Perilobular Capillary Hemangioma

Angiolipoma

Age

Middle age or older women

Any age

Location

Anywhere in the breast

Breast subcutaneous tissue, rarely mammary parenchyma

Presentation

Incidental finding

Painful dermal nodules, may be multiple

Imaging findings

None or small nodular density

None or rarely nodular density

Etiology

Unknown

Unknown

Histology

1. 
   

   Well-circumscribed proliferation of thin-walled capillaries that may involve the intralobular or extralobular stroma (Fig. 10.1.1)

   
   
2. 
   

   Incorporates lobular unit(s) but does not invade epithelial structures (Figs. 10.1.2, 10.1.3, 10.1.4)

   
   
3. 
   

   Capillaries are lined by attenuated endothelial cells with small nuclei devoid of atypia (Fig. 10.1.5)

1. 
   

   Well-circumscribed lesion composed of an admixture of mature adipose tissue and noninfiltrative small vascular spaces (Figs. 10.1.6 and 10.1.7)

   
   
2. 
   

   Vascular spaces may be compressed and slit-like (Fig. 10.1.8)

   
   
3. 
   

   Adipose tissue is an integral component of the lesion (Fig. 10.1.9)

   
   
4. 
   

   Vascular spaces lined by bland endothelial cells containing intravascular hyaline microthrombi (Fig. 10.1.10)

Special studies

None

None

Treatment

None, excision unnecessary

None, excision not required unless painful

Clinical implication

None, benign incidental finding

None

Perilobular Capillary Hemangioma

Atypical Vascular Lesion

Age

Middle age or older women

Middle age and older women, (usually sixth decade)

Location

Anywhere in the breast

Breast skin

Presentation

Incidental finding

Papules or plaques appearing several years (average 3-4 y) following radiation therapy; red-brown or pink

Imaging findings

None, rarely nodular density

May show skin thickening

Etiology

Unknown

Radiation exposure, often for breast cancer

Histology

1. 
   

   Well-circumscribed proliferation of thin-walled capillaries that may involve the intralobular or extralobular stroma (Figs. 10.2.1, 10.2.2, 10.2.3)

   
   
2. 
   

   Incorporate lobular unit(s) but do not invade epithelial structures (Figs. 10.2.1, 10.2.2, 10.2.3, 10.2.4)

   
   
3. 
   

   Capillaries are lined by attenuated endothelial cells with small nuclei devoid of atypia (Fig. 10.2.5)

1. 
   

   Localized, often wedge-shaped collection of haphazardly arranged and focally dilated vascular spaces in dermis. May be very subtle (Figs. 10.2.6 and 10.2.7)

   
   
2. 
   

   Vascular spaces may have a complex branching pattern and may be anastomosing (Fig. 10.2.8)

   
   
3. 
   

   The vascular spaces are confined to the dermis and lined by single layer of plump endothelial cells with nuclear hobnailing and hyperchromasia, but no mitoses (Fig. 10.2.9)

   
   
4. 
   

   Vessels suggest an infiltrative process; however, overall small size and circumscription support a diagnosis of atypical vascular lesion (Fig. 10.2.7)

Special studies

None

None to distinguish from capillary hemangioma

Treatment

None, excision unnecessary

Atypical vascular lesions should be excised with the aim of obtaining negative margins

Clinical implication

None, benign incidental finding

Following complete excision, the majority pursue a benign clinical course with a few cases reportedly recurring locally or progressing to angiosarcoma

Atypical Vascular Lesion

Postradiation Angiosarcoma, Low-Grade Histology

Age

Middle age and older women (usually sixth decade)

Women over 50 y of age (approximately 20 y older than women with primary angiosarcoma), time to diagnosis ranges from 2.5 to 11.5 y (median 4.5 y) after radiation therapy; risk of developing postradiation angiosaroma is approximately 0.3%

Location

Breast skin

Breast skin, may extend into adjacent mammary parenchyma

Presentation

Papules or plaques appearing several years (average 3-4 y) following radiation therapy; red-brown or pink

Multifocal, cutaneous, purple-blue and erythematous plaques, papules, or nodules within the radiation field which may secondarily involve adjacent breast parenchyma

Imaging findings

Skin thickening; none

None or skin thickening; associated ill-defined density with involvement of breast parenchyma; magnetic resonance imaging (MRI) may be useful in defining the size

Etiology

Radiation exposure, usually for breast cancer

Radiation treatment for breast cancer

Histology

1. 
   

   Localized, often wedge-shaped collection of haphazardly arranged and focally dilated vascular spaces in dermis. May be very subtle (Fig. 10.3.1)

   
   
2. 
   

   Vascular spaces may have a complex branching pattern and be anastomosing (Figs. 10.3.2 and 10.3.3)

   
   
3. 
   

   The vascular spaces are confined to the dermis and lined by a single layer of plump endothelial cells with nuclear hobnailing and hyperchromasia, but no mitoses (Fig. 10.3.4)

   
   
4. 
   

   Vascular spaces separated by small bundles of dermal collagen

   
   
5. 
   

   Vessels suggest an infiltrative process; however, overall small size and circumscription support a diagnosis of atypical vascular lesion

1. 
   

   Complex, anastomosing vascular channels that infiltrate the dermis and/or the breast parenchyma (Figs. 10.3.5 and 10.3.6)

   
   
2. 
   

   Well-defined vascular spaces lined by cells with prominent nuclei that protrude into the vascular lumen (Figs. 10.3.7 and 10.3.8)

   
   
3. 
   

   Subtle permeation of adipose tissue mimics angiolipoma

   
   
4. 
   

   May contain atypical vascular lesion-like areas in the periphery of the lesion; distinction from atypical vascular lesion on core biopsy specimen may be difficult, requiring excision for diagnosis

Special studies

Absent c-myc expression by immunohistochemistry and lack of myc amplification by fluorescence in situ hybridization (FISH) distinguish from angiosarcoma with high specificity; immunohistochemistry for ERG may reassure a limited extent of the process and circumscription but does not distinguish from angiosarcoma. Immunohistochemical staining for vascular markers does not distinguish from angiosarcoma.

MYC amplification present in >50% of postradiation angiosarcomas but absent in atypical vascular lesions. Immunohistochemistry for c-myc shows nearly 100% concordance with MYC amplification as detected by FISH. Immunohistochemical expression of vascular markers does not distinguish from atypical vascular lesions.

Treatment

Atypical vascular lesions should be excised with the aim of obtaining negative margins. When diagnosed on needle core biopsy, excision is generally warranted to exclude angiosarcoma.

Total mastectomy; wide excision alone is associated with high recurrence rates. Radiotherapy and chemotherapy ineffective.

Clinical implication

Following complete excision, the majority pursue a benign clinical course with a few cases reportedly recurring locally or progressing to angiosarcoma. Distinction from angiosarcoma is critical to avoid excessive surgery and inappropriate prognostication.

Postradiation angiosarcoma, regardless of grade, has a poor prognosis with a mean survival of 1-2 y