Parenchymatous pulmonary endometriosis - metastases of a low-grade endometrial stromal sarcoma?

Based on the data of a case of parenchymatous endometriosis of the lung in which three and a half years later a low-grade endometrial stromal sarcoma of the uterus was diagnosed the origin of this disease is discussed. The follow up of this patient gave the impression that the pulmonary nodules were early metastases of low-grade endometrial stromal sarcoma, which was initially not detected in the routine gynecologic examination. Furthermore, as histological and immunohistochemical examinations are not sufficient to distinguish reliable between endometriosis of the lung and pulmonary metastases from low-grade endometrial stromal sarcoma. In literature, in none of the few cases of parenchymatous pulmonary endometriosis a hysterectomy was performed to exclude a low-grade endometrial stromal sarcoma. Thus, parenchymatous pulmonary endometriosis nodules might be metastases and their occurrence should cause the treating physician to consider a distant metastatic spread from low-grade endometrial stromal sarcoma.