Lymphadenopathy at the medial epitrochlear region in cat-scratch disease.

Our objective was to describe the imaging features of lymphadenopathy at the medial epitrochlear region as frequently seen in cat-scratch disease (CSD) and to compare these features with those seen in non-CSD. Ten patients (four males and six females) presented with a subcutaneous soft tissue mass at the medial epitrochlear region. Three patients were younger than 15 years. Magnetic resonance imaging was performed in all patients. All lesions turned out to be regional lymphadenopathy instead of soft tissue neoplasm. They were caused by benign disorders in eight cases, including seven CSD and one other infection, and in two cases by metastatic disease. All lesions, except for three benign ones, were solitary. On MRI, high signal intensity (SI) strands in the surrounding soft tissue on T2-weighted images (WI) were present in all cases. Three cases of CSD showed homogeneous SI on both T1- and T2WI. After contrast administration, a moderate, homogeneous enhancement was seen. The other seven lesions, except for one metastasis, had both solid and liquid components. Liquid components showed high SI on T2WI without enhancement, whereas solid components had intermediate SI on T2WI and marked enhancement after contrast administration. Pathological findings in seven patients, including four with CSD, supported the tentative diagnosis made on MRI. One of two patients with CSD had positive serological test. Cat-scratch disease is a major cause of a soft tissue swelling at the medial epitrochlear region. Identification of lymphadenopathy and its presentation on MRI may be helpful in eliciting an animal-scratch history and achieving diagnostic and therapeutic aims in patients without primary cancer.

Reliability of measuring volume by different methods for tumors of the musculoskeletal system.

In the present study different methods for determining the volume of a tumor were evaluated. For 12 models, the real volume, the volume according to measurement of the surface area on MRI, an ellipsoid and a cylindrical approximation of the volume, as well as the maximum diameter, were determined. There appeared to be a good correlation between all calculated volumes and the real volume. The error (mean: 17%) and the standard deviation (SD: 14%) on this error were smallest if the volume was determined by means of determination of the surface area. The ellipsoid approximation resulted in a smaller error (mean: 0%) but a higher standard deviation (SD: 27%). The cylindrical approximation resulted in unacceptable deviations (mean: 51%; SD: 40%). Volume was significantly related to the maximal diameter to the power of 2.3. Volume calculated according to this power resulted in an error of 18%. Standard deviation in this case however was unacceptable (SD: 89%). Volume calculation based upon the determination of the surface area has given the best and most reliable results. Ellipsoid approximation was less reliable, but faster and cheaper. Cylindrical approximation was unacceptable. Size, expressed as maximal diameter of the tumor, was also unacceptable as a parameter for volume.

Low-grade chondrosarcoma vs enchondroma: challenges in diagnosis and management.

A 28-year-old man presented with a swelling at the right thoracic wall. Computed tomography showed an aggressive process involving the cortex of the rib with concomitant soft tissue mass. However, a needle biopsy specimen revealed an enchondroma and consequently the physician decided to apply a "wait-and-see" strategy. After 3 years of careful follow-up by MR imaging, the patient complained of subtle enlargement of the lesion, which was later confirmed on repeated CT scan. Despite an aggressive appearance on control MR imaging, histopathological examination after incisional biopsy could not differentiate between enchondroma and low-grade chondrosarcoma. Wide excision including previous biopsy trajectory was performed. Diagnosis of a low-grade (grade I) chondrosarcoma was made on findings of the excisional specimen and seeding of cartilage tissue along the previous incisional biopsy trajectory was found.

Thyroid acropachy: correlation of imaging and pathology.

Thyroid acropachy is a rare manifestation of autoimmune thyroid disease, in the form of soft tissue swelling of the hands and feet with insidious onset, associated with clubbing and characteristic periosteal reactions. It is usually part of a syndrome consisting of a typical triad of thyroid acropachy, exophthalmos, and pretibial myxedema. The purpose of this case report is to demonstrate the imaging features of this typical triad in a 65-year-old-woman. This case is the first in which the MRI features of thyroid dermopathy are documented.

MR features of peripheral nerve sheath tumors: can a calculated index compete with radiologist's experience?

The aims of this study were, firstly, to provide a formula (neurogenic index) based on MR characteristics used in daily routine for predicting whether a soft tissue tumor is neurogenic or not, secondly, to test prospectively the performance of this formula, and thirdly, to compare this performance with that of radiologists experienced in MR imaging of soft tissue tumors. Retrospectively, MR images of 70 neurogenic and 70 non-neurogenic soft tissue tumors were evaluated in random order by two teams of two observers each. A neurogenic index (NI) was calculated based on those MR parameters that showed no or minor interobserver variability. Subsequently, three investigators in concert used the NI in a validation group of 15 neurogenic and 22 nonneurogenic soft tissue tumors. The same team, based on their own experience, tried to differentiate in the same validation group neurogenic from non-neurogenic soft tissue tumors. This was expressed in a subjective score (SS). Sensitivity, specificity, and predictive values were calculated. NI comprised spread (intra- or extracompartmental), distribution, fluid-fluid levels, homogeneity on T2-weighted images (WI), highest signal intensity (SI) on T1WI, lowest SI on T2WI, and delineation on T2WI. In the validation group, NI had a sensitivity of 88.6%, a specificity of 52.0%, a positive predictive value (PPV) of 54.1%, and a negative predictive value (NPV) of 84.6% for neurogenic tumors. The subjective score SS was superior and had a sensitivity of 93.3%, a specificity of 77.2%, a PPV of 73.7%, and a NPV of 94.4%. Our NI was less accurate than the SS; however, the low number of false-negative diagnoses for neurogenic tumors warrants continued efforts in development of neural networks.

