Ban Sharif | Imperial College London (original) (raw)

Papers by Ban Sharif

Skeletal Radiology, 2022

Rheumatoid arthritis is a multisystem, autoimmune, inflammatory disorder with numerous musculoske... more Rheumatoid arthritis is a multisystem, autoimmune, inflammatory disorder with numerous musculoskeletal manifestations. Involvement of the cervical spine is common and may result in severe complications due to synovitis, erosions, pannus formation, spinal instability and ankylosis. The purpose of this article is to review the current role of imaging in the rheumatoid spine, with emphasis on radiographs and MRI.

Poster: "ECR 2013 / C-0016 / An audit of chest X-ray requests in acute medical settings at a... more Poster: "ECR 2013 / C-0016 / An audit of chest X-ray requests in acute medical settings at a London teaching hospital – are guidelines being met?" by: "B. Sharif, A. Ratnarajah, K. O'Kane, S. McWilliams; London/UK"

Poster: "ESSR 2018 / P-0066 / A step-by-step imaging tour of congenital abnormalities of the... more Poster: "ESSR 2018 / P-0066 / A step-by-step imaging tour of congenital abnormalities of the foot" by: "B. Sharif, M. Khoo; Stanmore/UK"

Poster: "ESSR 2018 / P-0065 / A pictorial review of synovial chondromatosis" by: "... more Poster: "ESSR 2018 / P-0065 / A pictorial review of synovial chondromatosis" by: "B. Sharif, M. Khoo; Stanmore/UK"

Ollier disease and Maffucci syndrome are the commonest enchondromatosis subtypes, arising from no... more Ollier disease and Maffucci syndrome are the commonest enchondromatosis subtypes, arising from non-hereditary mutations in the IDH1 and IDH2 genes, presenting in childhood and being characterised by multiple enchondromas. Maffucci syndrome also includes multiple soft tissue haemangiomas. Aside from developing bony masses, osseous deformity and pathological fracture, ~ 40% of these patients develop secondary central chondrosarcoma, and there is increased risk of non-skeletal malignancies such as gliomas and mesenchymal ovarian tumours. In this review, we outline the molecular genetics, pathology and multimodality imaging features of solitary enchondroma, Ollier disease and Maffucci syndrome, along with their associated skeletal complications, in particular secondary chondrosarcoma. Given the lifelong risk of malignancy, imaging follow-up will also be explored. Metachondromatosis, a rare enchondromatosis subtype characterised by enchondromas and exostoses, will also be briefly outlined.

Skeletal Radiology

To identify magnetic resonance imaging (MRI) features which aid differentiation of low-grade chon... more To identify magnetic resonance imaging (MRI) features which aid differentiation of low-grade chondral tumours (LGCT-enchondroma and grade 1 chondrosarcoma) from high-grade chondral tumours (HGCT) in patients with enchondromatosis. Approval from our local Research and Innovation Centre of The Institute of Orthopaedics was gained. Patients with enchondromatosis who had biopsy and/or resection of chondral lesions over a 13-year period were identified. The pre-biopsy MRI study was assessed by two experienced musculoskeletal radiologists for tumour origin (intramedullary or surface), cortical expansion, cortical destruction, bone marrow oedema, periosteal reaction, soft tissue mass and soft tissue oedema. MRI features were compared with the final histopathological diagnosis. The study group comprised 25 males and 16 females, with a mean age of 34.9 years (range 6–81 years). Fifty-nine lesions were assessed (12 patients had > 1 tumour treated), including 43 LGCT and 16 HGCT. Significant MRI features suggesting malignant transformation to HGCT for both observers included bone oedema (p = < 0.001 and 0.002), periosteal reaction (p = 0.01) and soft tissue oedema (p = 0.001 and 0.05). Cortical destruction and soft tissue mass were predictors of HGCT in major long bones, but no significant differentiating features were identified in the hands and feet. The presence of bone oedema, periosteal reaction and soft tissue oedema on MRI may indicate a high-grade malignant transformation of chondral tumours in patients with enchondromatosis.

