Cowden syndrome is known as multiple hamartoma syndrome because a variety of benign, proliferative lesions are seen in various organs. The common conditions are benign proliferative lesions in the breast, thyroid, uterine, and skin nodules. This syndrome is associated with susceptibility to breast cancer, and is reported as the most common malignancy involving women with Cowden syndrome. In addition, bilateral breast cancers are reported in 25% of patients, so annual screening magnetic resonance imaging (MRI) is recommended (
1,
2,
5,
8-
13).
So far, there has been no reported cases of pure cribriform carcinoma in Cowden syndrome patients and the histologic subtype of breast cancer in has been rarely reported.
In a study conducted by Schrager et al. (
2), among 14 patients of breast cancer, only one patient had ductal carcinoma in situ (DCIS) and 11 patients had both DCIS and invasive carcinoma. Among the 11 patients, only one patient had infiltrating tubular carcinoma and lobular carcinoma in situ (LCIS). The most common type of infiltrating carcinoma was ductal as well (86%). All the patients hand mixed histologic subtypes of DCIS (assorted combination of cribriform, micropapillary, papillary, or solid).
There was a case report of synchronous bilateral breast carcinoma in Cowden syndrome. The tumor from the right breast consisted of DCIS of intermediate grade that was predominantly cribriform type. Different from the tumor in the right breast, the tumor in the left breast revealed DCIS of high-grade with various types, such as papillary, cribriform, solid, and comedo-type (
14).
In our case, invasive ductal carcinoma was observed in the left breast showing a highly suspicious sonographic feature. On the other hand, a low suspicious mass with pathologic proven pure cribriform carcinoma was detected in her right breast.
Page et al. (
9) described infiltrating cribriform carcinoma of the breast, which is characterized by a predominant cribriform growth pattern of its invasive component, is a distinct histological type of invasive carcinoma. This is a rare condition of breast cancer, with an incidence of 0.3% to 3.5%. Pure infiltrating cribriform carcinoma is defined as being almost entirely (> 90%) of an invasive cribriform pattern. The radiologic findings of infiltrating cribriform carcinoma are not well known since few studies have described the disease. The tumor was mammographically occult in 22% - 50% of the patients (
8-
10). Therefore, sometimes the tumor is not definitely detected on mammography.
Especially the tumor occult sometimes on mammography (
10). Sonographic assessment findings were classified as Breast Imaging Reporting and Data System (BI-RADS) category 4A or 4C. The carcinoma has a low frequency of axillary nodal metastases and a favorable prognosis (
8,
11). In this case, mammography also did not reveal the mass, and the sonographic assessment findings were BI-RADS category 4A.
In conclusion, we have reviewed a case of Cowden syndrome in a woman diagnosed as invasive carcinoma of NST and contralateral cribriform carcinoma in the breast. There have been many reports of bilateral breast cancer with ductal cancer in patients with Cowden syndrome, and we report bilateral breast cancer with an exceptional pathology. Breast fibroadenomas, skin hemangiomas, gastric polyps, seborrheic hyperplasia, and benign thyroid lesions were also present in the patient.