Comparison between preoperative biopsy and post-excision histology results in sarcoma: experience at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa.

Background: Tumour size, grade and subtype are the main prognostic factors in adult patients presenting with soft-tissue sarcoma. Planning for appropriate management, including the need for additional staging investigations and neoadjuvant therapy, is dependent on reliable preoperative histopathological results.

Objectives: To determine whether there is agreement between preoperative and post-excision histological findings in patients presenting with soft-tissue sarcoma, and whether the agreement is influenced by the subtypes of sarcomas.

Patients And Methods: Records of adult patients who had soft-tissue sarcomas excised were reviewed. Kaposi's sarcoma and gastrointestinal stromal tumours were excluded. Data were retrieved from the Department of Anatomical Pathology of the National Health Laboratory Service and theatre records at Chris Hani Baragwanath Academic Hospital, and included patient demography, tumour sites and size, HIV status, biopsy types and post-excision histological findings.

Results: Records of 153 patients were found (median age 44 years). The majority of the sarcomas were >5 cm in diameter, deep seated and localised in extremities. The commonest subtype, irrespective of HIV status, was dermatofibrosarcoma protuberans. Fine-needle aspiration biopsy (FNAB) results were inaccurate in determining the malignant nature, grade and subtype of sarcoma. Rates of accurate tumour subtype classification following core needle and incision biopsies when compared with post-excision histological findings were 73.1% and 78.3%, respectively.

Conclusion: FNAB should not be used in the primary evaluation of soft-tissue tumours. A report of spindle cells on the FNAB smear should be followed by core needle or incision biopsy. Incision biopsy is superior to core needle biopsy in the classification of sarcomas by subtype.