Peripheral nerve sheath tumors of the breast.

Benign and malignant peripheral nerve sheath tumors can involve the breast, presenting as masses in the dermis, deep breast parenchyma or axillary soft tissue. Although the histologic features are frequently characteristic, diagnosis can be challenging on core needle biopsy, and the differential diagnosis includes a variety of other benign and malignant spindle cell lesions of the breast. Here, we review the key clinical and pathological features of breast schwannoma, neurofibroma, granular cell tumor, and malignant peripheral nerve sheath tumor.