European Journal of Radiology

European Radiology

Objective To determine the prevalence of pulmonary metastases on re-staging chest CT at the time ... more Objective To determine the prevalence of pulmonary metastases on re-staging chest CT at the time of first local recurrence (LR) of trunk or extremity soft tissue sarcoma (STS). Materials and methods Retrospective review of all patients diagnosed with recurrent STS between May 2007 and April 2018. Data collected included patient age and sex, site of primary STS, time to LR, recurrence site, initial tumour grade, recurrent tumour grade, findings of initial staging chest CT, and prevalence of pulmonary metastases on re-staging chest CT. Results The study included 109 patients (males = 68, females = 41; mean age 56 years, range 9–92 years). The commonest tumour sub-types were myxofibrosarcoma (27.5%), undifferentiated pleomorphic/spindle cell sarcoma (20.2%), synovial sarcoma (10.1%), and malignant peripheral nerve sheath tumour (10.1%). Initial staging chest CT demonstrated pulmonary metastases in 1 of 77 (1.3%) patients for whom CT was available for review. The mean time to LR was 30.8 months (range 3–224 months). Pulmonary metastases were diagnosed on re-staging chest CT in 26 of 109 cases (23.9%), being commonest with grade 3 STS (36.1%). Pleomorphic sarcoma (85.7%) and undifferentiated spindle cell sarcoma (33.3%) were the 2 commonest tumour sub-types associated with pulmonary metastases at first LR. Conclusion Re-staging chest CT at the time of first LR of STS identified a prevalence of 23.9% pulmonary metastases, which supports the need for chest CT at the time of LR in line with the UK guidelines for the management of bone and soft tissue sarcoma. Key Points • Pulmonary metastases were diagnosed in 1.3% of soft tissue sarcomas at presentation. • Pulmonary metastases were identified in ~ 24% of patients at first local recurrence of soft tissue sarcoma, most commonly with pleomorphic sarcoma and Trojani grade tumours. • No patient with a low-grade recurrence had pulmonary metastases.

Skeletal Radiology

Introduction Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chon... more Introduction Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chondrosarcoma. The aim of this study was to determine the incidence of skip metastases on whole bone MRI in all primary high-grade sarcomas of the major long bones. Materials and method Retrospective review of patients from April 2007 to April 2019 with high-grade primary bone sarcomas of the humerus, radius, ulna, femur, tibia or fibula who had whole bone MRI at initial staging. Data collected included age, sex, tumour type, presence and location of skip metastases based on whole bone MRI and presence of distant metastases (the skeleton and lung). Results The study included 216 males and 171 females with mean age 30.6 years (range 4–92 years). Tumour types were as follows: High-grade osteosarcoma n = 202, Ewing sarcoma n = 68, high-grade chondrosarcoma n = 44, dedifferentiated chondrosarcoma n = 37, high-grade spindle cell sarcoma n = 29 and angiosarcoma n = 7. Skip lesions were identified in 63 (16.3%). However, after taking into account the presence of distant skeletal ( n = 11) and pulmonary ( n = 33) metastases, the overall incidence of skip metastases was 6.5%, occurring in 15 (7.5%) high-grade osteosarcomas, 3 (4.5%) Ewing sarcoma, 1 (2.8%) high-grade chondrosarcoma, 4 (10.8%) dedifferentiated chondrosarcomas, and 2 (6.9%) high-grade spindle cell sarcomas. A false positive MRI diagnosis of skip metastasis was made in 4 cases, 3 enchondromata and one focal nodular marrow hyperplasia. Conclusion The current study has documented the incidence of skip metastases in common types of high-grade primary bone sarcoma. The possibility of false positive skip metastases has also been highlighted.

Skeletal Radiology

The meniscal roots and supporting structures anchor the menisci to the tibial plateau and resist ... more The meniscal roots and supporting structures anchor the menisci to the tibial plateau and resist hoop stress, thereby preventing radial displacement of the menisci and secondary degenerative tibiofemoral compartment changes that may occur if this is compromised. The anatomy of the four meniscal roots and their supporting structures on magnetic resonance imaging (MRI) will be outlined in this review article, as well as the imaging appearances of meniscal root–related pathology, namely meniscal root degeneration and tears, meniscal extrusion and tibial plateau cystic lesions.

