We present a case of a 65-year-old woman who lives in rural areas presented with a 1.5×2cm mass in her left breast three months ago. Three months later, the mass increased to 3×3cm and she was admitted to the Sun Yat-sen University Cancer Center. The patient's spirit, appetite and sleep were normal since the discovery of the mass, and there was no significant change in body weight. On initial presentation, her vital signs were as follows: temperature 36.5°C, heart rate 82 beats/min, respiratory rate 18 breaths/min, blood pressure 143/84 mmHg, breathing is stable, lung breathing is clear, the chest was symmetrical, the breasts were symmetrical and there was no local uplift or depression, the skin was not redness, edema and orange skin changes, and the superficial veins of the breast were not dilated, both nipples are at the same level, no nipple invagination observed. Her initial laboratory tests demonstrated a white blood cell (WBC) count of 6.91× 109/L with normal eosinophils, a hemoglobin concentration of 126 g/L, and a platelet count of 296× 109/L.
A palpable mass was present 8cm from the nipple in the inner quadrant of the patient's left nipple, bout 3×3cm in size, with hard texture, uneven surface, unclear boundary and poor mobility. There was an enlarged lymph node palpable in the left axilla, about 1.5cm in diameter. Breast ultrasonography showed multiple bands with low echo and uneven echo (Fig. 1A). Color doppler flow imaging showed no blood flow signal in the lesion (Fig. 1B). Subsequently, a lumpectomy was carried out and revealed a 30 cm worm.
Histopathological examination of the worm showed tegmental layer, muscle fiber bundles, and the parenchymal tissue (Fig. 2A). Therefore, we diagnosed this case was sparganosis and the worm was Sparganum proliferum. To further verify our diagnosis, we used PCR to identify the cytochrome oxidase subunit 1 (COX1) gene of the worm. Briefly, the genomic DNA of the worm was extracted by HiPure Tissue DNA Mini Kit (Magen, China). The following protocol was conducted to amplify COX1 gene: 95˚C for 5 min, 35 cycles at 95˚C for 50 s, 52 for 50 s, and 72˚C for 50 s, with a final extension at 70˚C for 10 min. The primers were COX1 gene of Spirometra erinaceieuropaei: forward primer: 5′-TTTTTTGGGCATCCTGAGGTTTAT-3′; reverse primer: 5′- TAAAGAAAGAACATAATGAAAATG-3′. Fig. 2B shows the result of the PCR. Genetic sequencing was used to analyze PCR products. After homology searching with the Nucleotide BLAST in the National Center for Biotechnology Information (NCBI) database (http://blast.ncbi.nlm.nih.gov/Blast.cgi). The sequence exhibited 99% homology with Spirometra erinaceieuropaei COX1 gene (Sequence ID: KJ599680.1). The alignments displayed the following: score = 739 bits (400), expect = 0.0, identities = 408/411 (99%), gaps = 3/417 (0%), and strand = Plus/Minus. These data indicated that the worm was Sparganum proliferum.