Primary breast aspergillosis mimicking breast malignancy – a rare case report

Fungal infections of the breast are very rare⁽¹⁾ except during lactation and in cases of immunodeficiency⁽²⁾ and are essentially not encountered in healthy subjects. Aspergillosis is an opportunistic infection which commonly involves the lungs. Extrapulmonary locations, such as the skin or breast, are rare^(2–4).

A 73-year-old female with plasmacytoma diagnosed 4 years earlier. She did not remember the names of medications, but she was still under medical control in a referential center.

The patient was under medical control due to plasmocytoma. The tumor of the breast occurred during the remission of plasmacytoma. She did not take any medications at that time.

Our patient was referred to the Clinic of Breast Disorders for the evaluation of a palpable mass in her left breast. The patient presented with ulceration and bloody, purulent discharge. Relevant medications included Clindamycin and steroids. Mammography of both breasts revealed adipose tissue with non-suspicious calcifications. The right breast without evidence of infiltrations. The left breast with a periareolar nodule measuring approximately 30 mm in diameter (BI-RADS 0). Ultrasonographic examination was ordered.

Ultrasound examination revealed a lesion (28 × 16 mm), with partially indistinct margin, (Fig. 1) predominantly solid with some fluid collection, isoechoic with acoustic shadow and peripheral vessels (Fig. 2) in the upper outer quadrant of the left breast. On elastogramme, the lesion was predominantly hard compared to the surrounding tissue^(1,2) (Fig. 3). The milk ducts were not dilated. There were no abnormalities observed in the axillary lymph nodes. Finally, based on the BIRADS-lexicon features⁽⁵⁾, the lesion was classified as BI-RADS 4b and subsequently fine needle aspiration (FNA) as well as core needle biopsy (CNB) were performed.

Fig. 1.

Fig. 2.

Fig. 3.

The CNB material is sufficient to make a diagnosis. It is a basis for the diagnosis of neoplastic changes in the breast. FNA has the advantage that an initial diagnosis can be made within hours.

Fine needle aspiration samples were preserved in alcohol and CNB samples were stored in formaldehyde and stained with Hematoxylin and Eosin. The material from FNA revealed stromal elements, ductal epithelial cells, chronic and subacute infiltrates and fragments of mycelial filaments in the connective tissue (Fig. 4).

Fig. 4.

CNB slides revealed characteristic Aspergillus filaments (Fig. 5). The findings were confirmed by the mycology lab.

Fig. 5.

Aspergillosis is an opportunistic infection, which leads to hyphae growth and invasion of the blood vessels, followed by necrosis and hemorrhage. In the presented case, the ultrasonographic and mammographic manifestation was highly suggestive of malignancy. In the differential diagnosis of the isoechoic lesion, we initially considered normoechoic neoplastic lesion (such as lobular breast cancer), fat necrosis, and inflammation. Skin infiltration is commonly seen in advanced cases of breast cancer.

Biopsy findings allowed for the diagnosis.

My review of medical literature indicates that fungal mastitis is very rare and may suggest immunodeficiency^(2,6). In our case the lesion was classified as BIRADS 4b and it was suspected to be a neoplasm. FNA and CNB revealed that it was Aspergillus infection rather than recurrence of extraskeletal plasmacytoma or primary carcinoma of the breast. There are literature reports describing such infections in patients with silicone mammary implants and in immunodeficient subjects⁽⁷⁾. In our case, the inflammatory (not neoplastic) lesion in FNA was richer in mycelial filaments.

In a study published by Kloska et al., the lesion presented differently in ultrasound examination and MMG⁽²⁾.

In ultrasound, the lesion had a thin distinct hypoechoic border, and a moderately hypoechoic center with irregular acoustic shadowing. On MMG, the lesion had no microcalcifications, and presented with lobulated and ill-defined margin.

In our case, the patient had previously immunosuppressive treatment due to plasmocytoma. There were inflammation and necrotic changes with bloody, purulent discharge in the skin over the tumor. The tumor was located in the breast, but the lesion which affected the skin did not recede after antibiotic therapy. In such situations, the diagnosis can be made based on biopsy.

FNA and CNB slides were diagnostic, but in case of inflammation FNA can be more helpful. Some authors recommend making parallel FNA and CNB to increase the sensitivity of preoperative diagnosis^(8,9).

For this reason, CNB is the gold standard in cases of moderate to high risk of malignancy in ultrasound and MMG examinations.

The clinical history of plasmocytoma should raise a suspicion of an opportunistic infection, which is common in immunocompromised patients. Breast biopsy allowed to make a diagnosis.