Giant juvenile fibroadenoma in an 11-year-old girl.

Clinical History

An 11-year-old girl was referred to our hospital due to a rapidly enlarging mass in the left breast. At physical examination, a palpable lump with prominent veins on the skin was noted (Fig. 1).

Imaging Findings

Ultrasound demonstrated a hypoechoic well-defined avascular mass replacing most of the left breast tissue. Axillary lymph nodes were not identified (Fig. 2 and 3).
Conventional MRI sequences were performed to define the precise size of the mass and to identify normal breast tissue. No contrast was administered. The mass was located in the lower inner quadrant of the left breast with the pectoralis muscle underlying the mass. It displaced the breast normal tissue superiorly and laterally. On T1-weighted images the mass was isointense and hyperintense on STIR T2-weighted images (Fig. 4 and 5). It measured 11x11x73 mm (APxTxCC).
Preoperative chest radiograph was taken and showed the mass in the left breast without evidence of bone involvement, pulmonary nodules or pleural effusion (Fig. 6).
Biopsy and subsequent excision of the lesion were performed by the surgeon. The initial biopsy diagnosis was juvenile hypertrophy, but the final histological diagnosis of the surgical specimen was giant fibroadenoma.

Discussion

Juvenile fibroadenoma is also named cellular fibroadenoma and it is an uncommon histologic variant of fibroadenoma. It constitutes 7 to 8% of all fibroadenomas and it is considered giant if it measures over 5 cm. Juvenile fibroadenoma is more common in African American adolescents [1, 2].

It is usually multilobulated or bosselated and some of them may have a cleft-like shape. It is histologically distinguished by a hypercellular stromal proliferation with canalicular or pericanalicular patterns [1]. If there are mitoses in the sample, they are usually few and confined to the stroma around the epithelial-line clefts [1].

Juvenile fibroadenomas are rapid-growing tumours that can replace or compress the normal breast tissue [2]. Patients present a rapidly enlarging mass that may be associated with skin ulcerations and prominent veins. The mean age of presentation is between 11 and 18 years [3].

Ultrasound is very sensitive in the detection of fibroadenomas. It is the most suitable imaging technique in detecting masses in fibroglandular breast tissue of young females. The typical imaging appearance of a fibroadenoma in ultrasound is a well-defined oval mass with uniform hypoechogenicity. It is usually avascular or may present some central vascularity [1].

At MR imaging, fibroadenomas may have variable appearance and they cannot be differentiated from phyllodes tumour. In our case, we performed an MRI in order to define the exact size of the mass, identify the normal breast tissue, and plan the surgery.

As juvenile fibroadenomas are usually large and rapid-growing tumours, excision of the lesion is the treatment of choice. Due to its size, reconstructive techniques and practical surgical expertise are usually required. It is important to preserve the normal breast parenchyma, adjust the skin envelope, get a symmetrical position of the nipple-areola complex bilaterally, and avoid iatrogenic amastia via excision of the breast bud in children [3].

Juvenile fibroadenoma should be considered in the differential diagnosis of a rapidly enlarging breast mass. Fibroadenoma is usually difficult to differentiate from phyllodes tumour because imaging findings may overlap. Therefore, tissue sampling is required. Although juvenile fibroadenoma and juvenile hypertrophy may present rapid breast enlargement, juvenile hypertrophy tends to be bilateral [1]. On the other hand, primary breast sarcoma is a very rare and aggressive tumour. It constitutes less than 1% of all breast cancers [4]. Even though it is also a rapid enlarging breast mass, malignancy is uncommon in adolescents [2].

Differential Diagnosis List

Final Diagnosis

Juvenile fibroadenoma

URL:	https://www.eurorad.org/case/14013
DOI:	10.1594/EURORAD/CASE.14013
ISSN:	1563-4086