Syringomatous adenoma of the nipple: A case series and systematic review.

Key Clinical Message: SAN should be considered in the setting of nipple discharge or morphology changes with typical histological findings. There are limited published cases of SAN, and workup of this pathology is still not clear to date. Abstract: Syringomatous adenoma of the nipple (SAN) is known to be a rare benign breast neoplasm. With a few cases documented in the literature, preoperatively diagnosing this tumor is a challenge, which often leads to invasive procedure such as mass excision with nipple removal. This study was aimed at presenting a case report of SAN and to conduct a review of published cases. Literature search was conducted through PubMed databases. Articles published from year 1983 to March of 2022 were included. Only histologically confirmed cases of SAN were included. The review was performed according to the PRISMA guidelines. Twenty-eight cases, including the newly reported case, were included in the review after going through inclusion criteria. The mean age at diagnosis was 44 ± 16 years. 7% were male. The most common presentation was palpable mass. Preoperative biopsy was done for 9 cases, out of which 7 did not indicate typical histopathological characteristic of SAN. Most common treatment was wide local excision with nipple removal. Immunohistochemical staining of the resected tumor was performed in 16 cases postoperatively. 32.1% (9/28) utilized p63 in constellation with histologic findings. Five cases that utilized staining also used Estrogen Receptor (ER) marker, while three used progesterone receptor (PR) marker. SAN should be considered in the setting of nipple discharge or morphology changes with typical histological findings. There are limited published cases of SAN, and workup of this pathology is still not clear to date. The case presented here and our comprehensive literature review suggest that pathohistological findings of SAN can be heterogeneous. Clinicians would also benefit from recognizing these variances. Further research and reported cases are needed to confidently diagnose SAN, which may open doors for less aggressive surgical treatment or surveillance option for asymptomatic patients.