Ultrasound-guided fine needle aspiration cytodiagnosis of leiomyosarcoma metastatic to the breast. A case report.

BACKGROUND

Leiomyosarcomas are characterized by slow growth and late metastasis and most often involve the lung, liver and subcutaneous tissue. Metastasis to the breast is rare, with only four cases published in the English-language literature to date. Because of its rarity and the prolonged time interval between the diagnosis of the primary tumor and involvement of distant sites, accurate diagnosis of these tumors can be challenging. Evaluation of the cytomorphologic features of the tumor, ancillary immunocytochemical staining and detailed medical history of the patient are essential to making a correct diagnosis.

CASE

A case of leiomyosarcoma metastatic to the breast occurred in a 60-year-old woman whose primary uterine leiomyosarcoma had been resected 10 years before the diagnosis of the metastasis. Fine needle aspiration performed with ultrasound guidance yielded a moderately cellular specimen composed of minimally pleomorphic spindle cells with smooth, blunt-ended nuclei arranged in an interlacing pattern. Immunocytochemical staining for muscle-specific actin confirmed the smooth muscle origin of the neoplasm.

CONCLUSION

The results of cytomorphologic analysis and immunocytochemical staining performed after fine needle aspiration and the patient's history of primary uterine leiomyosarcoma allowed us to correctly diagnose metastasis to the breast and avoided inappropriate management of the metastasis as a primary tumor.