A case of phyllodes tumor with rapid growth during pregnancy and lactation period: a case report

• Published in: Surgical case reports 2024-04, Vol.10 (1), p.98-98, Article 98
• Main Authors: Tohyama, Shiori, Horimoto, Yoshiya, Ushiyama, Yumiko, Semba, Ryoko, Hotchi, Shiori, Sugano, Naomi, Ogura, Kanako, Murakami, Fumi
• Format: Article
• Language: English
• Subjects: Breastfeeding & lactation; Case Report; Case reports; Medicine; Medicine & Public Health; Pregnancy; Surgery
• ISSN: 2198-7793; 2198-7793
• DOI: 10.1186/s40792-024-01895-w

Background The age of onset of the phyllodes tumor is generally in the late 40 s, and diagnosis and treatment during pregnancy and lactation are rare. We herein present a case of a phyllodes tumor that rapidly increased in size during the pregnancy and lactation period. Case presentation A 39-year-old woman was referred to our hospital with a mass in the right breast that increased in size during the pregnancy and lactation period. On ultrasound (5 week postpartum), a well-defined lobulated mass with internal septations and fluid retention was observed. Magnetic resonance imaging of the breast at 8 week postpartum revealed a 70-mm-sized smooth-margin mass with multilocular cystic components. Marked proliferation of stromal cells with high cell density was observed in a biopsy specimen taken at the previous hospital. We diagnosed the mass as a phyllodes tumor of borderline malignancy and excised it at 13 week postpartum. The excised tumor was 85 mm in diameter and its interior was filled with a milk-like substance. Histologically, there was only a mild increase in stromal cell density but fibrosis with associated degeneration was prominent. The final diagnosis was benign phyllodes tumor with degeneration. Conclusions We report a case of a phyllodes tumor that rapidly increased in size during pregnancy and the lactation period. The accumulation of a milk-like substance was thought to be responsible for the rapid growth of the tumor.