Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Hirokazu Chuman is active.

Publication


Featured researches published by Hirokazu Chuman.


Skeletal Radiology | 1995

The role of MR imaging in the diagnosis of alveolar soft part sarcoma-a report of 10 cases

Yukihide Iwamoto; Norio Morimoto; Hirokazu Chuman; Norio Shinohara; Yoichi Sugioka

ObjectiveThe objective of this study was to analyze the characteristics of alveolar soft part sarcoma using magnetic resonance imaging (MRI).DesignMRI studies of pathologically proven alveolar soft part sarcomas (ASPS) in ten patients were reviewed and compared with computed tomographic (CT) studies and angiograms.PatientsTen patients presented with a soft tissue mass of the extremities, neck, axilla, or buttocks. MR images were obtained in all patients prior to surgical intervention, chemotherapy, or irradiation.Results and ConclusionAlthough most soft tissue sarcomas are isointense relative to muscle on MRI T1-weighted images (T1WI), nine of the ten alveolar ASPS in the present study demonstrated high signal intensity on both T2 and T1WI. Flow voids were observed both at the core and at the margins of the tumors studied. Recognition of these characteristic MRI findings may lead to the early diagnosis of ASPS, especially when the clinical presentation is that of a slow-growing soft tissue mass in a young adult patient.


Virchows Archiv | 2004

Differential diagnosis of gastrointestinal stromal tumor and other spindle cell tumors in the gastrointestinal tract based on immunohistochemical analysis

Umio Yamaguchi; Tadashi Hasegawa; Taizo Masuda; Shigeki Sekine; Akira Kawai; Hirokazu Chuman; Tadakazu Shimoda

To confirm the usefulness of an immunohistochemical panel of antibodies for KIT (c-kit/CD117), CD34, desmin, smooth-muscle actin (SMA), h-caldesmon (HCD), S-100 protein, neuron-specific enolase (NSE), and beta-catenin, 297 mesenchymal and peripheral nerve-sheath tumors of the gastrointestinal tract and intra-abdominal locations including 211 gastrointestinal stromal tumors (GISTs), 12 leiomyomas, 18 leiomyosarcomas, 17 solitary fibrous tumors (SFTs), 14 schwannomas, and 25 desmoid-type fibromatoses (DTFs) were analyzed immunohistochemically. Consistent (100%) immunoreactivity for KIT, CD34, desmin and S-100, and nuclear accumulation of beta-catenin were detected in GISTs, SFTs, smooth-muscle tumors, schwannomas, and DTFs, respectively. Immunoreactivity for SMA, HCD, and NSE was observed in a wide range of these tumors. In addition, 418 bone and soft tissue tumors were enrolled in this study for KIT immunostaining. As a result, a limited number of these tumors were KIT positive, including synovial sarcoma that showed morphological similarity to GISTs. These findings suggest that KIT, CD34, desmin, S-100, and beta-catenin are key markers for clinical diagnosis of GISTs and other spindle cell tumors that may involve the gastrointestinal tract, whereas SMA, HCD, and NSE have only limited value.


Cancer | 2005

Expression of epidermal growth factor receptor, ERBB2 and KIT in adult soft tissue sarcomas : A clinicopathologic study of 281 cases

Osamu Sato; Takuro Wada; Akira Kawai; Umio Yamaguchi; Atsushi Makimoto M.D.; Yasuo Kokai; Toshihiko Yamashita; Hirokazu Chuman; Yasuo Beppu; Yoichi Tani; Tadashi Hasegawa

Little is known about the expression of receptor tyrosine kinases in adult soft tissue sarcomas (STS). In the current study, the authors analyzed the expression of epidermal growth factor receptor (EGFR), ERBB2, and KIT in 281 patients with STS who were treated in a single institution. Verification of the presence of an association with prognosis was performed.


Spine | 2003

Primitive neuroectodermal tumor and extraskeletal Ewing sarcoma arising primarily around the spinal column: report of four cases and a review of the literature.

