Supplementary Material for: Invasive cystic hypersecretory ductal carcinoma of breast: Challenges in diagnosis and man-agement

Cystic hypersecretory lesions of the breast are a spectrum of conditions ranging from cystic hyper-secretory hyperplasia, CHH with atypia and invasive cystic hypersecretory carcinoma. It is a sub-type of ductal carcinoma of breast. The tumour is very infrequent and hence, not studied extensive-ly. This culminates in the fact that it does not feature as part of the WHO classification of breast tumours. However, a good knowledge about its distinct pathological features can avert misdiagnosis and help to differentiate CHC from other conditions. So far only 22 cases of invasive CHC have been reported, 3 of which were microinvasive. Only 7 cases of axillary lymph node metastasis have been documented. We report a case of invasive cystic hypersecretory carcinoma of the breast that was metastatic to the axilla and refractory to neoadjuvant chemotherapy. Our case report aims to add to the limited store of information available on the disease, so that large scale studies can be conducted in the future in order to elaborate on its clinical and biological characteristics.