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Biomedical subjects

Tetsuji Yamamoto

Publications and source records attributed to Tetsuji Yamamoto.

At least 55 records · Page 3Linked to original sources
PubMed2003

Luxatio erecta (inferior dislocation of the shoulder): a report of 5 cases and a review of the literature.

Luxatio erecta (inferior dislocation of the glenohumeral joint) is an unusual type of shoulder dislocation. The authors present 5 new cases of luxatio erecta. All cases were hyperabduction injuries. In all cases, closed reduction was accomplished by a traction-countertraction maneuver. Three of the 5 subjects sustained concomitant fractures of the greater tuberosity. One underwent open reduction and internal fixation of the greater tuberosity. One suffered axillary nerve injuries. No vascular injuries were noted in our series. The mechanism of the injury is discussed.

Accidental Falls↗
PubMed2002

Aspiration biopsy of nodular sarcoidosis of the muscle.

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis.

Biopsy, Needle↗
PubMed2002

Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma.

Extraskeletal osteosarcoma is a rare malignant soft tissue tumor whose cytologic findings are infrequently reported. We describe scrape and fine-needle aspiration biopsy (FNAB) cytology findings of an extraskeletal osteosarcoma in the right shoulder of a 24-yr-old man. Initial computed tomography revealed multiple ossification foci within the lesion. After excision of the primary tumor, the tumor recurred 13 months later. Scrape smears of both the primary tumor and FNAB smears of the recurrent tumor revealed moderate cellularity, cell clusters, and individual cells, closely associated with dense, homogeneous, acellular matrix material. The cells had elongated, oval, or partially bizarre-shaped nuclei with a coarse chromatin pattern and prominent nucleoli. The scrape smears contained large fragments of matrix material consistent with osteoid.

Adult↗
PubMed2002

Reliability of fine-needle aspiration biopsy in the initial diagnosis of soft-tissue lesions.

We retrospectively reviewed fine-needle aspiration biopsy (FNAB) specimens of 301 soft tissue lesions of the extremities and trunk. Final diagnoses were 137 benign and 86 malignant neoplasms and 78 nonneoplastic lesions. Of the 301 FNAB samples, 279 (93%) were adequate for cytologic diagnosis. The adequate FNAB specimens were initially grouped into three broad categories: benign (197 cases), malignant (57 cases), and suspicious for malignancy (25 cases). Sensitivity and specificity for diagnosis of a malignant lesion were 92% and 97%, respectively. The specimens were cytomorphologically classified into nine categories: small round (14 cases), spindle cell (77 cases), epithelioid/polygonal (16 cases), pleomorphic (29 cases), myxoid (19 cases), lipomatous (37 cases), epithelial (23 cases), inflammatory lesions (28 cases), and others (36 cases). Specific FNAB diagnoses were correct in 151 of 279 cases (54%) in combination with clinical and radiologic findings. FNAB is a valuable technique for the primary diagnosis of soft-tissue lesions.

Adolescent↗
PubMed2002

Neural fibrolipoma of the superficial peroneal nerve in the ankle: a case report with immunohistochemical analysis.

This report presents a case of neural fibrolipoma arising from the superficial peroneal nerve in the ankle. A 28-year-old woman was referred with a soft tissue mass in the anterior aspect of the right ankle, which had been gradually enlarging for the past 10 years. Magnetic resonance imaging showed a mass lesion, measuring approximately 8 x 3 x 2 cm, with high to partially low signal intensity on both T1- and T2-weighted images. A band of low signal intensity within the lesion, which is indicative of coexistence with the tumor and the superficial peroneal nerve, could be detected on both T1- and T2-weighted images. The patient underwent an excisional biopsy. The specimen microscopically consisted of nerve bundles and fibro-fatty proliferation with abundant collagen fibers. Immunoreactivity for CD34 antigen antibody was detected in fibrous spindle cells. This is the first report to present an immunohistochemical profile of neural fibrolipoma. Neural fibrolipoma should be considered as a differential diagnosis when a lipomatous lesion is encountered in the foot or ankle as well as in the upper extremities.

Adult↗
PubMed2002

Osteosarcoma of the distal radius treated by intraoperative extracorporeal irradiation.

Osteoblastic osteosarcoma in the distal radius of a 50-year-old woman was treated by en bloc resection, intraoperative extracorporeal irradiation, and reimplantation. Twenty-three months after surgery finger function was good. No tumor recurrence or distant metastasis was found at the final follow-up examination. Intraoperative extracorporeal irradiation and reimplantation is an easy and convenient reconstructive surgical procedure after en bloc excision of a tumor in the distal radius. A biologic reconstruction with a precise anatomic fit is possible, and long-term endoprosthetic problems and maintenance of bone-banking facilities for allografts are avoided.

Bone Neoplasms↗
PubMed2002

Maximizing flexion after total knee arthroplasty: the need and the pitfalls.

Currently available knee prostheses can provide 100 degrees to 110 degrees of knee flexion, which is usually good enough for most daily activities, such as ascending or descending stairs and rising from chairs. Many activities require deep knee flexion, however. In Asian countries, deep knee flexion also is needed for special cultural activities. Preoperative range of motion, surgical technique, prosthesis design, and postoperative rehabilitation are important factors that influence postoperative range of motion.

