Recurrent anomalies of 6q25 in chondromyxoid fibroma

Chondromyxoid fibroma is a rare benign bone tumor most commonly arising in the metaphysis of long bones in young adults. Histopathologically, chondromyxoid fibroma may be difficult to distinguish from other cartilaginous neoplasms. Recently, a pericentric inversion of chromosome 6 [inv(6)(p25q13)] has been proposed as a specific genetic marker for chondromyxoid fibroma. In this study, cytogenetic and spectral karyotypic analyses of 2 chondromyxoid fibroma cases showed clonal abnormalities of chromosome 6 but at a breakpoint on the long arm (q25) distal to that described in the pericentric inversion. These findings suggest that several distinct breakpoints on chromosome 6 are nonrandomly involved in chondromyxoid fibroma.

Cytogenetic findings in 73 osteosarcoma specimens and a review of the literature

Tumor-specific chromosomal abnormalities have been identified in several histologic subtypes of sarcomas. Characterization of recurrent chromosomal abnormalities has provided direction for molecular investigations of pathogenetically important genes. Cytogenetic reports of osteosarcoma, the most common primary malignant bone tumor, are relatively rare. In this study, 73 osteosarcoma specimens from 51 patients were cytogenetically analyzed following short-term culture. Clonal chromosomal abnormalities were detected in 47 and included one haploid specimen, 18 near-diploid specimens, 17 near-triploid, 8 near-tetraploid, 1 near-hexaploid, and 2 specimens with multiple clones of different ploidy levels. Examination of the present data and previously published data (111 clonally abnormal osteosarcoma specimens) reveals that chromosomal bands or regions 1p11-13, 1q10-12, 1q21-22, 11p15, 12p13, 17p12-13, 19q13, and 22q11-13 are most frequently rearranged and the most common numerical abnormalities are +1, -9, -10, -13, and -17. Partial or complete loss of the long arm of chromosome 6 also was seen in all cases of the present study and all previously published cases describing structural abnormalities of 6q. Parosteal osteosarcoma, a prognostically favorable osteosarcoma subtype, was characterized by the presence of a ring chromosome accompanied by no or few other abnormalities. Complex karyotypes were seen nearly exclusively in the high-grade lesions. These findings indicate that specific chromosomal bands and/or regions are nonrandomly involved in osteosarcoma and may provide useful clinical information.

Chondroblastoma: classic and confusing appearance at MR imaging

PURPOSE

To define the characteristics of chondroblastoma at magnetic resonance (MR) imaging and the combination of findings that are diagnostic for chondroblastoma.

MATERIALS AND METHODS

From January 1987 through December 1992, 22 patients with histologically confirmed chondroblastoma and prior MR imaging examinations were seen. Patients included 16 men and six women, aged 10-58 years (median, 17 years). Retrospective analysis of findings at MR imaging, plain radiography, computed tomography, and bone scanning was performed.

RESULTS

Low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins were well defined with high-resolution T2-weighted (repetition time > or = 1,500 msec, echo time > or = 70 msec) MR imaging. Adjacent bone-marrow and soft-tissue edema and periosteal reactions were more dramatically demonstrated on MR images than on radiographs. Bone marrow edema was prominent in all but five cases. Obvious periosteal reaction and adjacent soft-tissue edema were visible in 17 cases.

CONCLUSION

Knowledge of the MR imaging findings of chondroblastoma will allow accurate diagnosis and help avoid confusion with infection and aggressive neoplasms.

Audiologic threshold monitoring of patients receiving ototoxic drugs. Preliminary report

An effort was made to determine the efficacy of auditory threshold monitoring of patients receiving ototoxic drugs. Forty-four patients treated with either tobramycin or vancomycin for osteomyelitis were tested at the beginning of treatment, following treatment, and twice weekly during treatment when possible. All patients had renal function carefully monitored. Peak and trough drug levels were kept out of the toxic range throughout the study. In no patient did indisputable ototoxicity occur, and therefore, no conclusion about the most efficacious schedule for auditory monitoring of patients receiving ototoxic drugs was made, and what constitutes a significant intratherapeutic threshold shift is still in question. Until further data are collected, monitoring of renal function and peak and trough drug levels, as well as patient counseling, is recommended. Pretherapy and posttherapy auditory monitoring and intratherapeutic monitoring of high-risk patients and those who develop aural symptoms may prove beneficial.

The effect of inadvertent tumor contamination of wounds during the surgical resection of musculoskeletal neoplasms

The effect of inadvertent tumor violation with visually evident wound contamination during the surgical resection of musculoskeletal neoplasms is unknown. In an attempt to assess the significance of wound contamination by tumor tissue, the incidence of local recurrence in 28 cases of known wound contamination was determined. The influence of immediate lavage, re-excision, subsequent surgical margin, and the use of adjuvant chemotherapy and/or radiation therapy upon local recurrence was assessed. Achieving a wide surgical margin by immediate re-excision after contamination gave a significantly lower incidence of recurrence than those with lesser final margins (P less than 0.01). The use of postoperative adjuvant chemotherapy or irradiation resulted in a lower recurrence rate, but the difference between those with and without adjuvant treatment had statistically less significance than the surgical margin on the incidence of local recurrence (P less than 0.2). The risk of local recurrence after contamination was not influenced by the histologic grade of the tumor.

Scoliosis secondary to osteoblastoma of the rib

An 8-year-old girl with a progressive, painless spinal deformity is presented. She was found to have an atypical scoliosis secondary to a stage 3 benign osteoblastoma of the rib. This case is presented to emphasize that atypical scoliosis in skeletally immature individuals requires a thorough investigation for an underlying cause.