Connecting the Dots - A Pulmonary Mystery

A 36-year-old woman with a history of endometriosis and prior ovarian cystectomy presented with dyspnea and respiratory failure.

Initial chest radiography and CT demonstrate innumerable, randomly distributed pulmonary nodules. Further evaluation with an 18F-FDG PET/CT scan revealed substantial FDG uptake in the pulmonary nodules and low FDG uptake in three lesions in the uterus and an ovary. These findings led to leading differential diagnoses of hematogenous pulmonary metastases or miliary tuberculosis. A CT-guided lung biopsy was performed for a definitive diagnosis, and histopathological analysis revealed benign leiomyomatous tissue, confirming Pulmonary Benign Metastasizing Leiomyoma (PBML). The patient was started on tamoxifen therapy, which resulted in clinical improvement.

PBML is a rare condition characterized by the hematogenous dissemination of histologically benign smooth muscle tissue from a uterine leiomyoma, often following surgical manipulation. It can be a diagnostic challenge, as its presentation can mimic widespread infection or metastatic disease.