Unravelling of diagnostic dilemma in selected unusual cases of spindle cell lesions of breast.

OBJECTIVES

Spindle cell lesions of the breast (SCLB) are very rare and represent an interesting diagnostic problem due to wide differential diagnoses. Diagnosing these lesions is problematic but important when encountered in a core needle biopsy, as different entities have different plan of treatment. In the histologic assessment of spindle cell lesions, the simplified approach is to evaluate the spindle cells and the accompanying epithelial cells.

METHODS

Patients diagnosed with benign and malignant tumors that had a predominant spindle cell component on histopathological examination were included in our study. The patients' medical records were accessed to obtain the clinical history, follow-up notes, and radiological findings.

RESULTS

The spindle cell lesions of the breast included a varied diagnosis ranging from benign/borderline phyllodes tumor, pseudoangiomatous stromal hyperplasia (PASH), mammary fibromatosis to malignant etiologies-like metaplastic spindle cell carcinoma. An algorithmic approach was employed for diagnosing SCLB based on cellular composition, presence and grade of atypia, growth pattern, and mitotic activity in conjunction with immune-histochemical features and clinical and radiological features. WHO classification of breast lesions was used in reaching a conclusive diagnosis. By studying the SCLB, the diagnostic difficulties faced on interpreting core needle biopsy versus the histopathological examination of excisional biopsy in each case were highlighted in our study.

CONCLUSION

Keeping in mind the rarity of the lesion, careful histologic examination in spindle cell lesions to identify accompanying epithelial element, focal cohesiveness within the spindle cell area, and heterologous elements is of great value along with judicious use of immuno-histochemistry, which allows correct diagnosis to be made in the majority of cases, thus facilitating optimal treatment.