Masataka Abe

Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Abstract Objective.To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient’s age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient’s age, duration of symptoms, and location of lesions were evaluated by Pearson’s correlation coefficient and analysis of variance. Results.Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient’s age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema.

Posterior interosseous nerve palsy caused by parosteal lipoma of proximal radius

Abstract Lipomas are common benign soft tissue tumors which tend to be indolent, and symptoms caused by nerve compression are unusual. However, a parosteal lipoma, occurring adjacent to the proximal radius may easily cause paralysis of the posterior interosseous nerve because of a specific anatomical relationship of these structures in that area. Two cases of parosteal lipoma of the proximal radius causing paralysis of the posterior interosseous nerve are reported. CT and MR imaging demonstrate the characteristic fatty mass around the radius and are specific in making the diagnosis. Surgical excision should be promptly performed to ensure optimal recovery from the nerve paralysis.

Reactive heterotopic ossification: Its patterns on MRI

The purpose of this report is to analyze common features of reactive heterotopic ossification, zone phenomenon and involution. Eleven cases evaluated with plain radiography and MRI were classified based on the location: intramuscular, periosteal, and intermediate (mainly the insertion site of muscles). Zone phenomenon tends to be complete in the intramuscular type and incomplete in the periosteal type. Involution is also more evident in the intramuscular type.

Magnetic resonance imaging of pseudomalignant osseous tumor of the hand.

Noninfectious, nonneoplastic reactive processes of the hand, such as myositis ossificans circumscripta, pseudomalignant osseous tumor of soft tissue, and florid reactive periostitis, appear similar radiologically and histologically and are often difficult to differentiate. Magnetic resonance (MR) findings in two such lesions are reported. The extensive reactive change in the extraosseous soft tissue and the bone marrow and the relatively small extent of ossification may be characteristic. Although low-grade infection and small osseous neoplasms with reactive changes, such as osteoid osteoma, may still remain possible causes, MR imaging provides essential evidence for including noninfective, nonneoplastic reactive processes of uncertain cause in the list of differential diagnoses.

MRI of myositis ossificans circumscripta

Myositis ossificans circumscripta (or pseudomalignant osseous tumor of soft tissue) may be confused with malignant neoplasms if there is no clear history of trauma. Two cases are presented in which magnetic resonance imaging (MRI) clearly demonstrates disproportionally extensive abnormal signal intensity along the course of muscle fibers. Although the specificity of this finding is uncertain, MRI enhances the level of confidence in diagnosing myositis ossificans.

Case report 545

This 62-year-old woman was admitted to hospital in August 1983 with a three-week history of numbness in the upper extremities. The family history was negative, while the patients medical history was unremarkable except for pulmonary tuberculosis about thirty-five years previously. Examination revealed increased reflexes in both triceps, brachioradialis and legs with positive Hoffmanns and Wartenbergs sign. Babinskis sign was not present. Muscle atrophy was not prominent,

Simultaneous avulsion of patellar apexes bilaterally in a hemodialysis patient.

A case of simultaneous bilateral avulsion of the patellar apexes is reported. Plain radiography showed bilateral patella alta, but MR imaging was diagnostic. Weakness of the tendo-osseous junction due to secondary hyperparathyroidism and additional chronic inflammatory changes due to repeated microtrauma were considered to be the cause of the rupture.

Fluid-fluid levels in cavernous hemangioma of soft tissue

Five cases of cavernous hemangioma with fluid-fluid levels on magnetic resonance imaging and/or computed tomography are reported. The signal characteristics were those of blood and histological analysis of the fluid-fluid levels showed that they were blood-filled cavities in the tumor. Although this finding itself is not specific, it may help in confirming the diagnosis of cavernous hemangioma.

Stimulation of the Synthesis of Histamine and Putrescine in Mice by a Peptidoglycan of Gram-Positive Bacteria

To clarify the base of in vivo biological activities of peptidoglycans of Gram‐positive bacteria, the effects of a polysaccharide peptide of Staphylococcus epidermidis peptidoglycan (SEPS) on the synthesis of histamine and putrescine in BALB/c mice were examined and compared with those of a lipopolysaccharide (LPS or endotoxin) of Gram‐negative bacteria. Within a few hours after its injection into BALB/c mice, SEPS induced histidine decarboxylase (HDC), the enzyme forming histamine, in the liver, lung, spleen and bone marrow, and ornithine decarboxylase (ODC), the enzyme forming putrescine, in the tissues except for the lung. SEPS induced HDC activity even in mast cell‐deficient mice and in nude mice. These effects of SEPS were essentially the same as those of LPS. However, the dosage of SEPS capable of inducing HDC and ODC was much higher (100 to 1,000 times) than that of LPS. We have reported that C3H/HeN mice are resistant to SEPS in producing acute arthritis, and their productions of IL‐1 and prostaglandin E2 are less than BALB/c mice sensitive to producing acute arthritis. In the present study, it was also found that C3H/HeN mice were markedly resistant to SEPS in inducing HDC activity.

Diagnosis and treatment of thoracic outlet syndrome

Patients who develop symptoms of thoracic outlet syndrome (TOS) have a predisposing anatomic abnormality. In most patients with TOS, the symptoms are caused by entrapment of the brachial plexus and they do not arise from compression of the subclavian artery, as was previously thought. The tests advocated for diagnosing this common syndrome (i.e., evaluating the positional compression of the artery when the arms are raised, the neck is turned, or the shoulders are braced) cannot accurately diagnose this syndrome. There are two reasons for this. The symptoms of TOS are not related to the compression of the artery in the outlet in 98% of patients, and 75% of normal individuals without symptoms show diminished radial pulse on various provocation tests. We employed four timed provocation tests (minute tests) to diagnose TOS: the timed Morley test, timed Wright test, timed Eden test, and elevated arm stress exercise, all of which are very sensitive. In normal individuals without symptoms, 20% experience transitional symptoms such as slight pain and tiredness, on these tests indicating a subclinical state. TOS is treated by keeping the thoracic outlet wide, this being done either conservatively or surgically. In 1993 and 1994, we conservatively treated 418 of 422 patients with TOS by means of active exercise, a brace, and by block therapy. These measures did not reduce the symptoms in 23 of these patients, so surgical treatment was indicated. In the remaining 4 of the 422 patients, conservative treatment was not indicated and surgery was performed directly. All the patients showed significant clinical improvement of varying degree.OBJECTIVE Thoracic outlet syndrome (TOS) is clinically common, but liable to be misdiagnosed. We would like to emphasize the recognition of TOS, and through thorough examination for a complete relief from indicated operation. METHODS 13 cases receiving surgical operations in PUMC hospital from 1982 to 1996 are reported and discussed the cause of misdiagnosis, investigate the various kinds of abnormalities and compare the result of operation. RESULTS 92% of the patients had experence of being misdiagnosed for other diseases, the history may be as long as 10 years. In the operations we found 8 kinds of anatomic abnormalities that cause the symptoms and complete relief is satisfactory. CONCLUSIONS We have to emphasize the recognition of TOS. The thorough physical examination is important to diagnosis. Patients with typical and apparent symptoms need an operation to relieve the thoracic outlet through the transaxillary approach.