Hakan Ilaslan

Clinical presentation and imaging of bone and soft-tissue sarcomas.

The clinical presentation of bone and soft-tissue sarcomas is varied. Constitutional symptoms are rare, and although bone sarcomas tend to be painful while soft-tissue sarcomas usually are not, there are exceptions to this general rule. A high index of suspicion is required for any unexplained mass with indeterminate imaging findings. Choosing the right imaging modality is critical to the diagnosis and management of patients with suspected sarcoma, and referring clinicians have a multitude of imaging options. After discovery of a malignant-appearing bone lesion by radiography, further imaging is obtained for better characterization of the lesion (typically with magnetic resonance imaging [MRI]) and for staging (typically with computed tomography of the chest). In contrast, radiographs are rarely helpful for evaluation of soft-tissue lesions, which almost always require MRI assessment.

Isolated Teres Minor Atrophy: Manifestation Of Quadrilateral Space Syndrome or Traction Injury to the Axillary Nerve?

This article prospectively determines through magnetic resonance imaging (MRI) the incidence of isolated teres minor atrophy and its gender and age distribution, and documents associated findings related to the rotator cuff, labroligamentous complex, and quadrilateral space. Two hundred seventeen consecutive shoulder MRI examinations performed over a 3-month period were prospectively reviewed and evaluated for isolated teres minor atrophy. Twelve (5.5%) patients had non-compressive isolated teres minor atrophy. Ninety-two percent (n=11) of these patients had rotator cuff or labroligamentous complex tears. No patients had an associated mass within the quadrilateral space. The average patient age was 60 years and 11 of the 12 patients were male. Isolated teres minor atrophy on MRI is most commonly seen in older patients who do not fit the expected clinical presentation of quadrilateral space syndrome. The anatomical relationship of the teres minor nerve to the joint capsule and the frequency of associated shoulder injuries in these patients raises the possibility of an association between humeral decentering and teres minor atrophy. Quadrilateral space syndrome would appear to be a very rare cause of isolated teres minor atrophy.

Selective Atrophy of the Abductor Digiti Quinti: An MRI Study

OBJECTIVE Entrapment of the first branch of the lateral plantar nerve is a well-recognized but diagnostically elusive cause of heel pain. The MR finding of selective atrophy of the abductor digiti quinti (ADQ) muscle has been reported as a marker of such entrapment. We performed a prospective study of consecutive patients undergoing foot and ankle MRI to determine the prevalence of ADQ atrophy and to examine the clinical symptoms of patients found to have ADQ atrophy. SUBJECTS AND METHODS A prospective study of all patients referred for ankle and foot MRI examinations was performed. Six hundred two patients were included in the study: 387 females and 215 males. All images were evaluated for the presence of selective fatty atrophy of the ADQ muscle. The clinical notes on all patients with findings of ADQ atrophy were analyzed for descriptions of symptoms leading to the MR examination, the presence of symptoms that might be related to nerve entrapment, and the influence on clinical management related to the MR finding of ADQ atrophy. RESULTS Thirty-eight of the 602 patients had selective fatty atrophy of the ADQ, 29 females and nine males. Only one patient had a clinical diagnosis of possible nerve entrapment before MR examination. MRI findings of ADQ atrophy altered clinical management in only one patient. CONCLUSION Selective fatty atrophy of the ADQ is not a rare finding on MR examination of the foot and ankle, being seen in 6.3% of all studies and in 7.5% of all studies in females. The clinical relevance of selective ADQ atrophy seen on MRI is uncertain.

Does the presence of focal normal marrow fat signal within a tumor on MRI exclude malignancy? An analysis of 184 histologically proven tumors of the pelvic and appendicular skeleton

ObjectiveThe aim of this study was to determine if the presence of focal normal bone marrow fat signal within a tumor on magnetic resonance imaging excludes malignancy.Materials and methodsOne hundred eighty-four histologically proven tumors with available magnetic resonance imaging (MRI) of the appendicular skeleton and pelvis from 184 patients were collected and reviewed at two separate institutions. There were 111 malignant and 73 benign tumors. Two radiologists at each institution, blinded to the diagnosis, reviewed the MRIs independently and reported the presence or absence of normal marrow fat signal within the tumor based upon T1-weighted imaging without fat suppression and T2-weighted imaging with fat suppression and/or short inversion-time inversion recovery (STIR). Discrepancies were then reviewed in consensus to determine the presence or absence of focal normal marrow signal. For each institution, a Fisher’s exact test was used to compare the frequency of focal normal marrow fat signal in benign and malignant tumors. This comparison was performed for each reader, as well as for the consensus reading at each site. Positive and negative predictive values were also calculated for each reader, as well as the consensus reading at each site. Fisher’s exact test was also used to compare the frequency of intratumoral fat in benign and malignant lesions for the pooled sample. Bayes theorem was used to calculate the positive and negative predictive values for the pooled consensus data. Ninety-five percent confidence intervals were constructed for the pooled estimates using a bootstrapping algorithm.ResultsThere was good interobserver reliability of 95.3% and 96.7% at sites 1 and 2, respectively. There were three discrepancies (one malignant and two benign) at site 1 and four discrepancies (two malignant and two benign) at site 2. Reader consensus at site 1 identified normal marrow fat signal within 1 of 50 (2.0%) malignant and three of 14 (21.4%) benign tumors. Findings were statistically significant with a p value of 0.030. The positive predictive value (PPV) and negative predictive value (NPV) at site 1 was 81.7% and 75.0%, respectively. Reader consensus at site 2 identified normal marrow fat signal within three of 61 (4.9%) malignant and 14 of 59 (23.7%) benign tumors. Findings were statistically significant with a calculated p value of 0.004. The PPV and NPV at site 1 was 56.3% and 82.4%, respectively. For the pooled consensus, the frequency of intratumoral fat in benign lesions (17/73, 23.3%) is significantly greater than the frequency in malignant lesions (4/111, 3.6%), p < 0.001.ConclusionThe presence of focal normal marrow signal within a tumor is highly suggestive of a benign tumor.

