Arteriovenous malformation (AVM) is an abnormal anatomical characteristic of vessels where a larger number of dilated inflows and outflows of vessels are seen, which extend to other surrounding tissue layers. 1 Breast AVMs are slow flow malformations (Feeding artery and Draining vein) that can be diagnosed with the help of ultrasound, color Doppler, dynamic contrast-enhanced MRI, and also X-ray Mammogram, depending on the age of the patient to look for calcifications. 2 An early diagnosis of AVMs can be treated with sclerotherapy or ablative techniques, or surgery. 3

A female patient in her early 20s presented to the hospital with discoloration and swelling near the neck and chin region. The patient underwent an MRI (Figure 1 A, B, C) of the face which revealed venous malformation for which the patient underwent sclerotherapy (Figure 1 D, E, F). Before her one-year follow-up visit for previously treated head and neck AVM, she had an incidentally discovered bluish-red discoloration in the upper inner quadrant of her left breast.

On clinical examination, a compressible 2x2cm swelling in the upper inner quadrant of the left breast with mild warmth was present. The swelling was soft in consistency with no tenderness and blanched on pressure. Clinical examination of previously treated sites of AVM was done which revealed no further abnormality at the treated site.

Ultrasound of the left breast showed an oval circumscribed hypoechoic mass with gentle lobulations with significant internal vascularity (Figure 2A, B) in the left breast at the 10 o'clock position in circle 2, beneath the superficial skin discoloration. On colour doppler, the venous flow was noted within the lesion and a small artery was noted at the periphery of the lesion ( Figure 2C). The ultrasound of the right breast was unremarkable.

Dynamic contrast-enhanced MRI of both breasts was advised which showed an irregular T1 iso and T2 hyperintense mass with micro-lobulated margins in To confirm the presence of calcifications within the mass, an x-ray mammogram was done which showed an irregular circumscribed high-density mass in the upper inner quadrant of the left breast with few punctate and round calcifications within -indicative of phleboliths (Figure 4 A, B).

Chest wall lesions can mimic masses on mammograms and can cause diagnostic difficulty in interpretation. Vascular chest wall lesions are extremely uncommon, of which venous malformations (VM) are the most common type of congenital malformation with an estimated incidence of 1%, arising due to abnormal vasculogenesis or angiogenesis. 4 When large enough, they may project into the overlying breast tissue and be visible on mammograms causing a diagnostic dilemma. The differential diagnosis of these kinds of symptoms may be atherosclerosis, superficial thrombophlebitis, Varix, venous collaterals, Psudoangiomatous stromal hyperplasia (PASH), symmetric in congestive heart failure, Osler-weber syndrome fibroadenoma, complex cyst, hemangioma, Lymphangioma, Angiolipoma, Angiosarcoma, and Hemangiopericytoma. 567 Usually, biopsy is not recommended in this kind of case. In AVM, there is an involvement of arteries and veins, rather than the lesion or mass. Profuse bleeding may occur if a biopsy is attempted and left undisturbed, with most of the AVMs remaining stable.

Risk factors in causation and association of cancer: Rare cases of malignant degeneration into squamous cell carcinoma, 8 in a long-standing lesion and lymphangiosarcoma 9 at the site of irradiated lymphangioma circumscriptum have been reported. Although these tumors are rare, the breast is one of the more common locations in which they occur. 10

Breast venous malformations are benign vascular malformations of breast tissue and are slow-flow venous malformations (nomenclature according to ISSV classification). 2 They are mostly incidentally found and patients do not have any symptoms except for cosmetic reasons at times. Very rarely postsurgical venous malformations are also seen. The venous malformations that occur within the breast are mostly cavernous type, hence similar to cavernous hemangiomas occurring elsewhere in the body, 11 and these appear as a lobulated cluster of non-neoplastic vessels filled with slow-moving blood. 12 No predilection is seen for any side of the breast or quadrant.

X-Ray Mammogram -malformations are usually seen as oval circumscribed equal or high-density masses with benign calcifications (phleboliths); Ultrasound of the breast -malformations usually appear as parallel oriented predominantly hypoechoic masses with vascularity and few calcifications. These masses are mostly superficial with overlying skin discoloration. Dynamic contrast-enhanced MRI of the breasts appears hypointense on T1 and T2 with flow voids in T2 and shows early enhancement and slow washout on post-contrast images. These masses often have type 2 or type 3 kinetic curves. 13

When a patient presents with a new lesion suggesting suspicious MR curves, the preference is to exclude malignancy. It should be noted that both may have similar imaging characteristics and that AVM is one of the lesions which results in a false positive diagnosis of malignancy. It is also important to note that both morphology and kinetic curves should be considered in the grading of a lesion on MR (alongside other available imaging). It has been shown that suspicious morphology offers a higher yield than a suspicious kinetic curve. If an imaging modality like mammography, ultrasound, or MR increases the suspicion of a malignant lesion, a tissue diagnosis is then essential to exclude it. If a lesion cannot be localized on a second-look ultrasound, an MR biopsy is the next appropriate course to obtain a tissue diagnosis.

The patient provided written informed consent to publish the information and images contained in the case report.