title: Atypical and malignant granular cell tumors in Japan: a Japanese Musculoskeletal Oncology Group (JMOG) study.
abstract: BACKGROUND
  Malignant granular cell tumors (MGCTs) are extremely rare neoplasms with only a limited number of studies published to date. The aim of this study is to elucidate the clinicopathological characteristics and prognostic factors of MGCTs.
  
  
  METHODS
  This is a multi-institutional retrospective study of MGCTs with a central pathological review. A total of 18 cases were retrieved. Specimens were blindly reviewed by two pathologists based on the diagnostic criteria by Fanburg-Smith et al. Kaplan-Meier survival probabilities were calculated, and risk factors for poor prognosis were evaluated.
  
  
  RESULTS
  Three and fifteen cases were diagnosed as atypical GCTs (AGCTs) and mGCTs according to the Fanburg-Smith et al. classification, respectively. Four (one atypical and three malignant) cases had metastasis at the first presentation, including lymph node metastasis. Three out of ten cases treated with wide resection developed local recurrence. Although prolonged static disease periods of ≥1 year were observed in four cases receiving chemotherapy, all cases with local recurrence or metastasis, including two atypical cases, eventually died of disease. The 5- and 10-year overall survival rates for localized MGCTs were 69.2 and 34.6 %, respectively. The presence of necrosis was revealed as a risk factor associated with adverse clinical outcomes.
  
  
  CONCLUSIONS
  MGCTs have high rates of recurrence and metastasis including lymph node metastasis. As histologically atypical cases also have metastatic potential, close attention should be paid to AGCTs. The combination of histological evaluation and tumor size may lead to more accurate diagnosis of this rare neoplasm.
authors.affiliation: Department of Orthopaedic Oncology and Surgery, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan. jungo@saitama-med.ac.jp.
authors.forename: Jungo
authors.initials: J
authors.lastname: Imanishi
authors.affiliation: Department of Orthopaedic Oncology and Surgery, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yazawa
authors.affiliation: Department of Human Pathology, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
authors.affiliation: Diagnostic Pathology Center, Hakujikai Memorial Hospital, 5-11-1 Shikahama, Adachi-ku, Tokyo, 123-0864, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Department of Orthopaedic Surgery, Niigata University Medical and Dental Hospital, 754, Ichibancho, Asahimachidori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Department of Orthopaedic Surgery, Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ae
authors.affiliation: Department of Orthopedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Matsumine
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Torigoe
authors.affiliation: Department of Orthopaedic Surgery, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, Nagoya, Nagoya, 464-8681, Japan.|Department of Physical Therapy, Nagoya University School of Health Sciences, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Sugiura
authors.affiliation: Department of Orthopaedic Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka, Osaka, 537-8511, Japan.|Department of Orthopaedic Surgery, Kawachi General Hospital, 1-31 Yokomakura, Higashiosaka, Osaka, 578-0954, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Joyama
mesh_terms: D000328:Adult; D005260:Female; D016586:Granular Cell Tumor / Q000401:mortality / Q000473:pathology*; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies
keywords: Atypical granular cell tumor; Chemotherapy; Malignant granular cell tumor; Pathological review; Radiotherapy; Surgery