A deceptive fungating breast mass: giant fibroadenoma with multiple epidermal inclusion cysts mimicking malignancy.

AIMS: To describe a giant ulcerating fibroadenoma mimicking malignancy and highlight diagnostic uncertainty from discordant clinical, imaging, and biopsy findings.

PATIENTS AND

METHODS

A 22-year-old woman presented with an approximately 10 cm fungating, ulcerated right-breast mass complicated by methicillin-resistant Staphylococcus aureus infection. Multiple core biopsies showed fibroadenoma, despite rapid progression raising concern for phyllodes tumor or malignancy. Multidisciplinary review supported a staged breast-preserving approach.

RESULTS

The mass was enucleated with preservation of the nipple-areolar complex. Histopathology confirmed giant fibroadenoma with multiple epidermal inclusion cysts, cyst rupture, keratin-associated inflammation, and a foreign-body giant-cell reaction. Earlier biopsy material showed an epidermal component before clinical deterioration. Biopsy-related disruption of this preexisting component, together with inflammation, infection, cyst rupture, and wound breakdown, was considered a possible contributor to the fungating presentation; the exact sequence was uncertain. Histology showed focal superficial-margin involvement at the ulcerated/fungating surface. At six months, there was no clinical or ultrasonographic evidence of recurrence.

CONCLUSIONS

Giant fibroadenomas may mimic phyllodes tumor or breast malignancy. Clinicoradiological-pathological correlation and multidisciplinary planning can support breast-preserving management despite an alarming presentation when tissue diagnosis remains benign.