Unilateral breast enlargement as a presenting feature of small cell carcinoma of the lung.

Breast enlargement associated with carcinoma of the lung is most commonly a paraneoplastic manifestation of non-small cell carcinoma. Hormonally mediated proliferation of the glandular component of the breast leads to unilateral or bilateral enlargement. This report describes a patient with small cell carcinoma of the lung who presented with unilateral breast enlargement related to superior vena cava obstruction.