Arthroplasty, Replacement, Knee↗
PubMed2002

Intracortical lipoma of the femur.

The authors report on a rare case of intracortical lipoma of the right femur in a 74-year-old woman. Magnetic resonance imaging and computed tomography of the femur demonstrated an intracortical lesion in the lateral diaphysis. No medullary involvement by the lesion was noted. Both imaging methods revealed the presence of fat in the lesion. Histologically, the tumor consisted of a large area of mature adipose tissues, admixed with foci of fat necrosis, calcification, and myxoid degeneration. Total excision of the tumor was curative. This is the second reported case of intracortical lipoma.

Aged↗
PubMed2002

Repeat tears of repaired menisci after arthroscopic confirmation of healing.

We undertook 114 arthroscopic meniscal repairs in 111 patients and subsequently carried out second-look arthroscopy to confirm meniscal healing at a mean of 13 months after repair. Stable healing at the repaired site was seen in 90. Of these, however, 13 had another arthroscopy later for a further tear. The mean period between the repair and the observation of a repeat tear was 48 months. Of the 13 patients, 11 had returned to high activity levels (International Knee Documentation Committee level I or II) after the repair. An attempt should be made to preserve meniscal function by repairing tears, but even after arthroscopic confirmation of stable healing repaired menisci may tear again. The long-term rate of healing may not be as high as is currently reported. Second-look arthroscopy cannot predict late meniscal failure and may not be justified as a method of assessment for meniscal healing. Young patients engaged in arduous sporting activities should be reviewed regularly even after arthroscopic confirmation of healing.

Adolescent↗
PubMed2002

Epithelioid leiomyosarcoma of the external deep soft tissue.

Epithelioid leiomyosarcoma in the external deep soft tissue is extremely rare. Most epithelioid leiomyosarcomas occur in the uterus. We present a case of epithelioid leiomyosarcoma occurring in the muscle of the thigh of a 78-year-old man. Histologically, the tumor predominantly consisted of round or polygonal cells arranged in sheets with a focal spindle cell component. Immunohistochemical analysis revealed that the tumor cells expressed vimentin, alpha-smooth muscle actin, and alpha-sarcomeric actin. The tumor was negative for desmin, S100 protein, glial fibrillary acidic protein, pan-keratin, epithelial membrane antigen, CAM 5.2, HMB-45, leukocyte common antigen, factor VIII-associated antigen, and CD34. Electron microscopically, some tumor cells contained abundant actin-type filaments in their cytoplasm.

Actin Cytoskeleton↗
PubMed2002

Biphasic synovial sarcoma in a 13-month-old girl.

Synovial sarcoma is a malignant mesenchymal neoplasm which commonly occurs in the extremities of adults. We report on a 13-month-old girl with synovial sarcoma in the lateral aspect of her right ankle. The tumor was treated with total excision and 50Gy of irradiation. Histopathologic examination of the excised tumor revealed a biphasic synovial sarcoma. There was no evidence of local recurrence or distant metastasis of the tumor at follow-up examination 24 months postoperatively.

Ankle↗
PubMedDate not supplied

Magnetic resonance delineation of the anterior cruciate ligament of the knee: flexed knee position within a surface coil.

The purpose of this study was to evaluate the effect of the knee position at three different flexion angles in magnetic resonance (MR) delineation of the anterior cruciate ligament (ACL) in the knee and to determine the optimal knee position. Thirteen knees of normal volunteers were examined at 15 degrees, 30 degrees, and 45 degrees of flexion with a surface coil, and three sets of obtained oblique sagittal MR images were evaluated by four observers. MR images at 30 degrees of knee flexion most clearly delineate compared with those at 15 degrees and 45 degrees of knee flexion. We recommended examining the knee in 30 degrees of flexion.

Adult↗
PubMedDate not supplied

Fibroma of tendon sheath originating from the knee joint capsule.

We present a rare case of fibroma of the tendon sheath originating from the posterior joint capsule of the knee in a 50-year-old man. Magnetic resonance (MR) imaging revealed a lesion posterior to the medial femoral condyle. The lesion showed hypointensity on all T1-weighted, T2-weighted, short tau inversion recovery (STIR), and contrast-enhanced T1-weighted images. Plain computed tomographic (CT) scans showed a lesion with isodensity to muscle. The lesion showed no enhancement on postcontrast CT scans.

Fibroma↗
PubMedDate not supplied

Subacute osteomyelitis of long bones: diagnostic usefulness of the "penumbra sign" on MRI.

Although subacute osteomyelitis of long bones is not uncommon, it is usually confined to metaphysis. Two unusual cases of subacute osteomyelitis that traversed a growth plate are described. There may be some radiological difficulties in distinguishing it from other malignant or benign lesions. On magnetic resonance (MR) imaging, both of the present cases showed characteristic four-layered appearance and the penumbra sign. These characteristic findings on MR imaging are considered to facilitate establishing the radiologic diagnosis.

Adolescent↗