Incidental benign metastasizing leiomyoma in a patient with bone sarcoma: a case report

Abstract

Background. The benign metastasizing leiomyoma is an exceptionally rare entity; it presents with ectopic leiomyoma nodules with a benign pattern. Symptoms vary according to the anatomic location. The diagnosis is histopathological, usually in patients with history of hysterectomy. Case Presentation. A 36-year-old female with 2-month history of left knee pain was diagnosed with bone fibrosarcoma. A CT scan showed pulmonary nodules. The patient started neoadjuvant chemotherapy. Conservative surgery of pelvic limb was achieved. A new CT scan reported pulmonary nodules that remained in relation to the previous CT. A nodule resection by thoracotomy and TOB (transoperative biopsy) was performed. The final pathology report described benign proliferative lesions consistent with benign metastatic leiomyoma. Conclusions. Benign metastatic leiomyoma is a rare condition presenting with uterine and extrauterine nodules most commonly in the lung. The diagnosis is histopathological. The surgical procedure must be reserved for selected patients.

Figure 1

((a) and (b)) Permeative pattern in distal femur; (c) malignant looking lesion is corroborated with a MRI. MRI: magnetic resonance imaging.

Figure 2

Pulmonary nodules (arrows) in both hemithoraces on a CT scan.

Figure 3

CT scan 3 months later reported multiple pulmonary nodules (arrows) that remain in number and dimension in relation to the previous CT.

Figure 4

Nonanatomic pulmonary resection of superior and inferior left lobe was performed by posterolateral thoracotomy.

Figure 5

Fibromuscular tissue growth with nonneoplastic ossification; immunohistochemistry nodules composed of cells, vimentin, AML, calponin, ALK1, a240, D, and Ki67 20%. AML: actina de músculo liso (smooth muscle actin).

Figure 6

Pelvic US shows uterine myoma in posterior wall of 30 × 25 × 20 mm. Two myomas in the interior wall.