We report a 51-year-old woman who presented to the emergency department with left-sided pleuritic chest pain 2 weeks after subtotal hysterectomy and bilateral salpingo-oophorectomy for a leiomyomatous uterus. Computed tomography scan of the chest revealed bilateral pulmonary nodules. Biopsy showed cytologically bland spindle cells without overt malignant features. Immunohistochemistry confirmed smooth muscle phenotype, in keeping with a clinicopathologic diagnosis of benign metastasizing leiomyoma (BML). BML does not frequently come to the attention of the emergency physician because it is rare and usually asymptomatic. When symptomatic, its clinical presentation depends on the site(s) of metastasis, number, and size of the smooth muscle tumors. Emergent presentations of BML are reviewed.
Benign metastasizing leiomyoma (BML) is an entity in which benign-appearing uterine smooth muscle tumors are associated with similar-appearing tumors at distant sites [
A 51-year-old woman, gravida 2 para 2, presented to the emergency department with a 2-day history of left-sided pleuritic chest pain. Two weeks prior, she underwent subtotal hysterectomy and bilateral salpingo-oophorectomy for a leiomyomatous uterus which was approximately the size of a 12-week gravid uterus. Ten years prior, she underwent a hysteroscopic myomectomy for a submucous leiomyoma. Her medical history was further remarkable for endometriosis, primary biliary cirrhosis, chronic cholecystitis, hypertension, hypercholesterolemia, and transient ischemic attack. On physical examination in the emergency department, she was afebrile with a blood pressure of 150/87, heart rate 60/min, respiratory rate 18/min, and oxygen saturation 99% on room air. She had a BMI of 33, normal heart sounds, and clear chest on auscultation. ECG was normal. ABG showed pH 7.41 and pCO2 39 mmHg. She had a normal complete blood count, basic metabolic panel, and troponin. D-dimer was 1.2
PA chest radiograph: there is a 1.3 cm nodule within the left lower lobe (arrow), projected lateral to the left cardiac border.
CT pulmonary angiogram performed the same day as the chest radiograph. (a) Axial image (lung windows): left lower lobe soft tissue nodule corresponding to the abnormality on the CXR (arrow) demonstrates no internal calcification or cavitation. Six other similar-appearing nodules of varied sizes were scattered throughout the lungs. (b) Coronal MIP image (soft tissue windows): two well-circumscribed left lower lobe nodules (arrows).
Subsequent mammogram and CT scan of the abdomen, pelvis, and head showed no other deposits or suggestion of a primary malignancy. She was taken to the operating room for diagnostic wedge resection of one of the nodules by VATS and a hilar lymph node biopsy. She tolerated the procedure well and was discharged from hospital on the third postoperative day without any complications. Microscopic examination of the resected nodule showed a a well-circumscribed, nonencapsulated tumor with a smooth pushing border to the surrounding lung parenchyma (Figure
(a) A well-circumscribed tumor with a pushing border to the lung parenchyma (green arrow) (H&E, 40x). Note entrapped bronchiolar epithelium encircled by collagen (red arrows). (b) Bland smooth muscle cells without cytological atypia (H&E, 100x). (c) Diffuse staining (brown) for SMA (12.5x). Note negative staining (white) of collagen and bronchiolar epithelium in the tumor. (d) Diffuse staining (brown) for desmin (12.5x). There was negative tumor cell staining for p16, p53, WT-1, CD10, CD31, HMB-45, CD117/c-kit, and ALK-1 (not shown).
BML is rare, despite the high incidence of uterine leiomyomas in the general population. It occurs in women at an average age of 47 years, most of whom have undergone hysterectomy or myomectomy for uterine leiomyomas [
BML lung nodules typically do not calcify or enhance after intravenous contrast administration [
The exact pathogenesis of BML is unknown. Three hypotheses have been proposed [
Investigation and management in the emergency department must be tailored to the particular BML presentation. As mentioned, BML involving the lung is usually asymptomatic. Its presentation as pleuritic chest pain is uncommon and invokes a broad differential diagnosis [
Diagnostic algorithm for pleuritic chest pain (modified from Kass et al. [
Suspected lung metastases of unknown primary should be referred for biopsy. There is no standardized management approach for lung involvement by BML. Because most lesions stay constant in size for a long time, a wait-and-see strategy consisting of periodic serial imaging is usually reasonable. This strategy also allows detection of lesions suspicious for lung adenocarcinoma, which may be present concurrently among the BML nodules [
In conclusion, emergency physicians should be aware of BML and its range of clinical presentations. Although BML involving the lung is usually asymptomatic and found incidentally, it may be present with emergent symptoms. BML should be considered in women of reproductive age with current or previously diagnosed uterine smooth muscle tumor(s) who are found to have multiple pulmonary nodules in the absence of pertinent history, risk factors, or localizing findings suggestive of metastasis from other primary site.
Arterial blood gas
Anaplastic lymphoma kinase-1
B-cell lymphoma-2
Body mass index
Benign metastasizing leiomyoma
Cluster of differentiation
Computed tomography
Computed tomography pulmonary angiogram
Chest X-ray
Electrocardiogram
Fibrinogen equivalent units
Hematoxylin and eosin
Human melanoma black-45
Myocardial infarction
Maximum intensity projection
Nonsteroidal anti-inflammatory drug
Posterior-anterior
Pulmonary embolus
Smooth muscle actin
Video-assisted thoracic surgery
Wilms tumor-1.
Written consent has been obtained from the patient and is available upon request.
The authors declare that there is no conflict of interests regarding the publication of this paper.