Mucinous cystic neoplasm (MCN) with an associated invasive carcinoma
Mucinous cystadenocarcinoma and columnar cell mucinous carcinoma of the breast are rare invasive carcinomas characterized by large columnar cells with bland, basal nuclei and abundant intracytoplasmic mucin. The tumours are cystic and vary in size from 0.8 to 19 cm.
The two variants are distinguished according to the appearance of the intracytoplasmic mucin: tumours with cystic mucin are classified as mucinous cystadenocarcinoma, those with solid mucin as columnar cell mucinous carcinoma.
The cystic variant is histologically characterized by numerous cysts, focal atypia, loss of polarity, eosinophilic cellular transformation and invasion of the surrounding stroma.
The columnar cell variant consists of compact to loose aggregations of round and convoluted glands lined by a single layer of columnar mucinous epithelium.
The very few reported cases of mucinous cystadenocarcinoma and columnar cell mucinous carcinoma occurred in women 49 to 67 years of age
Koenig C, Tavassoli FA (1998)
. Recurrence or metastasis has not been observed
Mucinous cystadenocarcinoma of the breast.
Am J Surg Pathol 22: 698-703
Tavassoli FA, Devilee P (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Breast and Female Genital Organs.
IARC Press: Lyon 2003