Biomedical subjects

Akio Sakamoto

Publications and source records attributed to Akio Sakamoto.

26 records · Page 2Linked to original sources

PubMed2002

Solitary fibrous tumor in the retroperitoneal space: report of a case.

Solitary fibrous tumors (SFTs) are spindle-cell neoplasms originally described in the pleura. It is now known that these tumors can develop in many sites. This report describes the case of a well-circumscribed tumor located around the superior mesenteric artery (SMA), which was initially thought to be either a superior SMA aneurysm, a lymphoma, or a neurogenic tumor. Histological examination demonstrated the tumor to be composed of a cellular proliferation of ovoid to spindle cells with a fine collagenous matrix in the short fascicles. Immunohistochemical staining was strongly positive for CD34 and negative for factor VIII, cytokeratin, desmin, and muscle-specific actin (HHF-35). These findings suggested a diagnosis of SFT in the retroperitoneal space. To our knowledge, this is the first report of an SFT located around the SMA. Based on the above findings, it is important to include SFT in the differential diagnosis of retroperitoneal tumors located around the SMA.

Carcinoma↗

PubMed2002

Vascular compression caused by solitary osteochondroma: useful diagnostic methods of magnetic resonance angiography and Doppler ultrasonography.

Osteochondroma is a common benign bone tumor that sometimes causes vascular complications when the lesion is situated near the knee. Venous complications are seen less frequently. We report two cases of solitary osteochondroma that arose in the distal femur. The patients were an 11-year-old boy and a 16-year-old boy, both of whom were suffering from bone protuberance and lower leg swelling due to congestion. In both patients, magnetic resonance imaging (MRI) revealed dilated popliteal veins at a site distal from the tumors or superficial veins. MR angiography (MRA) showed compressed popliteal arteries, and Doppler ultrasonography revealed weaker blood flow in the dorsalis pedis arteries in the lower leg with the tumor than in the other lower leg. The former patient complained of pain due to swelling in the lower leg, and for this reason the patient underwent resection of the tumor. After resection, both the swelling and the pain were decreased, and Doppler ultrasonography also revealed normal blood flow in the artery. The latter patient had swelling, but no pain, in the lower leg, and accordingly this patient has been followed carefully without resection, since there is always the possibility of irreversible vascular damage caused by osteochondroma, such as arterial or venous occlusion. We present two patients with osteochondroma, both of whom suffered from swelling of the lower leg due to venous compression by the tumor. In both cases, MRI and MRA were useful to show the presence of vascular compression. Doppler ultrasonography could also reveal the blood flow disturbance objectively, even in current osteochondroma cases in which there were no arterial symptoms.

Adolescent↗

PubMed2002

High-dose chemotherapy and autologous peripheral blood stem-cell transfusion after conventional chemotherapy for patients with high-risk Ewing's tumors.

Although the overall results of treatment of Ewing's tumors have improved, patients with high-risk factors, including metastatic disease at diagnosis, bulky primary tumors, axial sites, and age >15 years, continue to have poor prognoses. The effects of high-dose chemotherapy and autologous peripheral blood stem-cell transplantation on high-risk Ewing's tumor patients have been reported. In most of these studies, conditioning and high-dose regimens varied among patients. Here we report the feasibility and effects of a high-dose chemotherapy regimen conducted in our institution. Seven patients with high-risk Ewing's tumors were treated by high-dose chemotherapy. The patients received four cycles of remission induction chemotherapy, and then peripheral blood stem cells were mobilized by high-dose etoposide and harvested. Myeloablative chemotherapy consisted of carboplatin, ifosfamide, and etoposide. The patients have 5-year overall and relapse-free survival probabilities of 0.86 and 0.81, respectively. The results were significantly better than those for patients treated with conventional chemotherapy alone. None of the patients had severe side effects. The high-dose regimen and transplantation were feasible and well tolerated. The poor prognoses of high-risk Ewing's tumor patients may be improved by high-dose chemotherapy with peripheral blood stem cell transplantation. However, the real impact of the therapy on the clinical outcome of patients with high-risk Ewing's tumors should be evaluated in a prospective, randomized study.

Adolescent↗

PubMed2002

Solitary lymphangioma of the femur. A case report.

Lymphangioma of the bone is a benign lesion, characterized by newly formed lymph vessels. It usually occurs in a diffuse manner or as multiple lesions. Solitary lymphangioma of the bone is an extremely rare condition. We herein describe a case of solitary lymphangioma of the femur in a 55-year-old woman who presented with knee pain. Radiographs showed an eccentric osteolytic lesion in the distal femur. This is the first reported case of solitary lymphangioma of the bone occurring in the femur.

Biopsy, Needle↗

PubMed2002

Mutation analysis of human cytokeratin 8 gene in malignant rhabdoid tumor: a possible association with intracytoplasmic inclusion body formation.

The rhabdoid cell, which is typically observed in malignant rhabdoid tumor (MRT) and other malignant neoplasms, has an eosinophilic cytoplasm containing a spheroid perinuclear inclusion body. This distinct cell is known to act as a highly aggressive indicator in many types of malignant tumors and is characterized by aggregates of intermediate filaments, comprising both vimentin and cytokeratin (CK) 8, which is mainly expressed in simple-type epithelium such as liver and intestine. To clarify the cause of the inclusion body formation, we analyzed the alteration of the complete human CK8 gene (KRT 8: 1724 base pairs) in seven samples of MRT (three from frozen materials and four from cultured cell lines) by reverse-transcriptase polymerase chain reaction, followed by direct sequencing. In addition, the two cell lines, Huh7 and HeLa, which lacked rhabdoid feature, six pediatric malignant tumors, including three cases of primitive neuroectodermal tumor (PNET) and three of Wilms' tumor; and 15 normal liver tissue (as a control) were also analyzed. All MRT samples had missense mutations in the human KRT 8 gene, i.e., Arg89 --> Cys (5/7); Arg --> Cys251 (3/7); Glu267 --> Lys (6/7); Ser290 --> Ile, Met; (7/7) and Arg301 --> His(4/7), none of which was detected in any control samples. Among these mutations, the most noteworthy findings were that Arg89 belongs to the H1 subdomain of the head domain and that Arg251 belongs to the short nonhelical linker segment, or L1-2. Both these mutations are noted for their relationships to lateral protofilament-protofilament interactions. In addition, Ser290 has been previously reported to be a phosphorylation site, which has been recognized to play an important role in filament organization, leading to conformational change of the CK8 filaments. In conclusion, mutated codons of CK8 gene in MRT were located in the important region involved in the conformational change of intermediate filament.

Amino Acid Sequence↗

PubMed2002

Molecular analysis of p53, MDM2, and H-ras genes in osteosarcoma and malignant fibrous histiocytoma of bone in patients older than 40 years.

Some investigators have reported that the histological features of osteosarcoma (OS) arising in elderly patients are different from those in younger patients; however, a molecular biologic study of OS in elderly patients has not been documented. In this study, 23 cases of OS (15 osteoblastic and 8 MFH-like types) and 18 cases of MFH of bone in patients 40 years of age or older were analyzed for mutation of the p53 gene, amplification of the MDM2 gene, and mutation of the H-ras gene, using formalin-fixed paraffin-embedded materials. We also examined the expression of p53, MDM2, and p21WAF1 protein immunohistochemically and assessed the proliferative activities using the monoclonal antibody MIB-1. p53 immunoreactivity was recognized in 5 of 23 OS cases (22%), whereas p53 gene mutations were also detected in 5 of 23 OS cases (22%; osteoblastic [4/15; 27%] and MFH-like [1/8; 18%] types) and in 4 of 18 cases of MFH of bone (22%). There was a statistically significant correlation between p53 immunoreactivity and p53 mutation status in OS (P =.0482). All those cases of osteoblastic OS and MFH of bone that had p53 mutations, with the exception of one case of MFH of bone that had a silent mutation, showed aggressive biologic behavior (dead of disease within 12 mo), in contrast to the MFH-like OS cases (alive without disease at 22 mo). Three cases of OS (13%) and three cases of MFH of bone (17%) showed immunoreactivity for MDM2. As for gene alteration, three cases of OS (13%) and 3 cases of MFH of bone (17%) demonstrated MDM2 amplification. MDM2 amplification showed a significant correlation with the expression of MDM2 protein in OS (P =.0344). p21WAF1 expression was detected in three cases of OS (13%) and in six cases of MFH of bone (33%). MDM2 alteration and p21WAF1 expression were not observed in any of the cases of MFH-like OS. MIB-1-LI showed a statistically significant correlation with p53 immunoreactivity and MDM2 immunoreactivity in OS (P =.0307 and P =.0358, respectively). H-ras mutation at Codons 12 and 13 was not recognized in any of the cases of OS or MFH of bone. In conclusion, although treatment differences during the time of study make it difficult to compare survival analysis, in the current study, p53 mutation in osteoblastic OS and MFH of bone in elderly patients seemed to be closely associated with the progression of the tumor, which was not the case in MFH-like OS. Furthermore, MDM2 alteration and p21WAF1 expression were demonstrated only in osteoblastic OS and MFH of bone, whereas they were not recognized in MFH-like OS. Although the number of patients in this analysis was small, it would appear that MFH-like OS may have some characteristic biologic aspects when compared with osteoblastic OS and MFH of bone in elderly patients.

