Pathology

Leiomyosarcoma

Nodular fasciitis

Spindle cell carcinoma

Biology

CD34

Immunohistochemistry

Fibromatosis

Leiomyoma

Fibroma

Differential diagnosis

Dermatofibrosarcoma protuberans

Stem cell

Spindle cell sarcoma

Solitary fibrous tumor

Schwannoma

Genetics

Medicine

Pathologica

The diagnosis of bland-looking spindle cell lesions of the breast is often challenging because there is a close morphological and immunohistochemical overlap among the different entities. The present review will discuss reactive spindle cell nodule/exuberant scar, nodular fasciitis, inflammatory pseudotumor, myofibroblastoma (classic type), lipomatous myofibroblastoma, palisaded myofibroblastoma, benign fibroblastic spindle cell tumor, spindle cell lipoma, fibroma, leiomyoma, solitary fibrous tumor, myxoma, schwannoma/neurofibroma, desmoid-type fibromatosis, dermatofibrosarcoma protuberans, low-grade fibromatosis-like spindle cell carcinoma, inflammatory myofibroblastic tumor and low-grade myofibroblastic sarcoma arising in the breast parenchyma. The pathologist should be aware of each single lesion to achieve a correct diagnosis to ensure patient a correct prognostic information and therapy. Accordingly representative illustrations and morphological/ immunohistochemical diagnostic clues will be provided.

Practical approach to diagnosis of bland-looking spindle cell lesions of the breast