K A Behranwala1, N Nasiri, R A'Hern, G P H Gui. 1. Department of Pathology, Information Technology and Statistics, Royal Marsden NHS Trust, Fulham Road, London SW3 6JJ, UK.
Abstract
INTRODUCTION: Pure myoepithelial carcinoma of the breast is a rare tumour of controversial histogenesis. Little is known about its natural history and long-term outcome following treatment. METHODS: All patients with pure myoepithelial carcinoma treated at our institution between 1970 and 2001 were studied with respect to pathological features, outcome and prognosis. RESULTS: Six patients were identified. The median age was 60 (40-66) years and median follow-up was 34.5 months (range 14-76) months. Four tumours were T1 and one was T2 (one tumour size unknown). There were two moderately differentiated and three well-differentiated tumours (grade could not be assessed in one patient). Oestrogen and progesterone receptor could be assessed in five patients and all were negative. Primary treatment was wide local excision with clear radial margins. Lymph node assessment was negative in all patients. One patient received adjuvant radiotherapy. Three patients developed local recurrence at 15, 38 and 50 months and two patients developed distant metastasis at 30 and 79 months. The local recurrences were treated by further excision but two patients developed distant metastasis at intervals of 15 and 26 months, respectively. Two patients have died of the disease and four remain well. The 2-year and 5-year survival was 88% (SE, 6) and 55% (SE, 16), respectively. Large tumour size is a prognostic indicator of poor outcome. CONCLUSION: Pure myoepithelial carcinoma of the breast adopts an aggressive clinical course with an outcome comparable to poorly differentiated adenocarcinoma of the breast.
INTRODUCTION: Pure myoepithelial carcinoma of the breast is a rare tumour of controversial histogenesis. Little is known about its natural history and long-term outcome following treatment. METHODS: All patients with pure myoepithelial carcinoma treated at our institution between 1970 and 2001 were studied with respect to pathological features, outcome and prognosis. RESULTS: Six patients were identified. The median age was 60 (40-66) years and median follow-up was 34.5 months (range 14-76) months. Four tumours were T1 and one was T2 (one tumour size unknown). There were two moderately differentiated and three well-differentiated tumours (grade could not be assessed in one patient). Oestrogen and progesterone receptor could be assessed in five patients and all were negative. Primary treatment was wide local excision with clear radial margins. Lymph node assessment was negative in all patients. One patient received adjuvant radiotherapy. Three patients developed local recurrence at 15, 38 and 50 months and two patients developed distant metastasis at 30 and 79 months. The local recurrences were treated by further excision but two patients developed distant metastasis at intervals of 15 and 26 months, respectively. Two patients have died of the disease and four remain well. The 2-year and 5-year survival was 88% (SE, 6) and 55% (SE, 16), respectively. Large tumour size is a prognostic indicator of poor outcome. CONCLUSION: Pure myoepithelial carcinoma of the breast adopts an aggressive clinical course with an outcome comparable to poorly differentiated adenocarcinoma of the breast.