Is Invasive Mucinous Breast Carcinoma A Rare Variant With Neuroendocrine Differentiation?

Abstract

We want to bring your attention towards the rare variant of
breast cancer hence promoting its early detection and
screening. The main advantage of early diagnosis is reduced
tumor size without distant dissemination at the initial
treatment.
Neuroendocrine malignancies are heterogenous with neuronal
and endocrinal properties. Neuroendocrine cells are present
throughout the body and hence neuroendocrine tumors
(NETS) can arise from any anatomic region. Although breast
cancer is the most frequently diagnosed cancer in women,
breast NETS are very rare. With a prevalence of 1-2 cases
per 10,000 women, breast NETS make up only 0.1% of all
breast cancers and less than 1% of all NETS1. In other
histopathological subtypes of breast carcinomas, invasive
ductal carcinoma is the most common breast tumor reported
worldwide of which mucinous (colloid) variant is the rare
histological subtype, accounts for 1-7% of all invasive
carcinomas 2. However, 30% of invasive breast tumor are
seen with nneuroendocrine differentiation, and is most
commonly associated with mucinous and solid papillary
carcinomas and therefore treated similar to another invasive
carcinoma of breast3.
Mucinous carcinoma is well circumcised and have soft
gelatinous consistency. It has two subtypes, pure mucinous
or mixed type. Pure mucinous carcinoma is a rare cancer
which most commonly occur in older women and less than
1% occurs in younger than 35 years of age4. Pure type is
composed of entirely mucinous carcinoma with two further
subtypes, hypocellular and hypercellular variants. Axillary
lymph node involvement is commonly rare. In a study of
Kashiwagi, demographical data of 71 patients with mucinous
carcinoma of the breast have suggests tumor size ranged
from 0.5cm-12.3cm with mean tumor diameter-3.1cm6.
Mucinous carcinoma with neuroendocrine differentiation
shows good prognosis but tumors which are expressed of
HER 2 neu shows negative prognosis and has increased risk
of recurrence and metastasis. Primary neuroendocrine tumors
of breast have worst prognosis due to lack of long-term
survival data hence it's difficult to make a prognosis for this
carcinoma5