Small Cell Carcinoma in the Mammary Gland: Primary or Metastatic? A Diagnostic Challenge

Metastatic tumours to the mammary gland are relatively uncommon as compared to primary breast malignancies. Such lesions can pose diagnostic dilemmas for both the clinician and the pathologist because it is often difficult to categorize the tumour as primary or secondary and to determine the site of origin. We present the case of a thirty year old female who was diagnosed with small cell neuro-endocrine carcinoma in the mammary gland, probably of pulmonary origin. The diagnostic challenges posed by such a case are highlighted.