Primary retroperitoneal spindle cell liposarcoma: pathological and immunohistochemical findings.
Spindle cell liposarcoma (SCLS) is presently regarded as a rare variant of well-differentiated liposarcoma (WDLPS), which has the potential for aggressive clinical behavior. WDLPS occurs most frequently in the limbs and retroperitoneum. The most common site of SCLS occurrence is the upper limbs or shoulder girdle. Herein we report the first case of primary retroperitoneal SCLS. A 60-year-old Japanese man presented with a right inferior abdominal mass. Complete excision of the mass displayed a yellowish spherical tumor with a well-circumscribed appearance measuring 98 x 95 mm. Pathological examination of the tumor revealed a neural-like spindle cell proliferation set in a fibrous background that was associated with an atypical lipomatous component, which usually included lipoblasts. Mitotic cells were scarce. Immunohistochemical analysis demonstrated that lipoblasts were S100 positive, spindle cells were CD34 positive, and both spindle cells and lipoblasts were MDM2 negative. The Ki-67 labeling index was <2%. At one year follow up, the patient was alive without local recurrence or metastasis. Although the proliferative activity of this tumor did not indicate strong malignancy, retroperitoneal liposarcoma generally has a poor prognosis. Accumulation of cases of SCLS is necessary to facilitate a more accurate evaluation of the pathology and clinical behavior of this tumor.
Shioi
Yoshihiro
Y
Division of Molecular Diagnostic Pathology, Department of Pathology, Iwate Medical University School of Medicine, Uchimaru, Morioka, Japan. y-shioi@mta.biglobe.ne.jp
Hasegawa
Tadashi
T
Otsuka
Koki
K
Fujisawa
Kentaro
K
Itabashi
Tetsuya
T
Kimura
Toshimoto
T
Wakabayashi
Go
G
Mue
Yoshiharu
Y
Uesugi
Noriyuki
N
Sugai
Tamotsu
T
D014408:Biomarkers, Tumor / Q000378:metabolism; D049109:Cell Proliferation; D018572:Disease-Free Survival; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008080:Liposarcoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012186:Retroperitoneal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012509:Sarcoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen