Teaching Case

A five-year-old child was referred to our breast unit with a right-sided, painless, palpable mass. This mass presented and increased in size for four months. On clinical examination, there was a nodular, non-tender lump in the subareolar region of her right breast. She had no history of trauma.

Bilateral breast ultrasonography was performed to clarify a right retro areolar mass. Ultrasonography showed a microlobulated, hypoechoic, solid lesion with arterial and venous vascularity in the Doppler study (figure 1, 2). The lesion was measured at 30x21 mm. There were a visible asymmetry between both breasts and mild bluish skin changes (figure 3, 4). There was no nipple discharge. It was classified as a BIRADS 4a lesion due to an increased size. No additional lesions and no susceptible lymphadenopathy were found. She has second-degree relatives with a history of breast cancer. A Tru-cut biopsy was performed under sonographic guidance.

Secretory carcinoma is children's most common type of primer breast malignancy. It is a rare tumour that accounts for < 0,1 % of all breast cancers. Firstly, it was termed in 1966 juvenile breast carcinoma by McDivitt and Stewart because of its presentation in children and adolescents [1]. Then, the name was changed to "secretory breast carcinoma" by Tavassoli and Norris since it has significant prominent secretory parts and affects all age groups [2].

Secretory breast carcinoma frequently presents as a palpable breast mass that is slow-growing, painless, mobile, and well-circumscribed. These features simulate fibroadenoma. A painless, enlarging, and firm mass should raise the suspicion of neoplastic lesions. In addition, bloody nipple discharge may be associated with secretory breast carcinoma. This lesion's location is usually in the subareolar area, but it can occur in any part of the breast [2, 3].

The differential diagnosis of breast lesions in the pediatric age includes a broad spectrum. Children's most frequent breast diseases are developmental abnormalities and benign solid masses (e.g, fibroadenoma). Malign breast lesions are generally metastases, and primary breast malignancy is extremely rare [4].

The appropriate first imaging modality is ultrasonography to evaluate breast lesions in children. Mammography is not routinely performed in the pediatric age group, although it is the routine modality of breast imaging in the adult population. The main reason is the high sensitivity of the developing breast to radiation exposure. In addition, increased fibroglandular tissue density can limit the sensitivity of mammography. When sonography revealed a suspicious malignant lesion, mammography could be considered following the ultrasound [4].

On mammography images, secretory breast cancer demonstrates by iso/hyperdense, round, or oval-shaped lesions. Focal architectural distortion and microcalcifications are not characteristic features. Sonographically, secretory carcinoma is shown as a well-marginated or particularly microlobulated, hypoechoic, oval, or round-shaped, solid lesion. Sometimes, this lesion could be associated with ductal ectasia and seen as intraductal papillary lesions on sonography [3].

Secretory breast cancer has a slow-growing pattern and favorable prognosis. Distant metastases are extremely rare. Metastatic infiltration of axillary lymph nodes is not frequent. Nodal metastasis is very unusual in tumours smaller than 2 cm. The tumour size is associated with lymph node invasion and recurrence [2]. The biopsy is necessary for a definitive diagnosis because of its nonspecific imaging features. After histopathologic confirmation of the lesion, surgical excision is the most appropriate treatment. The role of adjuvant chemotherapy and radiotherapy is unclear [5].

On our patient, histopathological analysis revealed the diagnosis of secretory breast carcinoma. Afterwards, wide surgical excision and biopsy of sentinel lymph nodes were performed. Sentinel lymph nodes are found to be negative for metastases. The final pathology was concordant with the diagnosis of secretory breast cancer.

The imaging features of secretory carcinoma are nonspecific and can mimic benign lesions. Therefore, secretory breast carcinoma should be kept in mind when making a differential diagnosis of the growing solid breast lesions in children.

Written informed patient consent for publication has been obtained.