title: Primary alveolar soft part sarcoma of bone.
abstract: OBJECTIVE
  Alveolar soft part sarcoma is a distinct, rare soft tissue tumour occurring primarily within the skeletal muscles or musculofascial planes in young adults. Primary involvement of bone is extremely rare. We report on six patients with alveolar soft part sarcoma occurring primarily in bone.
  
  
  RESULTS
  Thorough clinical and radiographic examinations were done to rule out any other primary site. The patients were four women and two men aged 17-35 years (mean, 24.5 years). The primary site of the tumour was the femur in three patients, the ilium in one and the fibula in two. In one of the patients with fibular involvement, the tibia was also involved by direct extension. Of the long bone lesions, three were centred in the metaphysis and one in the diaphysis. Radiographically, all of the lesions demonstrated an osteolytic pattern of bone destruction with ill-defined margins and a wide zone of transition between the lesion and adjacent normal bone. Microscopically, all tumours showed the typical histological pattern of alveolar soft part sarcoma. Diastase-resistant, periodic acid-Schiff-positive crystalline structures were identified within the cytoplasm and confirmed ultrastructurally. Immunohistochemically, a keratin stain was negative in all cases; there was positive staining for MyoD1 in the cytoplasm but not the nuclei. Distant metastasis developed in four patients; one died.
  
  
  CONCLUSIONS
  Alveolar soft part sarcoma arising in bone is extraordinarily rare but should be considered in the differential diagnosis of metastatic hypernephroma in a young patient.
authors.affiliation: Department of Pathology, College of Medicine, Kyung Hee University, Seoul, South Korea.
authors.forename: Y K
authors.initials: YK
authors.lastname: Park
authors.forename: K K
authors.initials: KK
authors.lastname: Unni
authors.forename: Y W
authors.initials: YW
authors.lastname: Kim
authors.forename: C S
authors.initials: CS
authors.lastname: Han
authors.forename: M H
authors.initials: MH
authors.lastname: Yang
authors.forename: D E
authors.initials: DE
authors.lastname: Wenger
authors.forename: F H
authors.initials: FH
authors.lastname: Sim
authors.forename: D R
authors.initials: DR
authors.lastname: Lucas
authors.forename: J R
authors.initials: JR
authors.lastname: Ryan
authors.forename: Y A
authors.initials: YA
authors.lastname: Nadim
authors.forename: T
authors.initials: T
authors.lastname: Nojima
authors.forename: C D
authors.initials: CD
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001859:Bone Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D001932:Brain Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging / Q000556:secondary*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging / Q000556:secondary*; D008297:Male; D011859:Radiography; D018234:Sarcoma, Alveolar Soft Part / Q000737:chemistry / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor