168. EMANGIOPERICYTOMA: CLINICAL EXPERIENCE WITH A LITTLE KNOWN TUMOUR ENTITY

Abstract

Purpose of the study: We present our cases of hemangiopericytomas treated surgically in our department of orthopaedic oncology. The purpose of this work was to study this vascular tumour rarely reported in the orthopaedic surgery in order to establish epidemiological, management, and prognostic elements.

Material and methods: This was a retrospective descriptive study of patients seen since 1995 with benign (n=4) or malignant (n=16) hemangiopericytoma. The large majority were FNCLCC grade 2. Mean follow-up was ten years. Course before diagnosis was longer for benign tumours (14 years) than malignant tumours (0.9 years). Tumour localization was the lower limb (55%), the upper limb (3%) (constantly involving the scapular girdle) and isolated tumours (sternum, dorsal tumours). Two patients presented metastasis at diagnosis. A biopsy was obtained in all cases.

Results: The sample contained soft haemorrhagic tissue in all cases. The typical histology was a proliferating vascular architecture with either a fibrous or muscular component. Immunohistochemistry studies revealed positive labelling for vimentin and CD99. The diagnosis of malignancy was particularly difficult, often because of the poor knowledge of pericyte differentiation. For the benign tumour, treatment consisted in resection followed by clinical and radiographic surveillance every six months. No recurrence was observed at more than five years follow-up. For the malignant tumours, all patients were given neoadjuvant chemotherapy followed by wide resection. Adjuvant chemotherapy, determined according to the resection margins and presence of not of metastasis, was instituted for 60% of patients and associated with radiotherapy for two. The total-remission survival for malignant tumours was 60% at five years. Local recurrence was noted in 18% of patients and development of metastasis in 10%. Mortality was 20%.

Discussion: The histology diagnosis was not straightforward, particularly for confirming the benign nature of the tumour; search for specific markers is needed for routine diagnosis.

Conclusion: The results obtained in this series provide valuable information for the diagnosis of sarcoma, particularly concerning the controversial issue of the aggressiveness of malignant tumours.