Ultrasound

Objectives To assess the inter-observer agreement amongst five observers of differing levels of e... more Objectives To assess the inter-observer agreement amongst five observers of differing levels of expertise in applying the British Thyroid Association (2014) guidelines for ultrasound scoring of thyroid nodules (BTA-U score) in the management of thyroid cancer, and to assess the U-score diagnostic performance in predicting malignancy. Method A total of 73 consecutive patients were included over a two-year period (July 2012 to July 2014), after referral to a tertiary head and neck oncology centre for ultrasound plus fine needle aspiration and cytology. Our five observers retrospectively and independently reviewed static ultrasound images on PACS and scored the thyroid nodules according to BTA-U classification. The observers were blinded to each other’s scoring, cytology and histology results. Either the Kappa-statistic or intra-class correlation was used to assess the level of inter-observer agreement, plus agreement between the radiological and cytological diagnoses. The diagnostic p...

Skeletal Radiology

The distal tibiofibular joint is a fibrous joint that plays a crucial role in the stability of th... more The distal tibiofibular joint is a fibrous joint that plays a crucial role in the stability of the ankle joint. It is stabilized by three main ligaments: the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the interosseous tibiofibular ligament, which are well delineated on magnetic resonance imaging. Pathology of the distal tibiofibular joint is mostly related to trauma and the longer-term complications of trauma, such as soft tissue impingement, heterotopic ossification, and synostosis. This review article outlines the MRI anatomy and pathology of this joint.

Skeletal Radiology

Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majo... more Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majority of cases being conventional intra-medullary high-grade tumours affecting the appendicular skeleton. Treatment is typically with a combination of neo-adjuvant chemotherapy, tumour resection with limb reconstruction and post-operative chemotherapy. The current article reviews the role of magnetic resonance imaging (MRI) in the pre-operative assessment of high-grade central conventional osteosarcoma.

Skeletal Radiology

The initial MRI demonstrates a subcutaneous mass overlying the posterior facet of the right great... more The initial MRI demonstrates a subcutaneous mass overlying the posterior facet of the right greater trochanter, in broad communication with the iliotibial band. It is of isointense T1-weighted signal compared to skeletal muscle (Fig. 1a), hyperintense signal on STIR (Fig. 1b), and demonstrates peripheral enhancement post-contrast with a central stellate, linear region of non-enhancement (Fig. 2). Ultrasound demonstrates an avascular hypoechoic mass (Fig. 3). A photomicrograph (4× H&E) obtained after needle biopsy shows fibrous tissue with ischemic-type necrosis, granulation tissue, and degenerative cytological atypia (Fig. 4). A follow-up MRI study performed 21 months later demonstrated complete resolution of the mass with minor residual subcutaneous scarring (Fig. 5). Ischemic fasciitis, also known as atypical decubital fibroplasia, was first described by Montgomery et al. in 1992 [1]. It is a rare pseudo-sarcomatous fibroblastic proliferation, occurring at bony prominences or pressure points in elderly bed-ridden patients, with a female preponderance and peak age of incidence in the 8th–9th decades. It belongs to a group of other pseudo-sarcomatous lesions, including nodular fasciitis, proliferative fasciitis, and proliferative myositis [2]. Patients typically present with a 1 to 8 cm soft tissue mass of short duration (< 6 months), commonly involving soft tissue at the shoulders, ribs, sacrococcygeal region, and greater trochanters [3, 4]. Lesions are usually in the subcutis, although may involve the dermis leading to epidermal ulceration, striated muscle, and adjacent periosteum [4]. The etiology is unknown, although trauma is a precipitant. The pathogenesis is related to intermittent ischemia, leading to tissue necrosis and breakdown followed by a regenerative and reparative process [5, 6]. MRI typically demonstrates a poorly circumscribed subcutaneous soft tissue mass at a pressure point with peri-lesional soft tissue edema, which is isointense to skeletal muscle on T1-weighted sequences and hyperintense on T2-weighted sequences. There may be associated breach of the fascia. Following gadolinium administration, there is intense peripheral enhancement with a non-enhancing central component, reflecting necrosis. A necrotic abscess or soft tissue sarcoma can have a similar appearance [2, 4, 7]. Macroscopically, lesions appear ill-defined, multinodular, and tan in color [4]. Microscopically, the hallmark of ischemic fasciitis is zonal variations with central fibrinoid necrosis surrounded by proliferative fibroblasts and prominent vessels [3, 5, 8]. Kaneko et al. described a sonographic biphasic zonal pattern in ischemic fasciitis (avascular hypoechoic central zone and hypervascular hyperechoic external zone), which reflects this distinctive histological zonal appearance [8]. Ultrasound can also guide needle biopsy, which was performed in this case and confirmed the presence of ischemic fasciitis. In general, local excision is the treatment of choice, since if left untreated the lesionmay persist and is often painful. In this case, the mass spontaneously resolved. Kaneko et al. [8] and Lehmer et al. [9] also described spontaneous resolution in 6 months-2 years following behavioral modification. Following resection, local recurrence is rare and there are no reported cases of malignant transformation [3, 4]. Ischemic fasciitis is rare and can simulate soft tissue sarcoma clinically, radiologically, and histologically. As elderly, immobilized patients with poor operative and anesthetic risks are affected, awareness of this rare condition is essential to prevent unnecessary over-treatment. The case presentation can be found at https://doi.org/10.1007/s00256018-3030-5

