FBJ virus was injected i.p. into 145 neonatal NIH Swiss [N:NIH(s)] mice. Eighty mice developed a total of 110 neoplasms by 5 months of age. The mean latent period of the tumors was 71 days (26 to 145) postinjection. The frequency of occurrence of neoplasms at different sites was: diaphragm, 45%; ribs, 14%; vertebrae, 14%; femora, 9%; pelvic bones, 5%; tibiae, 4%; sternebrae, 3%; and inguinal ar...

An 83-year-old woman presented with weakness in her right-hand and wrist extensors and swelling in the proximal part of the right forearm. Electromyography (EMG) confirmed involvement of posterior interosseous nerve at the level of proximal forearm. MR imaging demonstrated the characteristics of lipoma which extended on the anterolateral aspect of the right forearm and at the level of the radiu...

The differential diagnosis for an intra-articular lesion in the knee of a pediatric patient is broad. Diagnostic considerations include pigmented villonodular synovitis (PVNS)-the most common intra-articular tumor-and a variety of both benign and malignant tumors, including lipomas, hemangiopericytomas, nodular fasciitis, parosteal osteosarcomas, and fibromyxoid sarcomas. If there is concern ov...

A 50-year-old female presented with more than 20-year history of a large subcutaneous mass in the left parieto-occipital portion. Magnetic resonance (MR) imaging revealed the lipomatous mass to show a high signal intensity in both T1- and T2-weighted images. A part of the lipomatous lesion progressed into the underlying hyperostosis and skull. The preoperative diagnosis was skull invasion of a ...

The authors present five cases of periosteal osteosarcoma located in the femur (4) and tibia (1) in children and young adults (1 female and 4 males) with an age range of 9 - 23 years (mean age 15 years). Radiographs in all cases showed a broad-based soft tissue mass attached to the cortex with periosteal reaction and in two of them cortical disruption with extensive medullary involvement. Follo...