A 35-year-old female presented with sudden enlargement of the left breast. The female subject underwent bilateral breast augmentation surgery with 200 mL saline-filled silicone prostheses two years prior. She had no complications related to her initial surgery and both breasts remained symmetrical in shape and size until the day before the symptom started. There was no history of trauma but she mentioned, her husband squeezed her breast during sexual activity the previous evening.

At physical examination, the clinician found a marked enlargement of her left breast. The patient presented mild tenderness but there was no heating sensation or redness of the skin. Laboratory tests showed a low hemoglobin level (8.9 g/dL) and low hematocrit (24.8%). The prothrombin time and platelet level was within the normal range.

Ultrasound (US) evaluation was performed. Due to marked enlargement of left breast, a conventional linear US probe was inappropriate to evaluate the lesion. Instead of linear probe, a convex probe was used during the examination. US showed a large, well-circumscribed lesion with heterogeneous echogenecity, which was confined to the lower outer quadrant (LOQ) and lower inner quadrant (LIQ) of her left breast (Fig. 1A). The silicone prosthesis was partially surrounded by the large heterogeneous echoic lesion. The margin of the prosthesis showed a slight irregularity, thus suggesting that there might be rupture of the prosthesis. A Doppler US scan revealed that there was no trace of blood flow at the large heterogeneous echoic lesion (Fig. 1B). According to the US findings and the symptoms, we presumed that the patient had a large hematoma with small rupture of the silicon prosthesis in her left breast.

The patient underwent a contrast enhanced computed tomography (CT). The chect CT was performed before and after the administration of intravenous contrast material. The non-contrast CT scan revealed a large hematoma, which was formed around the left silicone prosthesis and extended to the lower region of the left breast (Fig. 1C). The enhanced CT scan showed an active extravasation of contrast material at the inner portion of the hematoma, which suggested arterial bleeding (Fig. 1D). The patient was diagnosed with a huge hematoma with active arterial bleeding.

Surgical exploration was performed. At the operation field, surgeons confirmed the active arterial bleeding from the left internal mammary artery (IMA) with approximately 1L of hematoma around the bleeding site and silicone prosthesis. They ligated the bleeding site with vicryl, and then removed the hematoma and silicone prosthesis. The postoperative course was uneventful.

Breast augmentation surgery is a world-wide, common cosmetic procedure. A hematoma is a well known complication during the early postoperative period (1). Hematomas have been reported to occur in 1.5% to 10.3% of individuals having undergone breast augmentation in the early postoperative period; especially in the first few days after surgery (14). However, only about 20 cases of late postoperative complication have been reported in the English literature since the first case report in 1975 by Georgiade et al. (567). These cases reported a sudden or chronic hematoma of the breast after 6 months to 22 years after the augmentation surgery, with or without a leading mechanical irritation (67).

Because of the limited number of previously reported cases, definite causes of the late hemorrhage have not been established. Georgiade et al. thought that corticosteroid administration was the cause of the late erosion of the medium-sized artery (5). In polyurethane covered implants, a prolonged inflammatory reaction and increased capillary permeability may be the pathogenesis of late hematomas (2). However, according to an updated report, capsular microfractures with the rigidity of the capsule, preventing the retraction of damaged blood vessels, lead to continued bleeding (7). Mechanical irritation such as squeezing, compression, or blunt trauma on the augmented breast might be the cause of injury on these fragile vessels around the implant, which may cause a late hematoma. In our case and two cases which van Rigssen et al. had reported, the direct triggering factor for hematoma development was caused by squeezing of the breast (7).

Injury to the internal mammary artery is the most common cause of late hematomas after breast augmentation surgery. Braatz et al. described the CT findings of several cases with IMA injury (8). All the four cases were an IMA injury developing from a hematoma of the anterior mediastinum. a hematoma of the breast can occur as a result of a seat belt injury of the breast of restrained passengers in a traffic accident. There was a case of active arterial bleeding of the breast in a seat belt injury, in which an angiogram revealed the source was a horizontal branch of the internal mammary artery (3). In this case, there was a large hematoma with extravasation of contrast material in the inner portion of the injured breast on CT scan. Therefore, we could presume that the injured vessel of our patient must be perforating branches of the IMA rather than the IMA itself. In this case, the patient underwent flow-directed embolization with a gelatin sponge and a coil, unlike our patient, who underwent exploratory surgery to remove the hematoma and prosthesis.

In summary, late hematoma formation after breast augmentation surgery is a very rare condition but may be a life-threatening. Early evaluation with US and contrast-enhanced CT is very important to document a large hematoma around the silicone prosthesis associated with active arterial bleeding.