Benign metastasizing leiomyoma
Benign metastasizing leiomyomas are a rare metastatic phenomenon that is observed when a pelvic leiomyoma is present.
Women who have undergone hysterectomy for leiomyomas are most commonly affected.
Patients are usually asymptomatic at presentation. A history of a hysterectomy for uterine leiomyoma may be indicative. Occasionally symptoms of chest pain, shortness of breath, and cough may be present.
The condition is characterized by multiple well-differentiated leiomyomas at sites distant from the uterus. The lesions are histologically identical to their uterine counterparts. It is generally considered that the lesions are a result of haematogenous metastases from benign tumors although some support the hypothesis of multiple independent foci of smooth muscle proliferation.
Although most commonly seen in the lungs 2, other sites of involvement include lymph nodes, peritoneum, and retroperitoneal structures.
Imaging features are often non-specific 3.
When there is lung involvement this may be seen as multiple nodules and pulmonary masses on chest radiography and/or CT. Mediastinal and hilar lymphadenopathy is rare. Cavitation of lesions may occasionally take place and rarely may be accompanied by a pneumothorax. Calcification is rare. Following intravenous contrast, the lesions usually enhance homogeneously 3. Occasional cases have been reported with a miliary pattern or a pattern simulating interstitial lung disease.
Treatment and prognosis
The clinical course is typically indolent and spontaneous resolution has been described.
History and etymology
The condition was first described by P E Steiner in 1939 4.
For lung nodules, there can be a wide differential which includes: