Benign Metastasizing Leiomyoma:
View cases of benign metastasizing leiomyoma
Clinical:
Benign metastasizing leiomyoma is a very rare disorder [4]. The condition is felt to represent hematogenous seeding to the lungs from a benign uterine tumor [4] or a very low grade leiomyosarcoma of the uterus in a post-hysterectomy patient. The tumor may gain venous access from surgical trauma during hysterectomy [4]. Nodules develop between 3 months to 20 years following the procedure [4]. It is seen exclusively in females and is characterized by multiple, bilateral pulmonary leiomyomas ranging in size from a few millimeters to several centimeters. The clinical course is typically indolent [4] and cavitation of the lesions occasionally occurs [5]. There is an overall good long term prognosis because the lesions are generally hormonally sensitive (containing estrogen and progesterone receptors [5])- with decreased estrogen causing growth inhibition. Treatment with oophorectomy and long term progesterone are quite successful for disease therapy. [1]
Metastatic leiomyomas identified in men or pediatric patients are not hormonally sensitive and do not respond well to any form of chemotherapy. They most likely reflect pulmonary metastases from a low grade primary leiomyosarcoma. Histologically, the cellularity and mitotic indices are similar to the lesions found in benign metastasizing leiomyomas, but their growth pattern is more invasive. Surgical excision is the treatment of choice in these patients.
Multiple pulmonary fibroleiomyomatous hamartomas are exceedingly rare and this diagnosis can only be entertained when no primary source for the lesions can be identified.
Primary leiomyomas and leiomyosarcomas may also occur in the lung, but these are also exceedingly rare and are typically solitary lesions [2]
REFERENCES:
(2) NEJM, 2 Jan. 1958: p. 12-17
(3) Radiographics 1998; Maredia R, et al. Residents' teaching files: Benign metastasizing leiomyoma in the lung. 18: 779-782 (No abstract available)
(4) AJR 2001; Abrahamson S, et al. Benign metastasizing leiomyoma: Clinical, imaging, and pathologic correlation. 176: 1409-1413
(5) Radiographics 2008; Fasih N, et al. Leiomyomas beyond the uterus: unusual locations, rare manifestations. 28: 1931-1948
