in relatively unaggressive sarcoidosis, and persist indefinitely. Permeative lesions start with tunneling in the cortex of the shafts of small bones, followed by remodeling of the cortical and trabecular architecture to give a reticular pattern. This type of lesion is not as commonly seen as punched out. Destructive lesions include rapidly advancing bone involvement with multiple fractures, devitalized cortex, considerable soft tissue swelling, but no periosteal reaction such as new bone formation. Destructive lesions are rare and seen in
