Breast sarcoma is a rare condition that occurs independently of other malignancies and without previous irradiation. The management of this condition remains controversial due to its infrequency and limited correlation between grading and outcomes. Advances in diagnostic methods, including immunohistochemistry, have improved identification accuracy. Breast sarcomas constitute a small fraction of all primary breast malignancies, originating from mesenchymal tissue.1 Due to the lack of agreement on the exact definition of breast sarcoma, different studies have varying criteria for inclusion, with some authors excluding cystsarcoma phyllodes because of the presence of both epithelial and stromal components. Breast sarcomas consist of different types, including angiosarcoma, malignant fibrous histiocytoma, stromal sarcoma, liposarcoma, leiomyosarcoma, dermatofibrosarcoma protuberans, osteosarcoma, fibrosarcoma, and rhabdomyosarcoma. Since primary breast sarcomas are rare and mostly documented through case reports or small series, the understanding of this entity is still limited. The management of primary breast sarcomas poses challenges, ranging from the absence of agreement on the ideal surgical approach and the necessity for adjuvant chemoradiation to the critical role of achieving an adequate resection margin. Overall, the prognosis for breast sarcoma is unfavorable. In this report, we present cases of primary stromal sarcoma of the breast with varying histological differentiations, shedding light on the diagnostic complexities involved in these cases

Breast cancer is a highly common cancer type that mostly affects females. It has two primary forms, namely carcinoma and sarcoma. Carcinomas arise from the epithelial component of the breast, while sarcomas, which are rare, develop from the stromal (connective tissue) components of the breast. Primary breast sarcomas are very rare, and only a few hundred cases have been documented in the literature so far. ^{2, 3, 4, 5}

Primary breast soft tissue sarcomas tend to affect women in their fifth or sixth decade of life. Male cases make up less than 5% of these tumors. Reported 5-year survival rates range from 14% to 91%. Possible risk factors include previous radiation exposure therapy, chronic lymphedema, preexisting fibroadenomas, and genetic conditions like neurofibromatosis or Li-Fraumeni syndrome ^1, although more research is needed to confirm these associations.

Unilateral breast mass with rapid size increase and discoloration of the overlying skin is the typical presentation of primary breast sarcoma. FNAC can detect malignancy most of the time, but alone may not be sufficient in all cases. This is especially true for larger masses with varying consistency. In such cases, it should be followed by core biopsy if a diagnostic dilemma arises. Core biopsy is thus crucial for accurate diagnosis owing to the substantial size and atypical presentation of the mass. Fine needle aspiration is not accurate enough for categorization, though it can give a diagnosis of malignancy, and excisional biopsy should not be performed until other diagnostic attempts have failed.6, 7, 8 In our study, all cases initially underwent FNAC, but due to the mass's increased size, the diagnosis was inconclusive. As a result, further histopathological examination was performed for each case.

The American Joint Committee on Cancer staging system ⁹ is commonly used for staging breast sarcomas in soft tissue sarcoma. This system takes into account different variables including histological grade, tumor size, lymphatic involvement, and distant metastasis.10 These tumors tend to recur and have a poor prognosis. In four cases, the diagnosis was missed in FNAC due to the presence of a large tumor mass. Among them, two were initially thought to be invasive ductal carcinoma, one was suggestive of malignancy, and one was thought to be phyllodes. However, on histopathological examination, all four cases were found to be sarcoma of the breast.

FNAC may not always provide representative tissue samples, leading to potential false diagnoses.

It's recommended to complement FNAC with histopathology and immunohistochemistry for a conclusive diagnosis. This can be achieved with the preparation of a cell block, on which immunohistochemical evaluation may be performed for definite categorization. The treatment approach for breast sarcomas follows a multidisciplinary model, but there's currently no definitive agreement. Mastectomy without axillary lymph node dissection is the preferred treatment, with axillary dissection avoided unless there are clinically positive nodes. ^{11, 12} Achieving a negative surgical margin is a crucial determinant for both local recurrence and overall survival in these cases. High-risk cases may benefit from adjuvant or neoadjuvant chemotherapy, as well as radiotherapy. These treatment options should be taken into consideration. Several factors, including tumor grade, size, and histological type, affect the overall prognosis. Diligent follow-up is essential, as tumors measuring less than 5 cm are associated with a better outcome, underscoring their significance. In our study, all tumors were larger than 5 cm, and only one case could be followed, which presented with tumor recurrence.

Diagnosing sarcoma of the breast through FNAC is a challenge due to its rarity. Although spindle cells with nuclear atypia are suspicious findings on the smears, definite diagnosis may be missed due to the similarity with entities like phyllodes. So, all FNACs should be complemented by cell block or followed up with biopsy for histopathology and IHC to understand its line of differentiation for definite diagnosis and better prognostic outcome.