Breast metastases from a malignant peripheral nerve sheath tumor of the kidney: An unusual presentation

Abstract

Malignant peripheral nerve sheath tumors (MPNSTs) are extremely rare soft tissue sarcomas of ectomesenchymal origin. They are commonly seen in association with neurofibromatosis type 1 (NF-1), but can also occur without a history of NF (isolated MPNST). MPNSTs are most commonly located on the extremities (brachial and sacral plexus), head and neck, and trunk regions and are rarely reported in genitourinary organs. These tumors are aggressive, with a high recurrence rate and distant metastases. MPNST involving the kidney is extremely rare, and review of the literature using PubMed from 2001 to 2014 revealed eight cases of MPNST involving the kidney (seven, primarily involving the kidney and one metastatic MPNST of the kidney). Herein, we describe a case of breast metastases from an MPNST of the kidney without a history of NF-1. The patient was initially diagnosed with a spindle cell neoplasm of the kidney with peripheral nerve sheath differentiation. Eventually, the patient developed a right breast mass that was diagnosed as metastatic MPNST. The patient refused any kind of treatment and died 6 months later in hospice care.

Imaging Findings of Breast Metastasis from Malignant Peripheral Nerve Sheath Tumor of Mediastinum: A Case Report

“…MPNSTs are most commonly located in the trunk, extremities and head and neck ( 1 ). However, MPNSTs involving the breast are rare ( 2 3 4 5 6 7 ), and in particular, breast metastasis is extremely rare ( 8 9 ).…”

“…To our knowledge, there is only one case demonstrating mammographic and CT findings of metastatic MPNST in the breast. That was from a kidney MPNST, and appeared as a circumscribed, oval hyperdense mass on mammography and a peripherally enhancing mass on CT ( 8 ). Because studies evaluating the imaging findings of breast MPNST are very limited, it is difficult to differentiate the imaging characteristics of primary and metastatic MPNST in the breast.…”