Sclerosing bone dysplasias: genetic and radioclinical features.

Although knowledge of basic genetics in the field of sclerosing bone dysplasias is progressing, the radiologist still plays a pivotal role in the diagnosis of this relatively poorly understood group of disorders. Based on a target site approach, these anomalies are classified into three groups. Within each group, further differentiation can be made by distinctive clinical findings and by mode of inheritance: (a) dysplasias of endochondral bone formation: osteopetrosis (Albers-Schönberg disease), pycnodysostosis, enostosis, osteopoikilosis, osteopathia striata (Voorhoeve disease); (b) dysplasias of intramembranous bone formation: progressive diaphyseal dysplasia (Camurati-Engelmann disease) and variants, hyperostosis corticalis generalisata (Van Buchem disease) and variants; and (c) mixed sclerosing dysplasias: melorheostosis (Leri disease) and overlap syndromes.

MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): a multicenter correlative MRI-pathology study of 21 cases and literature review.

OBJECTIVE: To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts). DESIGN AND PATIENTS: MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study. RESULTS: On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody. CONCLUSIONS: Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well-defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images.

Desmoplastic fibroma of bone: MRI features.

Desmoplastic fibroma of bone is a very rare benign tumor, which may be locally aggressive. In contrast to the well-documented radiological appearance, the literature on MR imaging features of this tumor is scarce. The MR imaging characteristics in our case are compared to those previously reported. Although there is a considerable overlap in the MR imaging features with other bone tumors, an interesting MR feature of desmoplastic fibroma is the presence of low to intermediate signal intensity foci on T2-weighted images, which radiographically does not correspond to calcifications. This feature may help narrow the differential diagnosis.

[Magnetic resonance imaging of soft tissue tumors of the hand and wrist]. / L'imagerie par résonance magnétique des tumeurs des tissus mous de la main et du poignet.

We will discuss the imaging characteristics of soft tissue tumors of the hand and wrist, especially the magnetic resonance imaging findings, since MRI has proven to be the gold standard for characterization of soft tissue tumors. Our series consists of 71 tumors of the hand and wrist, that were examined by magnetic resonance imaging. Fourty-four lesions were benign, 7 malignant, and 20 lesions were pseudotumoral masses. The signal characteristics often allow to make a correct diagnosis or to narrow down the list of differential diagnoses. It also allows to determine the extent of the lesion more accurately.

Proteus syndrome: MRI characteristics of plantar cerebriform hyperplasia.

Proteus syndrome is a rare congenital hamartomatous syndrome with a variety of abnormalities. It shares many features with other congenital hamartomatous disorders, but cerebriform hyperplasia of the soles and the palms is known as a quite distinctive characteristic in the dermatologic literature. The purpose of this case report is to demonstrate the MRI features of plantar cerebriform hyperplasia in a 9-year-old boy with known Proteus syndrome.

Magnetic resonance imaging of soft tissue tumors.

This article outlines the ability of MR imaging in staging, grading, tissue characterization, and posttherapeutic surveillance of soft tissue tumors. Well-known staging parameters, such as extent, relationship with adjacent structures, and detection of intralesional necrosis, are used in the MR protocol for locoregional staging. Bone scintigraphy and high-resolution CT scan of the lungs are best methods for ruling out metastatic spread. A variety of (solitary or combinations of) grading parameters are described in the radiological literature. The role of MR imaging is to afford recognition of these lesions that need further aggressive work-up, excluding all others. Despite controversial reports, the definite role of MR imaging in grading of soft tissue tumors seems to become established. As for grading, a lot of individual imaging characteristics used for tissue characterization have low sensitivity, but combinations of parameters (age, site, signal intensities) are more useful and often allow to predict a specific diagnosis or to narrow down the list of differential diagnoses. Local recurrences of soft tissue tumors are frequent and can be detected accurately by an easy-to-use MR algorithm.

Metachronous eosinophilic granuloma of bone.

We present the case of a 4-year-old girl who developed a metachronous osseous lesion of the left distal femur five months after successful surgical treatment of an eosinophilic granuloma in the left proximal femur. After treatment of the second lesion with curettage, no further recurrence occurred during a follow-up interval of 17 months. Radiologists should be aware that additional eosinophilic granulomas of bone, occurring in up to four years after the initial diagnosis, should still be interpreted as a localized form of Langerhans'cell histiocytosis with a more favorable prognosis than the multifocal disseminated form, with involvement of organ systems other than the skeletal system.

Hypertrophy and pseudohypertrophy of the lower leg following chronic radiculopathy and neuropathy: imaging findings in two patients.

Enlargement of the ipsilateral muscle compartment is an exceptional finding in patients with chronic radiculopathy, peripheral nerve injury, anterior horn cell diseases, or acquired peripheral neuropathy. We report radiographic, ultrasonographic, CT and MRI findings in a patient with chronic S1 radiculopathy and another with chronic neuropathy of the common fibular nerve (L4-S2), both presenting with painless enlargement of the calf muscles.