Seem every one agree this is a signet ring cell ca, breast primary (one type of lobular ca) or metastatic ca. Generally it is a primary tumor. But we can do IHC, CK7, ck20, ER, CDX2 pr to rule out GI primary.

Often

Breast: ck7+/ck20-, ER+, CDx2-

GI: CK7-/ck20+, er-, CDx2+

In fact GI: gastric + colonic origin

E-cadherin seems not very useful (see below article).  No lot study for p120.

abin译：似乎所有人都同意印戒细胞癌，乳腺原发（小叶癌的一个亚型）或转移癌。它一般是原发肿瘤。可以做CK7, ck20, ER, CDX2 pr 排除消化道转移（胃和结肠）。

乳腺：ck7+/ck20-, ER+, CDX2-

消化道：CK7-/ck20+, ER-, CDX2+

E-cadherin似乎没有太大帮助（见以下论文）。p120研究不多。