Large cell, epithelioid, telangiectatic osteoblastoma: a unique pseudosarcomatous variant of osteoblastoma.

A previously undescribed large-cell, epithelioid, and aneurysmal variant of osteoblastoma with minimal osteoid-production--simulating telangiectatic osteosarcoma, epithelioid angiosarcoma, and metastatic carcinoma is reported. The tumor occurred in the mandible of a 14-year-old girl. The light microscopic, immunohistochemical, ultrastructural, cell proliferation, and DNA-ploidy studies, as well as the 7-year disease-free follow-up period all indicate a benign osteoblastic tumor.

del(6)(q12q15) as the sole cytogenetic anomaly in a case of solitary infantile myofibromatosis.

We describe a case of light microscopically typical solitary, infantile myofibromatosis in a 6-month old boy. The myofibroblastic differentiation of the tumor was supported by immunohistochemical and ultrastructural analyses. Cytogenetic and FISH analyses revealed a pseudodiploid karyotype with an interstitial deletion of the long arm of one chromosome 6, del(6)(q12q15), as the sole anomaly.

Malignant and benign tumors in patients with neurofibromatosis type 1 in a defined Swedish population.

Background: The development of malignant and benign tumors in patient with neurofibromatosis type 1 (NF1) was investigated in a long term follow-up study of 70 adult NF1 patients living in Göteborg, Sweden, on January 1, 1978. Their mean age at that time was 44 years (range, 20-81 years). The 70 NF1 patients had previously been investigated in a population-based study.

Life expectancy, mortality and prognostic factors in neurofibromatosis type 1. A twelve-year follow-up of an epidemiological study in Göteborg, Sweden.

Neurofibromatosis type 1 (NF1) is a genetic disease with an extremely wide range of manifestations. As yet, the individual course of NF1 cannot be predicted, and it is uncertain to what extent the disorder is associated with increased mortality. In order to gain insights into these aspects, we have conducted a 12-year follow-up study of 70 adult NF1 patients in the city of Göteborg, Sweden, whereby life expectancy, mortality, causes of death and the prognostic value of clinical findings were investigated.

Pseudomalignant spindle cell proliferations of the urinary bladder.

Twelve cases of polypoid, nonrecurrent, pseudomalignant spindle cell proliferations of the urinary bladder (eight women and four men) were analyzed. Two patients had a simultaneous urinary bladder carcinoma. The lesions were characterized by proliferating spindle- or strap-shaped cells, which on electron microscopic examination (performed in all 12 cases) revealed characteristics of fibroblasts and myofibroblasts.