Rare breast cancer subtype that recurred years later in a more aggressive form

What happened, in summary

A woman in her 60s had first been treated for a small T1 adenoid cystic carcinoma of the left breast approximately 12 years earlier. Initial lumpectomy left positive margins, so she later underwent mastectomy with axillary dissection. No residual tumour was found in the mastectomy specimen. Because tissue was unavailable to establish hormone-receptor status, she received tamoxifen empirically for 5 years and continued follow-up for several years before being lost to surveillance.

About 11–12 years after the original diagnosis, she developed a new lump along the outer end of the left chest-wall surgical scar. It had been present for 1 year and had become painful over the preceding 2 weeks. The mass measured approximately 5 × 5 cm and was firm, irregular, warm and tender, with reddened overlying skin. Evaluation showed recurrent adenoid cystic carcinoma with high-grade transformation, a rare and more aggressive change. The transformed component was focally positive for CD117 and had a high proliferative index.

Her case was reviewed by a multidisciplinary team. At that point, no distant metastases were identified. The recurrent lesion was managed surgically, followed by radiation of 50 Gy in 25 fractions over 5 weeks. Chemotherapy was not given because of the long disease-free interval, lack of detectable distant spread at that time and her preference to avoid it.

She tolerated radiation, but CT 1 year later showed another local recurrence and metastatic nodules in both lungs. She then chose to continue treatment at another centre. Her journey demonstrates that breast adenoid cystic carcinoma can recur more than a decade after initial surgery and may become biologically more aggressive over time.