Radiation-associated angiosarcoma of the breast with initial presentation as non-mass enhancement on MRI

Abstract

Radiation-associated angiosarcoma of the breast (RAASB) is a rare and aggressive malignancy occurring after radiation therapy as part of breast cancer treatment. RAASB usually presents several years after prior radiation and typically involves the skin with or without involvement of the parenchyma. Most RAASB are detected as cutaneous changes on physical exam. Herein, we present a unique case of a clinically occult RAASB diagnosed as non-mass enhancement on annual surveillance breast MRI.

Keywords: Angiosarcoma; Breast imaging; MRI; Sarcoma; Ultrasound; Women's imaging.

Fig. 1(A)

T2-weighted image demonstrates segmental increased signal in the right breast (straight arrow) and right breast skin thickening (curved arrow). (B and C) T1-weighted postcontrast subtraction images demonstrate segmental non-mass enhancement in the right breast (straight arrows) and mild background parenchymal enhancement in the left breast. (D) Maximum intensity projection (MIP) image of tissue contrast kinetics demonstrates segmental non-mass enhancement with washout kinetics (red color) in the right breast (straight arrow) as well as background parenchymal enhancement in the left breast. Incidentally noted fibroadenoma of the left breast (circle) was unchanged since initial MRI.

Fig. 2

Right craniocaudal (RCC) and right mediolateral oblique (RMLO) views demonstrate benign calcifications and stable post surgical changes of the lumpectomy site 2 years prior (A and C) and at the time of diagnosis (B and D).

Fig. 3(A)

Gray-scale ultrasound images with Doppler demonstrate two irregular hypoechoic right breast masses with peripheral vascularity noted at the 10-o'clock (A) and 11-o'clock (B) positions. Note the mild skin thickening (double arrow).

Fig. 4(A)

Maximum intensity projection (MIP) image from an FDG PET/CT exam demonstrates two FDG avid masses in the right breast (circle). (B and C) Axial fused FDG PET/CT images demonstrate a superior FDG avid mass with SUVmax of 4.4 (arrow), and a second, more inferior mass with SUVmax of 5.4 (arrow).

Fig. 5

Gross pathologic image of the right breast simple mastectomy specimen. There is an angiosarcoma forming an 8.3 × 5.8 × 4.5 cm mass in the central portion of the breast. The tumor does not involve the skin (dermis or epidermis). The closest soft tissue margin is deep and negative by 2.2 cm. The closest peripheral skin margin is inferior and negative by 2.5 cm.

Fig. 6(A)

Postirradiation angiosarcoma of the mammary parenchyma, growing in a diffusely infiltrative fashion between non-neoplastic ducts, lobules, and thick-walled blood vessels (H+E, ×100). (B) Higher power view of high-grade mammary angiosarcoma, showing both small fascicles of hyperchromatic spindled endothelial cells and formation of irregular, slit-like vascular channels lined by protuberant, hyperchromatic endothelia (H+E, ×200).