Skeletal Radiology

Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily ari... more Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily arise from the metaphyses of long and flat bones. Diaphyseal aclasis is an autosomal dominant condition resulting from EXT1 or EXT2 gene mutations and is characterized by multifocal osteochondromas. These can result in a wide spectrum of complications, such as skeletal deformity, neurological and vascular complications, adventitial bursa formation, fracture, and rarely malignant transformation to peripheral chondrosarcoma. In this review, we outline in detail the multimodality imaging features of DA and its associated complications.

Skeletal Radiology, 2022

Rheumatoid arthritis is a multisystem, autoimmune, inflammatory disorder with numerous musculoske... more Rheumatoid arthritis is a multisystem, autoimmune, inflammatory disorder with numerous musculoskeletal manifestations. Involvement of the cervical spine is common and may result in severe complications due to synovitis, erosions, pannus formation, spinal instability and ankylosis. The purpose of this article is to review the current role of imaging in the rheumatoid spine, with emphasis on radiographs and MRI.

Poster: "ECR 2013 / C-0016 / An audit of chest X-ray requests in acute medical settings at a... more Poster: "ECR 2013 / C-0016 / An audit of chest X-ray requests in acute medical settings at a London teaching hospital – are guidelines being met?" by: "B. Sharif, A. Ratnarajah, K. O'Kane, S. McWilliams; London/UK"

Poster: "ESSR 2018 / P-0066 / A step-by-step imaging tour of congenital abnormalities of the... more Poster: "ESSR 2018 / P-0066 / A step-by-step imaging tour of congenital abnormalities of the foot" by: "B. Sharif, M. Khoo; Stanmore/UK"

Poster: "ESSR 2018 / P-0065 / A pictorial review of synovial chondromatosis" by: "... more Poster: "ESSR 2018 / P-0065 / A pictorial review of synovial chondromatosis" by: "B. Sharif, M. Khoo; Stanmore/UK"

Ollier disease and Maffucci syndrome are the commonest enchondromatosis subtypes, arising from no... more Ollier disease and Maffucci syndrome are the commonest enchondromatosis subtypes, arising from non-hereditary mutations in the IDH1 and IDH2 genes, presenting in childhood and being characterised by multiple enchondromas. Maffucci syndrome also includes multiple soft tissue haemangiomas. Aside from developing bony masses, osseous deformity and pathological fracture, ~ 40% of these patients develop secondary central chondrosarcoma, and there is increased risk of non-skeletal malignancies such as gliomas and mesenchymal ovarian tumours. In this review, we outline the molecular genetics, pathology and multimodality imaging features of solitary enchondroma, Ollier disease and Maffucci syndrome, along with their associated skeletal complications, in particular secondary chondrosarcoma. Given the lifelong risk of malignancy, imaging follow-up will also be explored. Metachondromatosis, a rare enchondromatosis subtype characterised by enchondromas and exostoses, will also be briefly outlined.

