Mediastinal and retroperitoneal fibrosis as a manifestation of breast cancer metastasis: A case report and literature review

RATIONALE: Mediastinal and retroperitoneal fibrosis as a manifestation of metastasis from malignancies is rare disease and particularly, cases of mediastinal fibrosis have been rarely reported. PATIENT CONCERNS: A 60-year-old woman presented with dyspnea and bilateral flank pain. The patient had no previous history of malignancy. DIAGNOSES: A contrast-enhanced chest computed tomography scan revealed a left breast mass and infiltrative soft tissue masses in the mediastinum and retroperitoneum, which showed high fluorodeoxyglucose uptake on positron emission tomography scan. The left breast mass was proven as a malignancy on biopsy and surgical excisional biopsy of the mediastinal mass revealed metastasis from the breast cancer on histopathologic examination. INTERVENTIONS: Our patient was treated with palliative hormone therapy for the primary breast cancer and metastasis with mediastinal and retroperitoneal fibrosis. OUTCOMES: Follow-up imaging studies showed improvement of the primary breast cancer and also metastasis. LESSONS: We report this rare case to emphasize that mediastinal and retroperitoneal fibrosis can be a presentation of metastasis from various primary malignancies. We expect that appropriate diagnosis and treatment for metastatic mediastinal and retroperitoneal fibrosis can have a beneficial effect on disease course and prognosis of the patient.