# Hypermetabolic Pulmonary and Mediastinal Lesions With Elevated Cancer Antigen (CA) 15-3 and CA 27-29 in a Patient With a History of Ovarian and Breast Cancer

## TL;DR

A patient with a history of breast and ovarian cancer showed signs of metastasis, but was diagnosed with sarcoidosis, highlighting the need for careful diagnosis and treatment.

## Contribution

This case highlights the diagnostic challenge of distinguishing sarcoidosis from cancer recurrence using imaging and tumor markers.

## Key findings

- The patient's symptoms and imaging suggested metastatic cancer, but biopsy revealed sarcoidosis.
- A therapeutic trial of steroids led to clinical improvement and reduced tumor marker levels.
- Early PET response can help differentiate sarcoidosis from malignancy in complex cases.

## Abstract

Breast cancer affects around 13% of women. Breast cancer gene 1 (BRCA1) carriers are prone to lung and lymph node metastasis, while breast cancer gene 2 (BRCA2) carriers tend to have bone metastasis. Findings of pulmonary nodules, mediastinal lymphadenopathy, and elevated markers such as cancer antigen (CA) 15-3 and CA 27-29 suggest metastatic disease. Here, we present the case of a patient with BRCA1-positive breast cancer in remission and a history of ovarian cancer with mediastinal lymphadenopathy and pulmonary nodules, with avid fluorodeoxyglucose uptake on positron emission tomography (PET) scan and elevated CA 15-3 and CA 27-29.

A 70-year-old female with a history of bilateral breast and ovarian cancer and a positive BRCA test presented with pulmonary nodules, mediastinal lymphadenopathy, and elevated CA 15-3 and CA 27-29. Imaging showed mediastinal and hilar lymphadenopathy. A PET scan revealed increased metabolic activity in the lymph nodes and pulmonary lesions. Fiberoptic bronchoscopy and endobronchial ultrasound lymph node sampling demonstrated granulomatous inflammation without malignant cells. The patient underwent a therapeutic trial of steroids with clinical improvement of symptoms and decreased hypermetabolic activity in chest lesions, as well as a decrease in tumor markers.

The coexistence of sarcoidosis and breast cancer is rare; sarcoidosis can coexist, precede, or appear after breast cancer. In both conditions, tumor markers and PET avidity are seen, which makes diagnosis and management challenging. In case of ambiguity, biopsy is crucial. This case underscores the importance of integrating clinical, pathological, and imaging data to reach an accurate diagnosis and consider a therapeutic trial of steroids. Furthermore, the early PET response to treatment can be pivotal in differentiating between sarcoidosis and malignancy, especially in complex clinical scenarios. Proper differentiation is paramount to avoid therapeutic missteps and ensure appropriate patient management.