Malignant PT is rare lesion of the breast that can mimic benign masses such as fibroadenomas, on clinical diagnosis, but is characterized by a typical rapid growth. PTs usually occur in middle-aged women ranging in age from 35 to 55 years, with an average presentation at 45 years [4]. PTs are composed of epithelial elements and a connective tissue stroma with higher stromal cellularity. A malignant PT is distinguished from a benign/borderline PT by the presence of marked stromal cellularity, cellular atypia and mitotic activity in at least 10/10 high-power fields [10].
The clinical presentation and the radiographic findings of malignant PT are strikingly similar to those of benign lesions, such as fibroadenoma, or even benign PT, thus, making it quite challenging for clinicians to diagnose or even to suspect the disease at an early stage. Although routine breast biopsy may not be warranted, it is crucial for clinicians to consider and include PT in their differential diagnosis. Moreover, it is also evident that clinicians cannot rely completely on radiographic findings.
According to the National Comprehensive Cancer Network (NCCN) guidelines for breast cancer, the management of PTs with a size > 3.0 cm is surgical excision with clean margins (≥ 1.0 cm) without axillary staging, regardless of whether the tumor is benign, borderline, or malignant [11]. Many other studies have supported the contention that margins that are ≤ 1.0 cm are associated with a higher recurrence rate, ranging from 16.7 to 40% [4, 12].
The prognosis of PTs is variable, with local recurrence rates ranging from 10 to 40% (average 15%) and distant metastases occurring in 10% of all PTs and up to 20% of malignant PTs [13]. Survival after metastatic disease is poor, with various case series reporting a median survival ranging from 4 to 17 months, with large variability based on the site of the metastatic disease [14]. Other large prospective studies have reported 5-year disease-free survival rates of 96% for benign PTs and 66% for malignant PTs [15]. Most sarcomas metastasize hematogenously, and the incidence of axillary lymph node involvement in malignant PTs ranges from 1.1 to 3.8% [16].
There is currently no consensus regarding the recommendations for radiotherapy, hormonal therapy, and systemic chemotherapy for malignant PTs. To date, no double-blinded, multicenter study has been performed on this subject. Most case reports and studies describe treating these tumors exclusively with wide local excision, in according with the current NCCN guidelines. As PTs are considered as soft-tissue sarcoma, adjuvant chemotherapy with doxorubicin plus dacarbazine may provide some benefits to patients with large (> 5.0 cm), high-risk tumors [17]. A deeper investigation of the addition of adjuvant therapy for large aggressive malignant cases of PT may prove to be fruitful [18]. Recently, doxorubicin and ifosfamide therapy has been reported to be effective to treat metastases of malignant PTs [19, 20]. In accordance with previous reports [19, 20], we administered AI therapy using 60 mg/m2 doxorubicin and 10 g/m2 ifosfamide in each course.
Because there are not many reports of malignant cases of PT, the data available are insufficient to calculate fully the statistics of the survival rate associated with these tumors. Past case reports and studies have suggested that the prognosis of malignant PT of the breast is usually poor, while the overall prognosis of benign PT is good [14, 21].
The early diagnosis and staging of PTs are pivotal not only for improving the overall outcome of the disease after treatment, but also to promote the quality of life of the patient by causing less disfiguration. While the breast cancer screening guideline suggests that women over 40 years of age should begin routine mammograms to detect the presence of breast cancers, PTs can occur a decade before this minimum screening age as they occur during the third or fourth decades of life. Moreover, if the patient suspects that the lesion exhibits growth within 6 months to a year of initial detection, it should be considered for further workup.