Juvenile granulosa cell tumor associated with Ollier disease.

Prior case reports have described synchronous ovarian juvenile granulosa cell tumor (JGCT) and enchondromatosis in patients with Ollier disease and Maffucci syndrome. We present a case of a juvenile granulosa cell tumor with an IDH1 somatic mutation identified in the ovarian tissue in a 15-year-old female who presented with abnormal vaginal bleeding, several months of irregular menses, and a large multicystic adnexal mass. Multiple mixed lytic and sclerotic lesions were identified in the bones of the pelvis on imaging studies obtained during the work-up of her abdominal mass. Like previous reports in patients with undiagnosed enchondromatosis, these lesions were presumed to represent skeletal metastases; however, biopsy tissue revealed a hyaline cartilage neoplasm. Subspecialty review of the imaging findings revealed imaging features classic for Ollier disease involving the flat bones of the pelvis. It is important for radiologists to be familiar with the association between enchondromatosis and JGCT. When a female patient with enchondromatosis presents with a large, unilateral, mixed solid-cystic ovarian mass, the diagnosis of JGCT can be suggested. Alternatively, when a patient is diagnosed with JGCT, any skeletal lesions should be scrutinized for imaging features that suggest a hyaline cartilage neoplasm to avoid the misdiagnosis of skeletal metastases in a patient with previously undiagnosed Ollier disease or Maffucci syndrome. To our knowledge, this is the second reported confirmed case of an IDH1 somatic mutation identified in the ovarian tissue of a JGCT in a patient with Ollier disease.

Bone Tumors: Common Mimickers.

Mimics of primary and secondary bone tumors may result from a variety of processes. These can range from normal variants or developmental lesions that require no further work-up, to findings that require more urgent management, or may be indicative of a more serious systemic disease that necessitates further evaluation and treatment. It is important to be familiar with the spectrum of bone tumor mimics to avoid unnecessary tests, minimize patient morbidity, and reduce patient anxiety. This article discusses numerous nonneoplastic bone tumor mimickers, including their characteristic multimodality imaging features, differential diagnosis, and important aspects with which radiologists should be familiar.

Eccrine angiomatous hamartoma: First case in the cytology literature.

A 34-year-old male presented with a swelling on the volar surface of the third digit of his right hand. This swelling was associated with pain and erythema. Ultrasound-guided needle biopsy was performed. Cytologic and histologic preparations together confirmed the diagnosis of a rarely encountered mixed epithelial and mesenchymal proliferation, an eccrine angiomatous hamartoma. To our knowledge, this case is the first to illustrate the cytomorphologic features of this rare lesion.

Quantitative Musculoskeletal Tumor Imaging.

The role of quantitative magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) techniques continues to grow and evolve in the evaluation of musculoskeletal tumors. In this review we discuss the MRI quantitative techniques of volumetric measurement, chemical shift imaging, diffusion-weighted imaging, elastography, spectroscopy, and dynamic contrast enhancement. We also review quantitative PET techniques in the evaluation of musculoskeletal tumors, as well as virtual surgical planning and three-dimensional printing.

Extraneural perineurioma: CT and MRI imaging characteristics.

OBJECTIVE: To examine the CT and MRI characteristics of extraneural perineuriomas. MATERIALS AND METHODS: With IRB approval, our institutional imaging database was retrospectively reviewed for cases of pathologically proven extraneural perineuriomas. CT and MRI features were recorded, correlative imaging analyzed, and the electronic medical record cross-referenced. RESULTS: We identified ten patients [(seven males, three females, mean age 49.4 ± 18.3 years (range, 16-70 years)]. All cases were pathologically confirmed. Nine cases were conventional soft tissue extraneural perineuriomas, including one with "reticular" features and one with histologic features of malignancy; the tenth case contained admixed Schwann cells (hybrid perineurioma/schwannoma). Six out of ten patients underwent CT and ten of ten MRI evaluation. Nine out of ten MRIs were performed with IV contrast. Five lesions were subcutaneous, four intermuscular, and one intramuscular. Mean lesion diameter was 4.3 ± 2.7 cm (range, 0.9-10.2 cm). Nine out of ten lesions were well circumscribed; one had irregular margins. On CT, five of six were hypodense and one isodense compared to skeletal muscle. Most lesions were T1 isointense (5/10) or hypointense (4/10) and T2 hyperintense (7/10) relative to skeletal muscle, and demonstrated solid enhancement (6/9). There was no evidence of muscular denervation on any MRI exam, and a nerve of origin was identified in two out of ten cases. CONCLUSIONS: Extraneural perineuriomas have a distinctly different imaging appearance from intraneural perineuriomas, manifesting as rounded or ovoid soft tissue masses, without evidence of muscular denervation, and usually without an apparent nerve of origin. Because these features mimic other benign and malignant soft tissue lesions, including sarcomas, biopsy or excision is needed for definitive diagnosis.

