Step by step approach to rare breast lesions containing spindle cells

Abstract

Differential diagnosis of spindle cell lesions of breast is challenging for certain reasons. The most important reason is the presence of cytological atypia and mitosis in all three conditions: reactive, benign, and malignant. Patients diagnosed with benign and malignant tumor/tumor-like lesions that had spindle cell components following the histopathological examination were included in the study. The patients' medical records were accessed to obtain the clinical history, follow-up notes, and radiological findings. Following histopathological, immunohistochemical, and clinical evaluations, the patients were diagnosed as follows: pseudoangiomatous stromal hyperplasia (PASH), bilateral desmoid-type fibromatosis (FM), adenomyoepithelioma (AME), myofibroblastoma (MFB), malignant phyllodes tumor (MF), high-grade AS, post-chemotherapy osteosarcoma (OS) + Paget's disease, and metaplastic carcinoma (MC). An algorithmic approach should be used in the diagnosis; cellular structure, presence and grade of atypia, growth pattern, mitotic activity, immunohistochemical staining, and clinical and radiological features should be evaluated together. Detection of some molecular changes can be useful in differential diagnosis.

Fine‐needle aspiration cytology of a mammary myofibroblastoma: A case report on the role of immunohistochemistry and cell block preparations and a review of the literature

“…The approach to spindle cell lesions of the breast remains full of pitfalls. In this regard, an algorithmic approach should be used in the diagnosis; cellular structure, presence and grade of atypia, growth pattern, mitotic activity, immunohistochemical staining, and clinical and radiological features should be evaluated together …”

Fibromatosis, a benign breast disease mimicking carcinoma. A case report

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Rare variant of metaplastic carcinoma of the breast: a case report and review of the literature

“…Findings of focal positivity for cytokeratin (AE1/AE3, CK5/6, CK7, and CK14) and the presence of S100 protein are in favor of this lesion. There may be a positive reaction for muscle markers such as calponin (86%) and smooth muscle actin (36%) [ 10 , 11 ]. p63 is a sensitive and relatively specific marker for epithelial cells [ 12 , 13 ].…”