Case Presentation: A 52-year-old female with a history of uterine leiomyomas presents with abdominal pain and vaginal bleeding for six months, acutely worsened over the past two weeks. Two months prior to the current admission, she presented to an outside hospital with menorrhagia that was attributed to known leiomyomas. She was discharged home on Norethindrone with temporary improvement of symptoms.
On presentation, the patient was afebrile and normotensive, but tachycardic and tachypneic with laboratory values notable for a hemoglobin of 7.4 g/dL, lactate dehydrogenase of 1279, and a lactate of 3.4.

A chest x-ray revealed multiple pulmonary lung nodules, and a subsequent chest CT demonstrated cannonball metastases in the lung parenchyma, as well as a partially loculated pleural effusion (Figure 1). A CT of the abdomen and pelvis was significant for a grossly enlarged uterus with dystrophic calcifications. Transthoracic needle aspiration of the lung nodule yielded pathology consistent with poorly differentiated leiomyosarcoma of presumed uterine origin.

The patient’s clinical status rapidly deteriorated with persistently elevated lactate, worsened tachypnea and tachycardia, and severe abdominal pain. Given the aggressive nature of her disease and limited treatment options, the patient was transitioned to hospice care and died peacefully on hospital day 25.

Discussion: Leiomyosarcomas represent a rare subset of uterine malignancies, comprising 1% of all uterine neoplasms and 20% of uterine sarcomas. Leiomyosarcomas are highly aggressive and malignant tumors with an estimated 5-year survival rate of 15-25% with an extremely high mortality rate associated with metastatic disease. These tumors are theorized to arise from leiomyomas, or benign fibroids, which is a common gynecological condition seen in 70-80% of women during their reproductive years. Given that both conditions present with isolated vaginal bleeding, it is a diagnostic challenge to differentiate leiomyosarcomas from leiomyomas, their more prevalent and indolent counterpart. Therefore, it is essential for internists to consider both diseases in the differential diagnosis for a woman presenting with menorrhagia, in order to ensure appropriate work-up and evaluation for malignancy. As such, it is recommended that all women over the age of 45 with abnormal uterine bleeding are referred to gynecologists for endometrial biopsy to further evaluate for underlying malignancy. Our patient’s menorrhagia was initially attributed to her longstanding history of uterine leiomyomas, though it was only upon evaluating this further that a far more aggressive condition – uterine sarcoma – was identified as the cause.

Conclusions: Uterine leiomyomas and leiomyosarcomas both present with menorrhagia; the former representing a common and benign condition, with the latter representing a rare, aggressive, and fatal malignancy. By remaining aware of these etiologies of menorrhagia, physicians can more readily identify, diagnose, and treat potentially aggressive malignancies.

IMAGE 1: Figure 1 (Cannonball metastases to the lungs)