Katsumi Harimaya; Yoshinao Oda; Shuichi Matsuda; Kazuhiro Tanaka; Hirokazu Chuman; Yukihide Iwamoto

Study Design. Report of four cases and a review of the literature. Objectives. To study the clinical features and prognosis of primitive neuroectodermal tumor or extraskeletal Ewing sarcoma arising around the spinal column. Summary of Background Data. Primitive neuroectodermal tumor or extraskeletal Ewing sarcoma that originates around the spinal column is very rare, and its prognosis is very poor. Methods. Four patients were diagnosed and underwent treatment. Results. Although all the patients received high-dose chemotherapy with or without radiotherapy after surgery, three patients died of the disease. Only one patient who received en bloc resection of the tumor combined with multiagent chemotherapy followed by high-dose chemotherapy with peripheral blood stem cell transplantation remains alive and continues to be disease free. Conclusion. The prognosis of the patients with primitive neuroectodermal tumor or extraskeletal Ewing sarcoma around the spinal column is very poor. Multiagent chemotherapy combined with en bloc resection and radiation therapy is the preferred treatment for patients with primitive neuroectodermal tumor or extraskeletal Ewing sarcoma around the spinal column.


Modern Pathology | 2000

Prognostic Significance of Apoptosis in Synovial Sarcoma: Correlation with Clinicopathologic Parameters, Cell Proliferative Activity, and Expression of Apoptosis-Related Proteins

Shigeto Kawauchi; Toshiro Fukuda; Yoshinao Oda; Tsuyoshi Saito; Atsunori Oga; Morishige Takeshita; Koichiro Yokoyama; Hirokazu Chuman; Yukihide Iwamoto; Masazumi Tsuneyoshi

bcl-2 overexpression in synovial sarcomas has been recently reported. Although it is widely known that bcl-2 suppresses apoptosis in various cells, there are no studies that have examined the significance of apoptosis in synovial sarcoma. In the present study, we visualized apoptotic tumor cells by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) method in 49 cases of primary synovial sarcoma. The degree of apoptosis was analyzed in relation to several clinicopathologic parameters, cell proliferative activity, and immunohistochemical expression of apoptosis-related proteins, including bcl-2, bax, bcl-x, bak, p53, p21 (WAF1/CIP1), Fas, and Fas ligand. TUNEL index (TUNEL-I) significantly correlated with the mitotic index (MI) (ñ = 0.60, P < .0001) and Ki-67 labeling index (MIB1-I) (ñ = 0.52, P = 0.0005). There was a highly significant association between high TUNEL-I value (>.8%) and poor prognosis (log-rank test; P < .0001). Many synovial sarcomas were diffusely positive for bcl-2 family proteins (bcl-2, bax, bcl-x, and bak) and were negative or only sporadically positive for Fas, Fas ligand, p53, and p21 (WAF1/CIP1) proteins. The results indicated that increased rate of apoptosis in primary synovial sarcoma was considered to be an indicator of poor prognosis. In addition, apoptosis in synovial sarcoma may be controlled by multiple apoptosis-regulating mechanisms, including the bcl-2 family.


Plastic and Reconstructive Surgery | 2005

Pelvic ring reconstruction with the double- barreled vascularized fibular free flap

Minoru Sakuraba; Yoshihiro Kimata; Hideo Iida; Yasuo Beppu; Hirokazu Chuman; Akira Kawai

Background: Although hemipelvectomy has been the standard treatment for malignant tumors of the pelvis, limb salvage surgery is now the treatment of choice, even for patients with advanced tumors. For these patients, pelvic reconstruction is needed to maintain the stability of the pelvis and the spinal column and to allow ambulation. In this report, the authors’ experiences with pelvic ring reconstruction are described. Methods: Pelvic ring reconstruction with free double-barreled vascularized fibular grafts was performed after resection of malignant pelvic tumors in five patients. The graft was fixed with a fixation plate and screws in three patients and with the Cotrel-Dubousset rod system in two patients. After surgery, perioperative and postoperative findings were evaluated. Results: In one patient, a pedicled rectus abdominis musculocutaneous flap was transferred to repair defects of the skin and underlying soft tissue. The free fibular graft was transferred successfully in four of five patients; however, the graft was removed in one patient because of infection with methicillin-resistant Staphylococcus aureus. After surgery, three of the four patients with successful grafts could walk with full weight bearing and without a cane; the fourth patient died as a result of multiple metastases to the lung before walking was attempted. Conclusions: The double-barreled fibular graft is well vascularized and can achieve satisfactory bone union. It is a safe and effective method for reconstructing the pelvic ring. Furthermore, the Cotrel-Dubousset rod system can provide rigid fixation soon after surgery and is useful for early rehabilitation of walking.