Deltoid muscle and tendon tears in patients with chronic rotator cuff tears.

PurposeTo describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery.Materials and methodsDeltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues.ResultsThere were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients.ConclusionTears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear.

Imaging of primary malignant bone tumors (nonhematological).

Primary malignant bone tumors are uncommon and are diagnosed typically based on radiographic and microscopic findings combined with clinical and demographic features. CT and MR imaging scans are useful in further staging the tumors by determining intraosseous and extraosseous spread.

Decubital Ischemic Fasciitis: Clinical, Pathologic, and MRI Features of Pseudosarcoma

OBJECTIVE The purpose of this report is to describe clinical, pathologic, and MRI findings on decubital ischemic fasciitis, which is a rare soft-tissue tumor sarcoma simulator. CONCLUSION Decubital ischemic fasciitis is a reactive, nonneoplastic lesion typically seen in older debilitated patients at pressure points. Because this lesion simulates soft-tissue sarcoma, both clinically and histologically, it is important to recognize the MRI features and limit misdiagnosis of sarcoma.

Imaging findings, prevalence and outcome of de novo and secondary malignant fibrous histiocytoma of bone

ObjectiveTo evaluate the radiographic and magnetic resonance (MR) imaging features of primary and secondary malignant fibrous histiocytoma in bone and determine the demographics, prevalence and outcome of patients with this tumor.Materials and methodsA retrospective search of files from two institutions identified 28 patients with malignant fibrous histiocytoma (MFH) of bone. Microscope slides were reviewed to confirm diagnosis and identify any pre-existing lesions. Medical records were reviewed with respect to patients’ demographic characteristics and outcomes.ResultsRadiographic features demonstrated an aggressive osteolytic lesion with a permeative pattern of bone destruction. Periosteal reaction was seen in three of 13 lesions. T1-weighted images (T1WIs) demonstrated signal intensity iso- to slightly hyperintense to muscle. T2-weighted images (T2WIs) demonstrated mildly higher signal intensity than that of muscle. The 5-year survival rate was 53%. The tumor arose secondarily in pre-existing lesions in 43% of patients. Metastases occurred in 46% of patients during the course of the disease, with pulmonary and osseous metastases being the most common.ConclusionSecondary MFH of bone was slightly less common than primary MFH and had a prognosis similar to that of primary MFH of bone. MR imaging showed variable and somewhat unusual low to intermediate T2 signal characteristics for a radiographically malignant osteolytic lesion.

Rheumatoid Arthritis: Evaluation with Contrast-enhanced CT with Digital Bone Masking

The purpose of this HIPAA-compliant study was to prospectively evaluate the feasibility of contrast material-enhanced computed tomography (CT) with digital bone masking for the evaluation of synovitis and tenosynovitis in patients with rheumatoid arthritis. Four patients with rheumatoid arthritis and findings at magnetic resonance (MR) imaging were evaluated after informed consent for this institutional review board-approved study was obtained. To improve the conspicuity of synovial enhancement, postcontrast CT was performed with a relatively low kilovoltage and high iodine concentration and precontrast images were used as a subtraction mask to eliminate high-attenuation cortical bone contours. Moderate to high agreement between CT and MR imaging findings for synovitis and tenosynovitis was demonstrated, which suggests that this technique may be an acceptable alternative to MR imaging in the evaluation of rheumatoid arthritis.

Imaging of Sarcomas of Pelvic Bones

Sarcomas are the most common nonhematologic primary malignancies of bones in the pelvis. Chondrosarcoma, osteosarcoma, and Ewings sarcoma are the most common sarcomas to originate from the pelvic bones. Various imaging modalities such as magnetic resonance imaging and computed tomography play an important role in the detection, characterization, and staging of these lesions. Biopsy, usually performed with imaging guidance, is essential for the histologic diagnosis of these tumors and for planning therapeutic options. Despite considerable advances in treatment options, sarcomas in the pelvic bones generally are associated with poorer outcomes than sarcomas in the appendicular skeleton because of the larger size of the lesions at the time of discovery and the difficulty of obtaining a wide surgical resection margin. In this review, we discuss the various types of pelvic bone sarcomas and the role of imaging in patients with these lesions.