Vascular Breast tumors: angiolipoma and hemangioma
"Vascular" means "related to blood vessels", so a vascular or 'vascularized' tumor is one which contains many blood vessels and is richly supplied with blood. There are often increased vascular components in many different kinds of breast tumors, including breast cancer tumors, but the classification of 'vascular breast tumors' refers basically to two benign tumors, not associated with malignant breast carcinoma or other common fibrous breast changes. These are angiolipoma, and hemangioma, and both can occur anywhere in the body and rarely occur on or within the breast.
An angiolipoma is essentially a breast lipoma (or fat tissue tumor) with prominent vascular features, while a hemangioma is pretty much just a buildup of blood vessels. There is a third possibility, however, of a malignant vascular tumor called an 'angiosarcoma', which can also occur within the breast. It is important therefore to arrive at a secure differential diagnosis. Clinically palpable vascular breast lumps are usually quite obvious due to their red or bruise-like appearance. However if they are discovered mammographically and seem a bit lower in the breast tissue, it can be a bit more of a concern and a bit more of a challenge diagnostically.
It is estimated that about 2/3 of all vascular breast tumors turn out to be malignant, (most likely angiosarcomas). The location of the vascular breast tumor can often be indicitive of it's malignant or benign nature. From an anatomical perspective, breast tissue is located between the anterior and posterior layers of the superficial pectoral fascia (the outer chest 'pecs' as it were). Most benign vascular breast tumors such as angiolipomas and hemangiomas will develop in the subcutaneous fat ('subcutaneous' means the lowest or bottom layer of the skin, essentially) just in front of the pectoral fascia muscle, and not within the breast parenchyma itself. (Parenchyma refers to the essential 'nuts-and-bolts' of a functioning organ, in this case, the breast ducts, glands, and the nipple ). Most vascular breast tumors which occur within the breast parenchyma turn out to be malignant angiosarcomas. Tumor size can also be an important characteristic for distinguishing angiosarcomas from hemangiomas. Angiosarcomas of the breast are rarely smaller than 2cm in diameter, while breast hemangiomas are almost never larger than 2cm.
Hemangioma of the breast
A hemangioma is essentially an abnormal buildup of blood vessels in the skin or internal organs, and they are usually diagnosed by physical examination. If they appear on the surface of the skin, they will often look like a 'ripe strawberry'. If breast hemangiomas occur 'just beneath' the skin, they will usually present as a 'bluish' swelling. Hemangiomas are generally very soft and 'squishy' to the touch. Breast hemangiomas are completely benign, but curiously, they have been found in about 1.2% of breast mastectomy specimens, and in about 11% of autopsies of women who have died due to confirmed breast cancer. This has led to some speculation that breast hemangiomas with atypical features might somehow be related to breast cancer or increased breast cancer risk, but there is no widely accepted scientic evidence to support this assertion. Breast hemangiomas may occur in both men and women, but for some reason they are about 3 times more common in women, leading to some speculation that their development in adults might in some cases be related to estrogen levels.
Two basic types of breast hemangiomas: capillary and cavernous
Breast hemangiomas are thought to be caused by a proliferation of vascular endothelial cells. They are most often associated with either infants or juveniles, and tend to occur on the skin or in the head and neck region. These 'conventional' and typically childhood related hemangiomas, which can nonetheless occur in or on the breast at virtually any age, are often broken into two distinct types which are based on the size of the blood vessels involved. "Capillary" breast hemangiomas tend to have very small blood vessels, while 'cavernous' breast hemangiomas are jumbled growths of blood vessels fed by numerous tributary arteries (which makes them very difficult and risky to remove surgically).
Small, incidental Breast hemangiomas are sometimes called perilobular hemangiomas
Microscopic breast hemangiomas (undetected by clinical or mammographic examination) have also been known to be found in mastectomys of women with confirmed breast carncinoma. These tiny breast lesions (2 mm or less) consist of a meshwork of thin-walled, dilated vascular channels. Sometimes they develop within a breast lobule, or else in the extralobular mammary stroma. There can be atypical features such as hyperchromatic nuclei and focal anastomoses, but no firm connection has been made between atpyical perilobular breast hemangiomas and malignant breast cancer.