Skeletal Radiology

To identify magnetic resonance imaging (MRI) features which aid differentiation of low-grade chon... more To identify magnetic resonance imaging (MRI) features which aid differentiation of low-grade chondral tumours (LGCT-enchondroma and grade 1 chondrosarcoma) from high-grade chondral tumours (HGCT) in patients with enchondromatosis. Approval from our local Research and Innovation Centre of The Institute of Orthopaedics was gained. Patients with enchondromatosis who had biopsy and/or resection of chondral lesions over a 13-year period were identified. The pre-biopsy MRI study was assessed by two experienced musculoskeletal radiologists for tumour origin (intramedullary or surface), cortical expansion, cortical destruction, bone marrow oedema, periosteal reaction, soft tissue mass and soft tissue oedema. MRI features were compared with the final histopathological diagnosis. The study group comprised 25 males and 16 females, with a mean age of 34.9 years (range 6–81 years). Fifty-nine lesions were assessed (12 patients had > 1 tumour treated), including 43 LGCT and 16 HGCT. Significant MRI features suggesting malignant transformation to HGCT for both observers included bone oedema (p = < 0.001 and 0.002), periosteal reaction (p = 0.01) and soft tissue oedema (p = 0.001 and 0.05). Cortical destruction and soft tissue mass were predictors of HGCT in major long bones, but no significant differentiating features were identified in the hands and feet. The presence of bone oedema, periosteal reaction and soft tissue oedema on MRI may indicate a high-grade malignant transformation of chondral tumours in patients with enchondromatosis.

European Journal of Radiology

European Radiology

Objective To determine the prevalence of pulmonary metastases on re-staging chest CT at the time ... more Objective To determine the prevalence of pulmonary metastases on re-staging chest CT at the time of first local recurrence (LR) of trunk or extremity soft tissue sarcoma (STS). Materials and methods Retrospective review of all patients diagnosed with recurrent STS between May 2007 and April 2018. Data collected included patient age and sex, site of primary STS, time to LR, recurrence site, initial tumour grade, recurrent tumour grade, findings of initial staging chest CT, and prevalence of pulmonary metastases on re-staging chest CT. Results The study included 109 patients (males = 68, females = 41; mean age 56 years, range 9–92 years). The commonest tumour sub-types were myxofibrosarcoma (27.5%), undifferentiated pleomorphic/spindle cell sarcoma (20.2%), synovial sarcoma (10.1%), and malignant peripheral nerve sheath tumour (10.1%). Initial staging chest CT demonstrated pulmonary metastases in 1 of 77 (1.3%) patients for whom CT was available for review. The mean time to LR was 30.8 months (range 3–224 months). Pulmonary metastases were diagnosed on re-staging chest CT in 26 of 109 cases (23.9%), being commonest with grade 3 STS (36.1%). Pleomorphic sarcoma (85.7%) and undifferentiated spindle cell sarcoma (33.3%) were the 2 commonest tumour sub-types associated with pulmonary metastases at first LR. Conclusion Re-staging chest CT at the time of first LR of STS identified a prevalence of 23.9% pulmonary metastases, which supports the need for chest CT at the time of LR in line with the UK guidelines for the management of bone and soft tissue sarcoma. Key Points • Pulmonary metastases were diagnosed in 1.3% of soft tissue sarcomas at presentation. • Pulmonary metastases were identified in ~ 24% of patients at first local recurrence of soft tissue sarcoma, most commonly with pleomorphic sarcoma and Trojani grade tumours. • No patient with a low-grade recurrence had pulmonary metastases.

Skeletal Radiology

Introduction Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chon... more Introduction Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chondrosarcoma. The aim of this study was to determine the incidence of skip metastases on whole bone MRI in all primary high-grade sarcomas of the major long bones. Materials and method Retrospective review of patients from April 2007 to April 2019 with high-grade primary bone sarcomas of the humerus, radius, ulna, femur, tibia or fibula who had whole bone MRI at initial staging. Data collected included age, sex, tumour type, presence and location of skip metastases based on whole bone MRI and presence of distant metastases (the skeleton and lung). Results The study included 216 males and 171 females with mean age 30.6 years (range 4–92 years). Tumour types were as follows: High-grade osteosarcoma n = 202, Ewing sarcoma n = 68, high-grade chondrosarcoma n = 44, dedifferentiated chondrosarcoma n = 37, high-grade spindle cell sarcoma n = 29 and angiosarcoma n = 7. Skip lesions were identified in 63 (16.3%). However, after taking into account the presence of distant skeletal ( n = 11) and pulmonary ( n = 33) metastases, the overall incidence of skip metastases was 6.5%, occurring in 15 (7.5%) high-grade osteosarcomas, 3 (4.5%) Ewing sarcoma, 1 (2.8%) high-grade chondrosarcoma, 4 (10.8%) dedifferentiated chondrosarcomas, and 2 (6.9%) high-grade spindle cell sarcomas. A false positive MRI diagnosis of skip metastasis was made in 4 cases, 3 enchondromata and one focal nodular marrow hyperplasia. Conclusion The current study has documented the incidence of skip metastases in common types of high-grade primary bone sarcoma. The possibility of false positive skip metastases has also been highlighted.

Skeletal Radiology

The meniscal roots and supporting structures anchor the menisci to the tibial plateau and resist ... more The meniscal roots and supporting structures anchor the menisci to the tibial plateau and resist hoop stress, thereby preventing radial displacement of the menisci and secondary degenerative tibiofemoral compartment changes that may occur if this is compromised. The anatomy of the four meniscal roots and their supporting structures on magnetic resonance imaging (MRI) will be outlined in this review article, as well as the imaging appearances of meniscal root–related pathology, namely meniscal root degeneration and tears, meniscal extrusion and tibial plateau cystic lesions.

Ultrasound

Objectives To assess the inter-observer agreement amongst five observers of differing levels of e... more Objectives To assess the inter-observer agreement amongst five observers of differing levels of expertise in applying the British Thyroid Association (2014) guidelines for ultrasound scoring of thyroid nodules (BTA-U score) in the management of thyroid cancer, and to assess the U-score diagnostic performance in predicting malignancy. Method A total of 73 consecutive patients were included over a two-year period (July 2012 to July 2014), after referral to a tertiary head and neck oncology centre for ultrasound plus fine needle aspiration and cytology. Our five observers retrospectively and independently reviewed static ultrasound images on PACS and scored the thyroid nodules according to BTA-U classification. The observers were blinded to each other’s scoring, cytology and histology results. Either the Kappa-statistic or intra-class correlation was used to assess the level of inter-observer agreement, plus agreement between the radiological and cytological diagnoses. The diagnostic p...

Skeletal Radiology

The distal tibiofibular joint is a fibrous joint that plays a crucial role in the stability of th... more The distal tibiofibular joint is a fibrous joint that plays a crucial role in the stability of the ankle joint. It is stabilized by three main ligaments: the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the interosseous tibiofibular ligament, which are well delineated on magnetic resonance imaging. Pathology of the distal tibiofibular joint is mostly related to trauma and the longer-term complications of trauma, such as soft tissue impingement, heterotopic ossification, and synostosis. This review article outlines the MRI anatomy and pathology of this joint.

Skeletal Radiology

Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majo... more Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majority of cases being conventional intra-medullary high-grade tumours affecting the appendicular skeleton. Treatment is typically with a combination of neo-adjuvant chemotherapy, tumour resection with limb reconstruction and post-operative chemotherapy. The current article reviews the role of magnetic resonance imaging (MRI) in the pre-operative assessment of high-grade central conventional osteosarcoma.

Skeletal Radiology

The initial MRI demonstrates a subcutaneous mass overlying the posterior facet of the right great... more The initial MRI demonstrates a subcutaneous mass overlying the posterior facet of the right greater trochanter, in broad communication with the iliotibial band. It is of isointense T1-weighted signal compared to skeletal muscle (Fig. 1a), hyperintense signal on STIR (Fig. 1b), and demonstrates peripheral enhancement post-contrast with a central stellate, linear region of non-enhancement (Fig. 2). Ultrasound demonstrates an avascular hypoechoic mass (Fig. 3). A photomicrograph (4× H&E) obtained after needle biopsy shows fibrous tissue with ischemic-type necrosis, granulation tissue, and degenerative cytological atypia (Fig. 4). A follow-up MRI study performed 21 months later demonstrated complete resolution of the mass with minor residual subcutaneous scarring (Fig. 5). Ischemic fasciitis, also known as atypical decubital fibroplasia, was first described by Montgomery et al. in 1992 [1]. It is a rare pseudo-sarcomatous fibroblastic proliferation, occurring at bony prominences or pressure points in elderly bed-ridden patients, with a female preponderance and peak age of incidence in the 8th–9th decades. It belongs to a group of other pseudo-sarcomatous lesions, including nodular fasciitis, proliferative fasciitis, and proliferative myositis [2]. Patients typically present with a 1 to 8 cm soft tissue mass of short duration (< 6 months), commonly involving soft tissue at the shoulders, ribs, sacrococcygeal region, and greater trochanters [3, 4]. Lesions are usually in the subcutis, although may involve the dermis leading to epidermal ulceration, striated muscle, and adjacent periosteum [4]. The etiology is unknown, although trauma is a precipitant. The pathogenesis is related to intermittent ischemia, leading to tissue necrosis and breakdown followed by a regenerative and reparative process [5, 6]. MRI typically demonstrates a poorly circumscribed subcutaneous soft tissue mass at a pressure point with peri-lesional soft tissue edema, which is isointense to skeletal muscle on T1-weighted sequences and hyperintense on T2-weighted sequences. There may be associated breach of the fascia. Following gadolinium administration, there is intense peripheral enhancement with a non-enhancing central component, reflecting necrosis. A necrotic abscess or soft tissue sarcoma can have a similar appearance [2, 4, 7]. Macroscopically, lesions appear ill-defined, multinodular, and tan in color [4]. Microscopically, the hallmark of ischemic fasciitis is zonal variations with central fibrinoid necrosis surrounded by proliferative fibroblasts and prominent vessels [3, 5, 8]. Kaneko et al. described a sonographic biphasic zonal pattern in ischemic fasciitis (avascular hypoechoic central zone and hypervascular hyperechoic external zone), which reflects this distinctive histological zonal appearance [8]. Ultrasound can also guide needle biopsy, which was performed in this case and confirmed the presence of ischemic fasciitis. In general, local excision is the treatment of choice, since if left untreated the lesionmay persist and is often painful. In this case, the mass spontaneously resolved. Kaneko et al. [8] and Lehmer et al. [9] also described spontaneous resolution in 6 months-2 years following behavioral modification. Following resection, local recurrence is rare and there are no reported cases of malignant transformation [3, 4]. Ischemic fasciitis is rare and can simulate soft tissue sarcoma clinically, radiologically, and histologically. As elderly, immobilized patients with poor operative and anesthetic risks are affected, awareness of this rare condition is essential to prevent unnecessary over-treatment. The case presentation can be found at https://doi.org/10.1007/s00256018-3030-5

Skeletal Radiology

Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily ari... more Solitary osteochondromas are common, benign hyaline cartilage-capped exostoses that primarily arise from the metaphyses of long and flat bones. Diaphyseal aclasis is an autosomal dominant condition resulting from EXT1 or EXT2 gene mutations and is characterized by multifocal osteochondromas. These can result in a wide spectrum of complications, such as skeletal deformity, neurological and vascular complications, adventitial bursa formation, fracture, and rarely malignant transformation to peripheral chondrosarcoma. In this review, we outline in detail the multimodality imaging features of DA and its associated complications.