# Occult lobular breast carcinoma presenting as bilateral ovarian masses: A case report

## TL;DR

A rare case of hidden breast cancer presenting as ovarian masses is reported, highlighting the importance of accurate diagnosis through histopathology and immunohistochemistry.

## Contribution

This case report highlights a rare presentation of occult lobular breast carcinoma as bilateral ovarian metastases, emphasizing diagnostic challenges and the role of immunohistochemistry.

## Key findings

- Occult lobular breast carcinoma can present as bilateral ovarian masses, mimicking primary ovarian cancer.
- Immunohistochemistry with GATA-3, GCDFP-15, and ER/PR helps confirm breast origin in ovarian metastases.
- Ovarian metastases from occult breast cancer are rare and often misdiagnosed without comprehensive evaluation.

## Abstract

Occult breast cancer (OBC) is a challenging condition that most commonly presents with axillary lymphadenopathy. Distant metastases are rare, and ovarian involvement is one of the most frequently misdiagnosed conditions. This report aims to highlight a rare presentation of OBC manifesting as bilateral ovarian metastases.

A 55-year-old woman with a history of ulcerative colitis presented with new-onset urinary stress incontinence. During the initial workup, there was an incidental finding of bilateral ovarian masses with malignant features. Elevated ovarian tumor markers initially suggested epithelial ovarian cancer. The patient underwent laparoscopic investigation, and multiple biopsies were obtained. Histopathological examination of the ovarian masses demonstrated features characteristic of invasive lobular carcinoma of breast origin, confirmed by immunohistochemical staining positive for CKAE1/AE3, GATA-3 and GCDFP-15 and negative for markers of primary ovarian and gastrointestinal tumors. The bilateral ovarian involvement and distinct tumor cell cytomorphology suggested a metastatic origin. The patient underwent breast MRI which showed no detectable evidence of a primary breast tumor. The final diagnosis was occult lobular breast carcinoma presenting with bilateral ovarian metastases.

Ovarian metastases originating from OBC are rare and present a diagnostic challenge due to the absence of a detectable primary tumor. A multidisciplinary approach incorporating histopathological evaluation and targeted immunohistochemistry is essential for accurate diagnosis and appropriate management.

Although rare, OBC can present as bilateral ovarian masses. Enhanced awareness and a comprehensive diagnostic approach are critical for improving patient outcomes.

•Occult lobular breast carcinoma may present as bilateral ovarian masses, mimicking primary ovarian cancer.•Elevated ovarian markers and absent breast lesions can mislead diagnosis toward primary gynecologic cancer.•IHC with GATA-3, GCDFP-15, and ER/PR confirms breast origin in ovarian metastases.

Occult lobular breast carcinoma may present as bilateral ovarian masses, mimicking primary ovarian cancer.

Elevated ovarian markers and absent breast lesions can mislead diagnosis toward primary gynecologic cancer.

IHC with GATA-3, GCDFP-15, and ER/PR confirms breast origin in ovarian metastases.