Sarcoma | 2012

Alveolar Soft Part Sarcoma: A Single-Center 26-Patient Case Series and Review of the Literature

Koichi Ogura; Yasuo Beppu; Hirokazu Chuman; Akihiko Yoshida; Noboru Yamamoto; Minako Sumi; Hirotaka Kawano; Akira Kawai

Background. Alveolar soft part sarcoma (ASPS) is a rare tumor, and little information is available regarding its clinical features and appropriate treatments. Methods. A retrospective review of 26 consecutive ASPS patients (12 male, 14 female; mean age of 27 years) treated at our institution over 30 years (mean followup; 71 months) was performed. Results. The primary tumor developed in the lower extremity (12), trunk (8), and upper extremity (6), with an average size of 7.2 cm (range, 2–14 cm). The AJCC stage at presentation was IIA (7), III (3), and IV (16). Surgical excision was performed in 20 patients (R0 18, R1 plus radiotherapy 2) without local recurrence. Six patients (stage IIA 3/7, stage III 3/3) later developed metastases after an average period of 28.7 months. The median survival of the 26 patients was 90 months, with overall 5/10-year survival rates of 64%/48%. AJCC stage and tumor size were significant prognostic factors. Significant palliation and slowing of metastasis progression were achieved with gamma knife radiotherapy. Nine patients receiving chemotherapy showed no objective response. Conclusions. ASPS is indolent but has a high propensity for metastasis. Early diagnosis and complete excision of the small primary tumor are essential in the treatment of ASPS.


Human Pathology | 1996

Proliferative activities in conventional chordoma: A Clinicopathologic, DNA flow cytometric, and immunohistochemical analysis of 17 specimens with special reference to anaplastic chordoma showing a diffuse proliferation and nuclear atypia

Takahiko Naka; Toshiro Fukuda; Hirokazu Chuman; Yukihide Iwamoto; Yoichi Sugioka; Masashi Fukui; Masazumi Tsuneyoshi

Chordoma shows various degrees of atypia histologically, however, the relationship between the histological features and the biological behavior still remains controversial. The authors subclassified 17 specimens with chordoma into two groups (ie, trabecular type showing a trabecular patterns and solid type mainly consisting of a diffuse proliferation of tumor cells). The histological grading was performed according to the degree of nuclear atypia on a scale of 1 to 3. Using DNA flow cytometric and immunohistochemical techniques, both the proliferative index (% S + G2 + M phase) and the MIB-1 labeling index (LI) of the tumor cells were estimated regarding their proliferative activities. In addition, p53 overexpression was also investigated using immunohistochemical techniques. There were eight (47.1%) specimens of trabecular type and nine (52.9%) of solid type. In nine specimens of solid type, those with higher nuclear atypia (grade 2 or 3) were significantly more frequent (five specimens, 55.6%) than in trabecular type in which all of the eight specimens were grade 1 (P = 0.44). The proliferative index was significantly higher in grade 2 or 3 lesions than in grade 1 lesions (P = .014), and the MIB-1 LI tended to be higher in solid type than in trabecular (P = .088). p53 overexpression was detected in two specimens of solid type, and the MIB-1 LI in these two specimens was significantly higher (P = .037) than that in the specimens without p53 overexpression. It was considered that the preceding anaplastic histological features, including either diffuse proliferation or high grade nuclear atypia, together with p53 overexpression, were thus closely related to the proliferative activities in chordomas.


