INTRODUCTION: The presence of multiple bilateral pulmonary nodules on chest imaging has an expansive differential diagnosis that includes metastatic disease, autoimmune disorders, and infectious etiologies. The differential tends to encompass less common etiologies in the setting of younger and asymptomatic patients. One such entity is benign metastasizing leiomyoma (BML).
CASE PRESENTATION: A 43 year old female presented to her primary care physician with complaints of nasal stuffiness, cough for approximately four weeks, and low back pain without associated fevers. Her medical history was notable for congenital deafness, cognitive delay, hepatitis of unclear etiology treated with low dose prednisone since childhood, and history of abdominal myomectomy followed by subsequent hysterectomy with unilateral oophorectomy, She was prescribed antibiotics for the cough, but due to lack of improvement presented to the Emergency Department two weeks later with worsening low back pain and continued non-productive cough. Initial imaging of the chest demonstrated innumerable bilateral pulmonary nodules without evidence of lymphadenopathy. Evaluation of the nodules included CT scan which confirmed the finding of multiple bilateral pulmonary nodules of varying sizes suggestive of metastases seen on the chest x-ray. Patient underwent CT scan of the abdomen and pelvis to examine for possible primary neoplastic lesions, of which none were found. A CT guided fine needle aspiration was subsequently performed which yielded only macrophages and clusters of benign bronchial cells. PET scan was also performed and demonstrated no hypermetabolic foci within the lungs. She was discharged from the hospital as symptoms had resolved and eventually underwent left lower lobe wedge resection approximately three and a half months following her initial presentation. Pathologic examination of the tissue demonstrated smooth muscle proliferation with entrapped epithelial clefts consistent with benign metastasizing leiomyoma. Pathology from the patient’s prior myomectomy and hysterectomy was reviewed and felt to be consistent with leiomyoma without evidence of leiomyosarcoma. Patient was started on leuprolide and received 3 doses with stabilization of nodules on subsequent chest x-rays. She remained asymptomatic during this period. Follow up chest x-ray 12 months following cessation of leuprolide demonstrated minimal enlargement of some of the nodules with repeat chest x-ray 6 months later demonstrating clear increase in size and number of lung lesions. At this time, the patient underwent salpingo-oophorectomy of her remaining ovary. Follow up chest imaging demonstrated significant improvement in the size of her nodules and she remains asymptomatic.
DISCUSSION: Benign metastasizing leiomyoma is an infrequent cause of asymptomatic pulmonary nodules which is generally seen in pre-menopausal females following myomectomy or hysterectomy for uterine fibroids. The lesions are most commonly seen in the lung as well demarcated nodules scattered throughout both lungs fields. These lesions are usually asymptomatic, but can occasionally present with chest discomfort or cough. The etiology of the lesions remains unclear, however, it is felt that they most likely represent hematogenous spread of benign uterine tumors. The diagnosis of BML is made following biopsy either by fine needle aspiration or wedge resection. Pathology typically demonstrates a smooth muscle phenotype with rare mitotic figures, as well as frequent estrogen and progesterone receptor positivity. Management of the disease is mediated through hormonal manipulation through the use of medical or surgical oophorectomy.
CONCLUSIONS: This case highlights a unique cause of multiple pulmonary nodules to be kept in mind in pre-menopausal patients without overt evidence infection or malignancy. It also demonstrates the use of both treatment modalities to achieve regression of the patient’s multiple pulmonary nodules.
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Reference #2 Abramson S, Gilkeson RC, Goldstein JD, Woodard PK, Eisenberg R., and Abramson N. Benign Metastasizing Leiomyoma: Clinical, Imaging, and Pathologic Correlation. AJR 2001; 176:1409-1413.
Reference #3 Pitts S, Oberstein EM, Glassberg MK. Benign metastasizing leiomyoma and lymphangioleiomyomatosis: sex-specific diseases? Clin Chest Med 25 (2004) 343 - 360
DISCLOSURE: The following authors have nothing to disclose: Kendra Hammond, Nidhi Undevia
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