The Peculiar Leafy Giant: Giant Malignant Phyllodes Tumor With Axillary Lymph Node Metastasis

Abstract

Background: Malignant phyllodes tumors (MPT) are uncommon fibroepithelial breast neoplasms that usually disseminate hematogenously. Regional nodal involvement is exceptionally rare. We report an extreme presentation of a giant MPT with synchronous axillary metastasis and early systemic relapse, highlighting diagnostic pitfalls and therapeutic dilemmas.

Case presentation: A 44-year-old nulliparous woman presented with a rapidly enlarging 35 × 25 cm right-breast mass three years after excision of a borderline phyllodes tumor. Examination revealed peau d’orange, nipple retraction and a palpable 2 cm level-I axillary node. Core biopsy suggested MPT. Staging computed-tomography showed no distant disease. She underwent right modified radical mastectomy with level I–II axillary clearance. The 4.5 kg specimen measured 43.5 × 36 × 12.5 cm. Histology showed marked stromal overgrowth, 14–16 mitoses/10 HPF, lymphovascular invasion and six metastatic axillary nodes (pT4 N1 M0). Adjuvant chest-wall radiotherapy was recommended; however, ^18F-FDG PET performed at four months detected pulmonary metastases and a chest-wall implant. The patient defaulted systemic therapy and was lost to follow-up.

Conclusion: Giant MPT can breach traditional dogma by acquiring lymphatic spread. Axillary intervention should be contemplated when nodes are clinically abnormal. Given the poor post-metastatic survival, early referral to a sarcoma multidisciplinary team and enrolment in clinical trials are advisable.