Subcutaneous Cavernous and Capillary Hemangiomas of the Breast: Radiologic-Pathological Correlation

Benign hemangiomas of the breast are rare. The mammographic and sonographic appearance of breast hemangiomas have been described in several reports (1-4) but only a few reports have included magnetic resonance imaging (MRI) or positron emission tomography/computed tomography (PET/CT) findings (5, 6). The mammographic features of hemangiomas have been reported as well-circumscribed or microlobulated lesions that may contain calcification (7). The reported sonographic appearance of hemangiomas is a superficial, well-defined, solid lesion with or without calcification. The echogenicity of hemangiomas varies and is mainly hypoechoic (1). PET/CT usually shows the absence of or low ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) uptake (5). We report two cases of breast subcutaneous hemangiomas, one of which were a cavernous hemangioma and was two capillary hemangiomas in a breast.

Hemangiomas are a rarely reported benign vascular tumor of the breast. Localized hemangiomas are classified into four groups by their origin: perilobular hemangiomas, parenchymal hemangiomas, subcutaneous hemangiomas, and venous hemangiomas (7). Hemangiomas are classified as capillary or cavernous hemangiomas by the size of their vascular channels. Cavernous hemangiomas are the most common type of breast hemangioma. In contrast to cavernous hemangiomas, capillary hemangiomas are relatively rare (8). Capillary hemangiomas of the breast are relatively rare and they are usually clinically unapparent, whereas cavernous hemangiomas may reach a size where they can be palpated (8). Mesurolle et al. (1) reported only two cases of capillary hemangioma and 14 cavernous hemangiomas among 16 cases in their study. Two case reports of cavernous hemangioma are available in the Journal of the Korean Radiological Society (3, 4). These reports present subcutaneous cavernous hemangiomas with mammography, sonography, and MRI findings. However, no reports have included a biopsy-proven capillary hemangioma with PET/CT findings. It is very important to establish the exact diagnosis of cavernous and capillary hemangiomas, which require a differential diagnosis from angiosarcoma (8, 9).

Cavernous hemangiomas are composed of multiple large dilated blood-filled vessels with a shared common wall. The vessels are supported by fibrous stroma. Small capillary-dimension vessels may be seen in portions of a cavernous hemangioma. In many cavernous hemangiomas, vascular channels drift into the fatty parenchyma becoming small at the periphery, which duplicates the histological appearance of peripheral parts of an angiosarcoma (9). In contrast to the cavernous type, capillary hemangiomas are composed of small, capillary-sized vascular channels lined by endothelial cells. Fibrous bands, which subdivide lesions, are variably present. Large, muscular vessels may be present within and at the periphery of the tumor.

The mammographic features of hemangiomas are nonspecific. It has been reported as well-circumscribed or microlobulated lesions that may contain calcification (7). Hemangiomas are often located superficially either subdermally or within the subcutaneous tissue so the tangential view can be useful. In our cases, a cavernous hemangioma appeared as a microlobulated oval isodense nodule, and the capillary hemangiomas appeared as partly obscured oval hyperdense nodules.

No reports are available on sonographic criteria to distinguish the two types of breast hemangiomas. The sonographic appearance of hemangiomas has been reported as superficial, well-circumscribed, solid masses consistent with benign lesions (2). Microlobulations or indistinct margins are less often observed. The echotexture of hemangiomas varies but is mainly hypoechoic. In our cases, a cavernous hemangioma appeared as a subcutaneous circumscribed oval hypoechoic nodule and the capillary hemangiomas appeared as partly indistinct or circumscribed oval mixed isoechoic or hyperechoic nodules. Mesurolle et al. (1) reported only one case of isoechoic lesion among nine breast hemangiomas with sonographic findings in their study. Other cases included two hypoechoic, three hyperechoic, and three complex echo patterns. Isoechoic echogenicity likely accounts for the difficulty in identifying hemangiomas against a fatty background. This may explain the relatively small percentage of isoechoic hemangiomas detected by ultrasound in previous studies (1). In these cases, the exact localization of the mass may help the radiologist identify lesions and make a correct diagnosis. A primary breast mass can be excluded when the mass is definitely located anterior to the anterior layer of the superficial pectoralis fascia (2). Differential diagnoses of the subcutaneous mass include hematoma, lipoma, sebaceous cyst, and hemangioma on sonography. A breast hematoma demonstrates avascular complicated or complex cystic mass and is often fluid-fluid. History of trauma or previous intervention is vital. The lipoma and benign fat-containing lesions show a typical radiolucent circumscribed mass on mammography (10). The fat-fluid level on lateral view may be seen. A sebaceous cyst typically involves the dermis, and dermal layer involvement should be carefully investigated (2). Most common sites include areas of redundant skin folds such as the inframammary fold, parasternal, and axilla.

Breast hemangiomas present either absent or low FDG uptake on PET/CT. However, a case of hemangioma with increased ¹⁸F-FDG uptake (simulating malignancy) has also been reported. Blood retention in the hemangioma results in focal ischemia and may accelerate anaerobic glycolysis, leading to high FDG uptake (5). In our case 2, the two capillary hemangiomas did not show increased FDG uptake. One capillary hemangioma in the upper outer quadrant of the right breast appeared as a partly ill-defined oval isodense nodule on the nonfused CT image. The other palpable capillary hemangioma in the upper inner quadrant of the right breast was invisible on the nonfused CT image, although subcutaneous nodules could be easily demonstrated in surrounding fat tissue.

Contrary to previous studies, this palpable nodule was also invisible on mammography and CT. These atypical image findings of the capillary hemangioma in our case can be explained by correlations with pathologic and radiologic findings. The microscopic examination demonstrated an ill-defined infiltrative lesion between abundant adipose mimicking angiolipoma. Sonography also revealed a partly indistinct margin. This nodule might be difficult to distinguish from subcutaneous fat tissue on mammography and PET/CT because of its indistinct nature and large fatty component.

It is difficult to distinguish between the two types of breast hemangiomas using imaging findings. One study suggested that dynamic MRI may be helpful in the differential diagnosis. Hayasaka et al. (6) reported on the dynamic MRI appearance of a mixture of capillary and cavernous hemangiomas. They suggested that intensive enhancement in the early phase of gadolinium-enhanced dynamic imaging is consistent with the capillary type, and that the gradually enhanced portion is consistent with the cavernous type.

There is no difference in treatment between cavernous and capillary hemangiomas. When a breast hemangioma is confirmed histologically via core needle biopsy, complete excision is usually recommended (9). A core needle biopsy is insufficient because peripheral portions of a cavernous hemangioma may be indistinguishable from low-grade angiosarcoma in a small sample.

In conclusion, we describe two cases of cavernous and capillary hemangioma of the breast with radiologic-pathologic correlations. We expect that our image findings of breast hemangiomas will be beneficial for differentially diagnosing other similar breast lesions.