Breast hematomas are found in trauma, such as surgical and anticoagulant induction or abnormal blood clotting caused by blood diseases. In blunt trauma to the chest, breast hematoma is rare, with a rate of less than 2%[2]. The presence of a breast hematoma should be suspected when subcutaneous ecchymosis and painful masses are present. Hematoma can lead to necrosis of the skin, which may require surgical drainage. Severe hematomas are common in patients with clotting disorders or taking anticoagulants, and reports have shown that the use of combined anticoagulants with blunt trauma in the breasts causes huge hematomas, which require emergency surgery[2]. Most traumas are self-healing, therefore, if patients’ signs or symptoms persist for more than 4–6 weeks, then their risk of breast cancer must be carefully evaluated [1]
Basic imaging examinations for breast masses included ultrasound, mammography and MRI. Mammography were postponed or omitted due to the great pain brought to patients in acute phase and ultrasound was more commonly used in clinical practice, while ultrasound showed different manifestations in different phase. In the acute stage, hematoma is manifested as hypoechoic hematoma, with acting with coagulation function, which tends to be pure hyperechogenicity [3]. In this case, the manifestations of carcinomas in the surgically resected specimens were as follows: localized thickening of the cyst wall and protrusion into the lumen with unclear boundaries; invasive carcinoma of the breast accompanied by cystic changes; while in the ultrasound examination two months after the trauma, there was also a cystic solid mass. Combined with the medical history, the radiologist considered it as the organizing manifestation of hematoma. This also suggests that a single ultrasound is flawed and mammography is complementary to ultrasound examination. When the patient has an organized hematoma that will always show mammographically as a mass of high density, a biopsy is necessary for complete evaluation.
But the clinician's inherent impression of a simple breast hematoma ignored the mammography’s indication. Breast trauma would lead to changes similar to malignant breast tumors, and there was no distinguishable from malignant tumors when ultrasound and mammography were used for follow-up of breast hematomas and fat necrosis, while dynamic MRI could provide important clues [4].
The significance of enhanced CT in breast hematoma is mainly to determine the bleeding scope and the amount of bleeding. Regarding the simple traumatic non-neoplastic breast hematoma, CT examination mostly showed the hematoma in the posterior breast space. In the reported cases, the amount of bleeding was large and rapid, and arterial bleeding was considered after the final operation [2, 5]. In tumor bleeding, parenchymal blood vessel hemorrhage is considered to break into the cyst cavity or to form the cyst cavity in the catheter. Due to the limited space, self-compression and hemostasis are more common. After puncture and drainage, the pressure decreases and the parenchymal vessels bleed again. There are also cases of spontaneous rupture and hemorrhage of encapsulated papillary carcinoma reported in the case report, with the increase of hematoma within a few days, huge tension causing skin necrosis and massive rupture of hemorrhage, and emergency surgical treatment is required. Therefore, the amount of bleeding of breast tumors with cystic components can also be large, which is worthy of surgeons' attention [6]. In two situations, a biopsy is necessary for complete evaluation: when there is absorption and the residual area presents a focal distortion of the parenchyma, or when there is not any absorption, in which the patient has an organized hematoma that will always show mammographically as a mass of high density.
Although a history of both cancer and trauma has been reported, there have been few studies on whether trauma causes cancer. Although wound healing and tumor growth share common physiological mechanisms, such as overexpression of cytokines and growth factors. Experimental studies have shown that the biochemical environment for wound healing is conducive to tumor growth. But we now think of traumatic breast cancer rupture as the cause of hematoma, not breast trauma as the cause of breast cancer considering the short course of the illness [4]