Diagnosis of high-grade osteosarcoma by radiology and cytology: a retrospective study of 52 cases

Cytological diagnosis of osteosarcoma with emphasis on diagnostic pitfalls

INTRODUCTION

Fine needle aspiration is a well-established technique for evaluating primary and secondary bony lesions. With use in selected cases, it achieves a diagnostic yield comparable to biopsies.

METHODS

Cases of osteosarcoma (OS) with available histological follow-up were retrieved over a 10-year period. Detailed morphological evaluation was done, with special emphasis on pitfalls in the diagnosis of OS on cytology and the various variants of OS.

RESULTS

Of the 41 cases with available follow-up histology, 56% were correctly diagnosed as OS on cytology. The most common false-negative cytological diagnosis of OS, in 17% cases, was giant cell tumour. The possible explanations for this included low cellularity, minimal atypia, absence of typical osteoid, misinterpretation of metachromatic osteoid material as fibro-collagenous material and non-availability of radiology at time of aspiration.

CONCLUSION

A triple-phase evaluation including clinical evaluation, appropriate radiological correlation and cytology/histopathology, is important to clinch an accurate diagnosis.

Incidence Trends in the Diagnosis of Giant Cell Tumor of Bone in Sweden Since 1958

BACKGROUND

The Swedish Cancer Registry (founded in 1958) constitutes a unique resource for epidemiological studies of giant cell tumor of bone with potential for use for population-based studies of incidence over time. The aim of this study was to provide what we believe is the first modern population-based assessment of the incidence trends of giant cell tumor, a unique osteoclastogenic lytic stromal tumor with both benign and malignant histological forms, and to compare the findings with data from the same registry on osteosarcoma, a tumor that may display similar histological characteristics.

METHODS

Cases were identified with use of codes for pathological bone tumor (International Classification of Diseases [ICD]-7 196). Specific morphological coding distinguishes benign (PAD 741) from malignant giant cell tumor (PAD 746) and osteosarcoma (PAD 766).

RESULTS

During the period of 1958 to 2011, 4625 bone tumors were reported, including 505 giant cell tumors (383 benign and 122 malignant) and 1152 osteosarcomas. From 1958 to 1982 the ratio of malignant to benign giant cell tumors was 1.3, whereas from 1983 to 2011 the ratio inverted to 0.09, suggesting a change in the reporting or diagnosis of malignant or benign cases. Cases of giant cell tumor diagnosed from 1983 to 2011 displayed an age and sex distribution (median age at diagnosis, 34.0 years; 54% female) that were consistent with those in large published case series but differed from those in 1958 to 1982 (median age at diagnosis, 31.5 years; 48% female). The most current data (1983 to 2011) showed the giant cell tumor incidence in Sweden to be 1.3 per million per year, while the osteosarcoma incidence was 2.3 per million per year.

CONCLUSIONS

Early Swedish Cancer Registry data (1958 to 1982) revealed a higher proportion of malignant giant cell tumors than seen in large sequential case series and a distinct age and sex profile compared with more recent data (1983 to 2011). This likely represents changes in the diagnostic workup and introduction of multidisciplinary review of giant-cell-containing tumors around 1982. Recent data may reflect the impact of expert centralized biopsy and multidisciplinary case review and more comprehensive reporting of benign giant cell tumors.

Imprint smear cytology of chondroblastic osteosarcoma: a case report

Imprint cytology is gaining increasing popularity in the diagnosis of musculoskeletal lesions and in many patients; a definitive diagnosis can be rendered from aspiration smears alone. However, evaluation of tissue architecture is a major limitation and therefore cytological diagnosis has to be confirmed on histopathology. The authors take this opportunity to report a case of chondroblastic osteosarcoma occurring in the middle 1/3rd of the left thigh in a 35 year old male, diagnosed on imprint cytology and confirmed on histopatholgy.