Osteomeniscal Impact Edema (OMIE): Description of a Distinct MRI Finding in Displaced Flap Tears of the Medial Meniscus, with Comparison to Posterior Root Tears.

Bone marrow edema (BME) can be a late finding in osteoarthritis or a sign of subchondral insufficiency. The purpose of this study was to describe the magnetic resonance imaging (MRI) finding we refer to as "osteomeniscal impact edema" (OMIE), or reactive BME adjacent to a displaced meniscus flap tear. In addition, this edema pattern is compared with a control group of medial meniscus posterior root tears (MMPRT) with subchondral insufficiency edema. MRI records from 2000 to 2017 were retrospectively reviewed for studies that showed the presence of a medial meniscus displaced flap tear and an adjacent area of BME. The selected MRIs were matched to an equal number of MMPRT MRI studies. All MRI studies were assessed for cartilage surface grade using the modified Outerbridge classification system and for the extent of accompanying structural abnormalities using the whole-organ magnetic resonance imaging score. Descriptive statistics and hypothesis testing were utilized to compare the MRI findings between groups. Twenty-two flap tear (OMIE group) patients with a mean age of 57 (SD: 15) and 22 root tear (MMPRT) group patients with a mean age of 61 (SD: 10) were included. MRIs in the OMIE group showed a distinctive pattern of focal, peripheral edema adjacent to the meniscus flap tear, compared with more diffuse, central edema in the MMPRT group. Quantitatively, MRIs of the MMPRT group showed significantly worse mean femoral Outerbridge scores (3.72 vs. 2.68, p < 0.0001), more severe central (1.63 vs. 0.5, p = 0.0007) and posterior (0.31 vs. 0.0, p = 0.04) subchondral edema grades, and a higher incidence of tibial subchondral fractures (3 vs. 0, p = 0.036). Meniscus flap tears may present with a distinct MRI pattern of focal, adjacent, peripheral edema, which we refer to as OMIE. Patients with meniscus flap tears showed significantly less arthritic change, lower subchondral edema grades, and a lower incidence of insufficiency fractures and subchondral collapse compared with the diffuse overload edema pattern found with root tears. The Level of Evidence for this study is III.

Chondrosarcoma arising within synovial chondromatosis of the lumbar spine.

Synovial chondromatosis is an uncommon benign neoplasm that usually affects large appendicular joints and only rarely the spine. There are only a few small series and case reports documenting malignant transformation of synovial chondromatosis into secondary chondrosarcoma, typically within the hip in the setting of recalcitrant disease and multiple recurrences. Chondrosarcoma arising in synovial chondromatosis of the spine is exceedingly rare, with only one previously published case report involving the craniocervical junction. We present a case of chondrosarcoma arising within synovial chondromatosis of the lumbosacral spine, with the diagnosis made at the time of initial presentation. We describe the clinical, imaging, and histopathological findings and review diagnostic criteria for this difficult diagnosis.

18F-FDG PET/CT and MRI features of myxoid liposarcomas and intramuscular myxomas.