Adult↗

PubMed2002

Beta-catenin accumulation and gene mutation in exon 3 in dedifferentiated liposarcoma and malignant fibrous histiocytoma.

CONTEXT: beta-Catenin is an adhesion molecule that also plays a role in the Wnt signaling pathway. Objective.-To analyze beta-catenin mutation and accumulation in a series of liposarcomas and malignant fibrous histiocytomas. DESIGN: beta-Catenin mutation in exon 3 was studied using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing analysis in 30 formalin-fixed, paraffin-embedded liposarcomas. The tumors included 12 dedifferentiated liposarcomas, characterized by both high-grade anaplastic components and well-differentiated liposarcoma components, plus 18 well-differentiated liposarcomas (10 lipoma-like and 8 sclerosing-type cases). The 2 components of dedifferentiated liposarcomas were analyzed independently. beta-Catenin accumulation in the nuclei or cytoplasm and Ki-67 expression (cell-proliferation marker, MIB-1 labeling index) were examined immunohistochemically. Nine storiform-pleomorphic-type malignant fibrous histiocytomas were also studied. RESULTS: Dedifferentiated liposarcomas showed mutation in 2 cases (17%) and accumulation in 5 cases (42%). One of the 2 cases that showed mutations had a mutation in the well-differentiated component; this mutation was silent. The other case had mutations that differed between the 2 components. In well-differentiated liposarcomas, mutation was not seen in any of the cases (0/18; 0%); however, accumulation was seen frequently in the sclerosing-type cases (5/8; 63%), but not in the lipoma-like cases (0/10; 0%). Malignant fibrous histiocytomas showed mutation and accumulation in 5 (56%) and 4 (44%) cases, respectively, without any exact correlation between the cases. Cases with accumulation had a higher MIB-1 labeling index than those without, among both the sclerosing-type well-differentiated liposarcomas (P <.05) and the malignant fibrous histiocytomas. CONCLUSIONS: Our results suggest the possible involvement of beta-catenin activation caused by beta-catenin mutation in liposarcoma and malignant fibrous histiocytoma, but the contribution would seem to be different, depending on the tumor type. beta-Catenin accumulation is also thought to be related to cell proliferation in some of the cases.

Adult↗

PubMedDate not supplied

Prognostic factors in the so-called malignant mesenchymoma: a clinicopathological and immunohistochemical analysis.

The term "malignant mesenchymoma" (MM) has traditionally been applied to a group of malignant soft tissue tumors that are characterized by the presence of two or more different mesenchymal tissue components in the same neoplasm. Currently, sarcomas with multilineage differentiation fulfilling the criteria of MM tend to be diagnosed as specific sarcomas with heterologous differentiation (e.g., de-differentiated liposarcoma) rather than MM; however, some cases of these tumors are difficult to classify. The purpose of this study was to analyze the clinicopathological and immunohistochemical features of these unclassifiable tumors, the so-called MM, and to determine whether some parameters are a useful adjunct for the classification of these tumors from the viewpoint of clinical outcome. Twelve cases of so-called MM were investigated retrospectively. The patients (six male, six female) ranged in age from 6 to 71 years (mean 48 years). Tumor size ranged from 3 to 20 cm (mean 13 cm). Tumor locations included the retroperitoneum (five cases), abdominal wall (two), thigh (two), forearm (one), lung (one), and parotid gland (one). The differentiated mesenchymal components were rhabdomyosarcomatous (RMS) (six cases), liposarcomatous (five), chondrosarcomatous (five), osteosarcomatous (five), or leiomyosarcomatous (four). Follow-up in all cases (range 4-129 months; mean 36 months) showed a 67% local recurrence rate, a 33% metastatic rate, and a 50% disease-related mortality. The patients who were under 40 years of age or who had an RMS component showed significantly worse survival than did patients in the other groups. The other mesenchymal components showed no significant correlation with survival. The immunophenotypes of p53 and mdm2 were almost identical between the two mesenchymal components in each case; however, there was no significant correlation between either of these immunophenotypes and the clinical outcome. None of the other factors (gender, tumor site, tumor size, or MIB-1-labeling index) was found to be a statistically significant prognostic indicator. In conclusion, a patient age under 40 years and the presence of an RMS component appear to be poor prognostic indicators of survival in patients with so-called MM, and to be a useful adjunct for the classification of these tumors.

Adolescent↗