Radiological appearance of breast hemangiomas
Mammographically, a hemangioma will usually appear as a well-circumscribed oval or lobular shaped lesion, which may contain macrolobulated margins, that may contain calcification. A radiologist will probably interpret a breast hemangiomas as a BI-RADS classification of category 3, or 'probably benign', mostly due to 'heterogeneously dense' parencymal breast tissue. Sonographically, most breast hemangiomas also appear oval in shape, isodense, and often with well-circumscribed margins, but sometimes with poorly defined margins. Breast hemangiomas tend to have nonhyperechoic, (i.e., hypoechoic, isoechoic, or complex) echotextures, but there is quite a bit of variability in this regard. The relative echotextural heterogeneity could be related to the presence of multiple small vascular channels that are often associated with breast hemangiomas. The ultrasound image of a breast hemangioma shown below show a heterogeneous, ill-defined, superficial, lobulated mass.
A breast angiolipoma is a variant of a breast lipoma. Lipomas are benign tumors which are essentially proliferations of fat tissue, while a breast angiolipoma is basically a lipoma with an unusually large number of vascular channels. Angiolipomas of the breast are very slow growing tumors, but they can be painful. Angiolipomas tend to occur multiply, and are most commonly found in the trunk and neck region, or the extremities, and rarely within the breast. Angiolipomas, which can also be termed 'lipoma cavernosum", most frequently develops just after the onset of puberty, but breast angiolipomas can develop in adults as well, right up into old age.
breast angiolipomas may be painful
The typical clinical presentation of a breast angiolipomas is of a painful, tender, and poorly marginated mass. Sometimes there can be nerve compression associated with angiolipomas, and this can result in neurological deficits. When breast angiolipomas are situated a little deeper within the breast an only visible mammographically, there are usually no overlying skin changes. The cause of breast angiolipoma is completly unknown, and they have not been known to undergo malignant transformation.
Two subtypes of breast angiolipoma: infiltrating and noninfiltrating
Two basic sub-types of breast angiolipomas are often described. These are the 'noninfiltrating' type of breast angiolipoma, which is actually more common in men, and the 'infiltrating' type of angiolipoma of the breast, which occurs in both children and adults of both sexes. Infiltrating breast angiolipomas are quite rare, and may infiltrate extensively into surrounding fibrocollagenous tissues, muscles, and nerves. Neither type of breast angiolipoma is associated with malignancy.
Diagnostic imaging and histology of breast angiolipomas
Histologically, an infiltrating breast angiolipoma will usually appear as an unencapsulated (or very thin-walled) tumor of mature lipocytes with many 'islands' of angiomatous elements and a network of capillaries. Breast angiolipomas rarely exceed 2 cm in diameter. Mammographically, there is really no typical appearance of breast angiolipomas. Somtimes nothing at all is seen, or possibly just a focal area of increased density, and sometimes a nodule. The close-up X-ray image of a breast angiolipomas shown above could be described as an irregular, ill-defined mass. But overall breast angiolipomas well tend to be well-circumscribed nodular densities, and may also present with irregular margins on mammography. The ultrasound presentation of a breast angiolipoma tends to be of a well-circumscribed, hyperechoic mass without posterior acoustic enhancement.
Treatment and management of vascular breast lesions
Almost all vascular breast lesions need some kind of excisional
biopsy to diagnose the benign nature of the tumor and to differentiated from
breast cancer or angiosarcoma. Most hemangiomas will disappear on their own
without treatment, however complete surigical excision is usually recommended
for a breast hemangiomas anyways, just to exclude the possibility of an underlying
angiosarcoma. Breast angiolipomas are also usually removed by simple surgical
excision, but where they are of the 'infiltrative' variety, a wider surgical
excision is usually undertaken to help prevent recurrence. If a wide surgical
excision is not possible, radition therapy is sometimes additionally used.
As breast angiolipomas can also be quite painful, treatment by surgical excision
is also necessary to relieve symptoms. Because breast angiolipomas have a
tendency to infiltrate through surrounding muscle layers, they can be difficult
and even dangerous to adequately resect. Treatment by transcatheter embolization
might be a reasonable alternative.
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Copyright Steven B. Halls, MD Last edited 15-August-2011