Sclerosing Lymphocytic Lobulitis Mimicking a Tumor Relapse in a Young Woman with a History of Breast Cancer

Case report We present the case of a 27-year-old woman who was referred to our hospital for further investigation, after worrying findings during a routine check-up performed in another hospital. Five years prior to this check-up, the patient was diagnosed with cancer of the left breast at the very young age of 22. The tumor was staged as pT2N0M0, with the histologic examination showing a poorly differentiated invasive ductal adenocarcinoma with strong estrogen and progesterone receptor expression and negative herceptin status. The treatment consisted of a wide excision and sentinel node procedure, followed by adjuvant chemotherapy, radiotherapy and hormonal therapy. Because of her young age, 3 cycles of cyclophosphamideepirubicin-fluorouracil (FEC) and 3 cycles of docetaxel were given. Chemotherapy was followed by radiotherapy of the left breast up to a dose of 50 Gy, with a boost of 16 Gy on the tumor bed. Hormonal therapy consisted of a combination of tamoxifen and triptorelin. There was no relevant personal medical history, nor family history of breast cancer. Genetic analysis failed to show any BRCA1 or BRCA2 mutations. The patient recovered well and follow-up examinations were normal. At the time of the check-up, five years after surgery, coinciding with the conclusion of the hormonal therapy, the follow-up mammogram (Fig. 1A) and first ultrasound showed the surgery related changes. (Fig. 1A) Because of her young age, magnetic resonance imaging (MRI) of the breasts was also performed (examination performed on Siemens Magnetom Symphony 1.5T), showing a multifocal nodular contrast enhancement in the retroareolar region and the lower-outer quadrant of the right breast (Fig. 1B). These findings were not present on the previous MRI, performed two years after surgery. There were no clinical abnormalities in the region of this contrast enhancement. Because of the unclear etiology of these findings, the woman was referred to our department for further investigation. On ultrasonography, we were able to visualize some parenchymal distortion and an ill-defined hypoechoic lesion with a diameter around 1 cm and mild posterior acoustic shadowing in the region of the contrast enhancement on MRI (Fig. 1C). Because of the ultrasound and MRI findings and the patient’s history of breast cancer, the examinations were categorized as BIRADS 4. An ultrasound-assisted core biopsy (4 × 14 Gauge) was performed. Histologic examination showed a dense lymphocytic infiltrate of predominantly B-lymphocytes surrounding the ductulolobular unit and the vessels, in combination with a fibrous stroma of low cellularity and an increase in fibroblasts. These findings led to a diagnosis of sclerosing lymphocytic lobulitis. No signs of malignancy were detected. After diagnosis of sclerosing lymphocytic lobulitis, follow-up consisted of a breast ultrasound every six months and a yearly mammogram and MRI of the breasts. The volume of the hypoechoic lesion on ultrasonography and the intensity of the gradual multifocal contrast enhancement on MRI have both progressively diminished on consecutive examinations, to a level where it is barely perceptible (Fig. 2A and B). CASE REPORT