Pilonidal sinus of breast, a case report with literature review

INTRODUCTION: Pilonidal sinus (PNS) is an acquired inflammatory infection that mostly occurs in the sacrococcygeal region. This study aims to present a case of breast pilonidal sinus with a brief literature review. CASE PRESENTATION: A 31-year-old female presented with two painful right breast lumps for about one-month duration. Ultrasound (US) examination revealed heterogeneous areas with minimal inflammation at the right breast. There was also a nipple inversion, retro areolar duct dilatation, skin fistula, and reactive inflammatory level I axillary lymph nodes, suggesting inflammation/infection. Wide local excision was done. Histopathological examination revealed duct ectasia with a focus of sclerosing adenosis and a single hair shaft located in the breast tissue. DISCUSSION: Authors encourage surgical treatment (excision and primary closure) due to high recurrence risk after aspiration, medical treatment, and slow response of the abscess to antibiotic administration. Gender, family history, smoking, overweight, sinus size, poor hygiene, and surgical technique are among the risk factors that play a role in recurrence. CONCLUSION: Breast PNS is a very rare and atypical variant of PNS that may occur due to nipple inversion, hormonal effect, poor hygiene, tight brassieres. Surgical treatment is the best option to reduce recurrence risk.