title: Bizarre parosteal osteochondromatous proliferation (Nora's lesion) of the foot.
abstract: A 22-year-old man presented with a growing lump on the fifth metatarsal of the right foot. Radiographically, the lesion was a calcified mass stuck on to the bone. The T2-weighted magnetic resonance images showed heterogeneity in intensity. A tumor was suspected and an excisional biopsy was done. The lesion was composed of a cartilaginous cap and bone tissue. Histological examination revealed characteristic features of bizarre parosteal osteochondromatous proliferation (BPOP), such as hypercellularity, a blue tinctorial quality in the osteocartilaginous interfaces, and a scattering of binucleated or bizarre enlarged chondrocytes. Immunohistochemically, basic fibroblast growth factor was expressed in nearly all chondrocytes within the cartilaginous cap, while vascular endothelial growth factor was expressed only in enlarged chondrocytes near the osteocartilaginous interfaces. Reverse transcription-polymerase chain reaction detected chondromodulin-I transcripts in the tissue of the cartilaginous cap. These findings indicate that the processes occurring in BPOP are similar to those occurring in endochondral ossification in the growth plate, and they support the concept that BPOP is a reparative process. BPOP is a rare tumorous lesion of the bone and is occasionally confused with other benign or malignant conditions. Thus, it is important to consider the clinical, radiographical and the gross histological features of the lesion when making a diagnosis.
authors.affiliation: Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki, Japan. horiguchi@ipu.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Horiguchi
authors.forename: M
authors.initials: M
authors.lastname: Sakane
authors.forename: M
authors.initials: M
authors.lastname: Matsui
authors.forename: Y
authors.initials: Y
authors.lastname: Wadano
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D001859:Bone Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D004273:DNA, Neoplasm / Q000032:analysis; D016228:Endothelial Growth Factors / Q000032:analysis; D016222:Fibroblast Growth Factor 2 / Q000032:analysis; D006133:Growth Substances / Q000032:analysis / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins; D008682:Metatarsal Bones / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D015831:Osteochondroma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D011859:Radiography; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D016228:Endothelial Growth Factors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D008565:Membrane Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2; C068675:CNMD protein, human