OBJECTIVE: To examine the imaging characteristics of intramuscular myxomas (IM) and myxoid liposarcomas (MLS) on 18F-FDG PET/CT and MRI. MATERIALS AND METHODS: With IRB approval, our institutional imaging database was searched for pathologically proven IM and MLS evaluated by 18F-FDG PET/CT and MRI. PET/CT and MRI imaging characteristics were recorded and correlated with pathologic diagnosis. RESULTS: We found eight patients (2 M, 6 F) with IM (mean age 65.6 ± 10.4 years) and 16 patients (7 F, 9 M) with MLS (mean age 42.8 ± 16.3 years). MRI was available in 7/8 IM and 15/16 MLS patients. There was no significant difference between the two groups in SUVmax (IM 2.7 ± 0.8, MLS 3.0 ± 1.0; p = 0.35), SUVmean (1.7 ± 0.4, 1.5 ± 0.5; p = 0.40), total lesion glycolysis (101.8 ± 127.3, 2420.2 ± 4003.3 cm3*g/ml; p = 0.12), metabolic tumor volume (62.3 ± 71.1, 1742.9 ± 3308.0 cm3; p = 0.17) or CT attenuation (p = 0.70). MLS occurred in younger patients (p = 0.0015), were larger (16.4 ± 8.2 vs. 5.6 ± 2.5 cm; p = 0.0015), more often T1 hyperintense (p = 0.03), with nodular enhancement (p = 0.006), and macroscopic fat on CT (p = 0.0013) and MRI (p = < 0.001) compared to myxomas. CONCLUSIONS: IM and MLS most commonly demonstrate low-grade FDG activity and overlapping metabolic measures on PET/CT. MRI is useful in differentiation, but MLS can present without macroscopic fat on MRI, underscoring the importance of radiologic-pathologic correlation for accurate diagnosis.

Arthritis Progression on Serial MRIs Following Diagnosis of Medial Meniscal Posterior Horn Root Tear.

Medial meniscus posterior root tears (MMPRTs) are a significant source of pain and dysfunction. The purpose of this study was to evaluate changes in the medial compartment of the knee over time following the diagnosis of a MMPRT on MRI. A retrospective review of the institutional database was performed for patients with an initial MRI diagnosis of a MMPRT. Patients were included if they had a subsequent follow-up MRI on the same knee. Patients with surgical intervention, including debridement or repair, were excluded. MRIs were evaluated by two board-certified musculoskeletal radiologists. MMPRTs were defined using the LaPrade classification, and the medial compartment articular cartilage was graded using the modified Outerbridge classification. MRIs were reviewed for meniscus extrusion, subchondral bone edema, and insufficiency fractures. Patients were divided into two groups for the analysis to account for differences in MRI time intervals. Group 1 had a follow-up MRI within 12 months of initial imaging (subacute group) and Group 2 had a follow-up MRI greater than 12 months after initial imaging (chronic group). Forty-one knees and 82 MRIs were analyzed, including 20 knees/40 MRIs (13 females, 7 males) in the subacute group and 21 knees/42 MRIs (14 females, 7 males) in the chronic group. Subacute patients had a mean age of 59.5 ± 8.8 years and a mean interval of 4.8 ± 2.6 months between MRIs compared with 53.6 ± 11.0 years and 38.2 ± 20.8 months, respectively, for the chronic group. Meniscal extrusion, femoral modified Outerbridge grade, and tibial modified Outerbridge grade worsened between initial and final MRI in both groups (p < 0.05). In both groups, there were no significant differences between initial and final MRIs with regard to the LaPrade classification, insufficiency fracture, or subchondral cysts of the tibia. Progressive meniscus extrusion and medial compartment articular cartilage degeneration were seen in patients with MMPRTs within a year from diagnosis.

Extra-adrenal myelolipoma and extramedullary hematopoiesis: Imaging features of two similar benign fat-containing presacral masses that may mimic liposarcoma.

OBJECTIVE: To describe the imaging characteristics of extra-adrenal myelolipoma and mass-forming extramedullary hematopoiesis (EMH) occurring in the presacral region. MATERIALS AND METHODS: Retrospective review between 1980 and 2015 revealed 11 patients with biopsy-proven presacral extra-adrenal myelolipoma and 11 patients with presacral EMH and radiologic imaging studies. RESULTS: All cases of both myelolipoma and EMH directly abutted the anterior sacrum and were centered on the midline. Myelolipomas were round or bilobed (8/11), or were multilobulated in appearance (3/11). On CT, margins could be smooth or ill defined. On MRI, all masses were well-marginated with evidence of a "capsule". All myelolipomas showed evidence of macroscopic fat on both CT and MRI with scattered hazy and nodular soft tissue components. On MRI, all cases showed areas of high T1 signal intermixed with areas of intermediate T1 signal. On T2, all cases showed areas of low and high T2 signal. Enhancement was usually minimal or mild. Most EMH cases had a well-defined round, bilobed or macro-lobulated presacral mass (9/11); 2/11 cases were ill-defined. On CT, when a dominant fatty component was present, the soft tissue components had hazy and nodular features, similar to myelolipoma. On MRI, the masses demonstrated intermediate T1 signal, isointense to skeletal muscle with varying amounts of hyperintense T1 signal. On T2-weighted images, 3 of 4 cases showed areas of mildly hyperintense T2 signal with varying amounts of dark signal. All patients with clinically or biopsy-proven EMH had a hematologic or myeloid disorder. CONCLUSION: Presacral myelolipoma and presacral EMH are two benign fat-containing masses that can present as discrete, often encapsulated, lipomatous masses with varying amounts of non-lipomatous soft tissue components and should be considered in the differential diagnosis of a well-defined fat-containing presacral mass.

Malignant transformation of polyostotic fibrous dysplasia with aberrant keratin expression.

Malignant transformation of fibrous dysplasia (FD) is exceedingly rare, occurring in less than 1% of all FD cases, and has been described in both monostotic and polyostotic forms of this entity. We report a case of a large proximal femur mass arising in a 45-year-old man. The biopsy revealed a high-grade pleomorphic malignancy that focally expressed multiple keratins. Based on the presence of keratin immunoreactivity, the morphologic differential diagnosis included metastatic sarcomatoid carcinoma. However, review of the clinical information revealed a history of polyostotic FD, and imaging findings were compatible with malignant transformation of FD. The resected neoplasm was biphasic and composed of areas of conventional FD admixed with a high-grade pleomorphic malignancy. Activating GNAS mutations were identified in both components. To the best of our knowledge, this is the first description of keratin expression in malignant transformation of FD.

Imaging features of synovial chondromatosis of the spine: a review of 28 cases.

OBJECTIVE: To describe the radiographic, CT, and MRI appearance of synovial chondromatosis of the spine. MATERIALS AND METHODS: Radiology and pathology databases were searched for cases of spinal synovial chondromatosis from 1984 through 2013, yielding 29 patients (16 males, 13 females). The average age was 45 years. Twenty-eight patients had imaging studies available for review including seven radiographs, two myelograms, 13 CT, and 23 MRI exams. RESULTS: Cases were located in the cervical spine (16), thoracic spine (6), lumbar spine (6), and sacrum (1). Twenty-two cases (79%) had an epidural component. Eighteen (64%) had a neural foraminal component. Sixteen (57%) had a paraspinal component. The mass abutted a facet joint in 96% of cases. Nearly all (96%) showed a normal facet joint without internal erosive changes. Most (79%) showed evidence of chronic extrinsic bony erosion, usually involving the surface of the facet. Only 44% had calcifications as a dominant finding. Most patients (88%) had evidence of neural compression. On T1-weighted MRI, 80% showed intermediate or a combination of intermediate and dark signal. On T2-weighted images, 89% showed heterogeneous signal with discrete areas of dark signal. The majority (83%) showed a peripheral pattern of enhancement, usually peripheral nodular. CONCLUSIONS: Synovial chondromatosis should be considered in the differential diagnosis when evaluating an epidural and/or paraspinal mass near a facet joint, especially when there is evidence of chronic extrinsic bone erosion, dark signal or nodules on T1 and/or T2, and nonenhancing fluid or myxoid signal centrally with thin or nodular peripheral enhancement.

Radiographic, CT, and MR imaging features of dedifferentiated chondrosarcomas: a retrospective review of 174 de novo cases.

Up to 11% of chondrosarcomas may undergo regional anaplastic change, resulting in a high-grade noncartilaginous sarcoma arising within a typically low-grade chondrosarcoma. Known as dedifferentiated chondrosarcomas, these tumors are highly malignant with a very poor prognosis. The most important factor affecting survival is an accurate preoperative diagnosis. Therefore, the ability to predict the possibility of dedifferentiation in a malignant cartilage tumor on the basis of imaging findings is critical to ensure adequate tumor sampling at the time of biopsy. Imaging findings at radiography, computed tomography (CT), and magnetic resonance (MR) imaging in 174 patients with dedifferentiated chondrosarcoma were reviewed to determine whether there are radiologic features that can help predict dedifferentiation. On approximately one-third of the radiographs, one-third of the MR images, and one-half of the CT scans, the tumors demonstrated bimorphic features (ie, distinctly different tumor features juxtaposed within the lesion), most frequently a dominant lytic area adjacent to a mineralized tumor at radiography and a large, unmineralized soft-tissue mass associated with an intraosseous chondroid-containing tumor at CT and MR imaging. In the initial evaluation of patients with a primary bone tumor, thorough evaluation of the radiologic features of the entire tumor is critical.