International Journal of Radiation Oncology Biology Physics | 2016

Carbon Ion Radiation Therapy for Unresectable Sacral Chordoma: An Analysis of 188 Cases

Reiko Imai; Tadashi Kamada; Nobuhito Araki; Satoshi Abe; Yukihide Iwamoto; Toshifumi Ozaki; Chihiro Kanehira; Mitsunori Kaya; Kazuhisa Takahashi; Hirokazu Chuman; Hirohiko Tsujii; Masazumi Tsuneyoshi; Yoshihiro Nishida; Hiroaki Hiraga; Toru Hiruma; Rikuo Machinami; Akihiko Matsumine; Seiichi Matsumoto; Hideo Morioka; Takehiko Yamaguchi; Tsukasa Yonemoto

PURPOSE To evaluate the results of carbon ion radiation therapy administered to 188 patients with unresectable primary sacral chordomas. PATIENTS AND METHODS One hundred eighty-eight patients were treated with carbon ion radiation therapy at a single institute between 1996 and 2013 and retrospectively analyzed. The median age was 66 years. The highest proximal invasion reached past S2 level in 137 patients. The median clinical target volume was 345 cm(3). One hundred six patients received 67.2 gray equivalents (GyE)/16 fractions (fr), 74 patients received 70.4 GyE/16 fr, 7 patients received 73.6 GyE/16 fr, and 1 patient received 64.0 GyE/16 fr. RESULTS The median follow-up period was 62 months (range, 6.8-147.5 months). Seventy percent of patients were followed for 5 years or until death. The 5-year local control, overall survival, and disease-free survival rates were 77.2%, 81.1%, and 50.3%, respectively. Forty-one patients had a local recurrence. Sex, tumor volume, level of proximal invasion, and irradiated dose were unrelated to local control. There was grade 3 toxicity of the peripheral nerves in 6 patients and grade 4 toxicity of the skin in 2 patients. Ambulation remained in 97% of patients. CONCLUSIONS Carbon ion radiation therapy was safe and effective for unresectable chordoma and provided good local control and survival while preserving ambulation.


Journal of Orthopaedic Science | 2008

Myxoinflammatory fibroblastic sarcoma

Eisuke Kobayashi; Akira Kawai; Makoto Endo; Yoshiyuki Suehara; Ken Takeda; Fumihiko Nakatani; Takayuki Asano; Minoru Sakuraba; Hirokazu Chuman; Kunihiko Seki; Yasuo Beppu

Acral myxoinfl ammatory fi broblastic sarcoma (MIFS) was fi rst described in 1998 as a new entity in three independent reports by pathologists, Meis-Kindblom and Kindblom, Michal, and Montgomery et al. It occurs primarily in adults, with a peak incidence in the fourth and fi fth decades of life, and presents as a painless fi rm mass of the distal extremities, predominantly the hands and feet. Recently, proximally located MIFS has also been reported, and some authors have suggested dropping the adjective “acral” from the name of the tumor because of its possibly misleading nature. Histologically, MIFS is a poorly circumscribed and typically multinodular tumor. The most striking feature is infl ammatory infi ltration associated with a prominent myxoid matrix in variable proportions and the presence of bizarre virocyte or Reed-Sternberg-like cells and multivacuolated cells simulating lipoblasts. Surgical excision with a wide margin is considered the treatment of choice, as the tumor shows a high rate of local recurrence. Meis-Kindblom and Kindblom reported a 67% local recurrence rate within a median follow-up period of 5 years. However, the tumor is frequently diffi cult to diagnose correctly at the time of initial presentation because of its apparently benign nature, being a slowgrowing, small and painless mass in the distal extremity. As a result, there is a tendency for the tumor to be treated inadequately by referring physicians. Surgeons need to be mindful of MIFS, its nature, and the appropriate treatment necessary for this unique tumor. Case reports

Collaboration


Dive into the Hirokazu Chuman's collaboration.

Top Co-Authors

Avatar

Akira Kawai

Memorial Sloan Kettering Cancer Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Umio Yamaguchi

Sapporo Medical University

View shared research outputs
Top Co-Authors

Avatar

Akihiko Yoshida

Takeda Pharmaceutical Company

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge