Malignant phyllodes tumor

Case contributed by Yaïr Glick
Diagnosis certain


Left breast has been significantly enlarged for the past year, has become painful during the past few weeks.

Patient Data

Age: 35 years
Gender: Female

Right breast of normal sonographic echotexture. No mass demonstrated. Axilla normal.

Huge mass in left breast, demonstrating mixed echogenicity with cystic components. Internal flow not as elevated as with acute inflammation.

Left axilla normal.

The breast is a bit tender.

BI-RADS 4A - low level of suspicion for malignancy.

Trucut biopsy recommended.

Phyllodes tumor was suspected. Underwent incision and drainage of necrotic material from the tumor. Material sent for pathology:

Fragments of malignant phyllodes tumor, high grade. Wide areas of necrosis seen.
Immunostains: PAN- CK, ER, and PR positive in epithelial component. Vimentin, CKIT, CD34 (focally weakly), and P53 positive in stromal component. P63 negative.


CT chest-abdomen-pelvis for staging - only chest included here.

Mass measuring 14.5 x 12.4 x 14.7 cm (TRV x AP x CC) fills and expands the left breast. The mass shows extensive areas of necrosis and a small cluster of calcific foci (the latter are most probably calcifications seen on CT abdomen 2 years prior engulfed by the tumor). The mass cannot be visually separated from the left pectoralis muscles. Two adjacent tiny intratumoral air bubbles - most probably iatrogenic. Subcutaneous fat stranding in the chest wall posterior and inferior to the mass.

No radiographic evidence of chest adenopathy or abdominopelvic metastatic spread.

2.5 mm long polygonal subpleural nodule in the upper segment of the right lower lobe (RLL), most probably representing an intrapulmonary lymph node. Several tiny right middle lobe (RML) nodules with ground-glass halo - metastases? inflammatory nodules?

Underwent left mastectomy. Breast sent for pathology:

Malignant phylloides tumor, maximal diameter is 15 cm. Skin, nipple and resection margins are free. Minimal distance to inked margins is 0.25 mm. Lymphovascular invasion not seen.

P53 and C- kit (in few cells) positive. PAN-CK, P63, P40, β-catenin and CD34 negative. Ki67 is high, up to 80%.

She was started on the IFOS chemotherapy protocol. CT chest before commencing radiotherapy showed new nodules in the lower lobes. A chest x-ray below, taken 2 months later due to neutropenic fever, does not show any focal pathology:


Port-a-Cath with port in the right chest wall and tip of the catheter projected onto the superior vena cava.

Status post left mastectomy.

No evidence of infiltrate or mass.

About a half year later, complained of chest pain and shortness of breath.


Port-a-Cath properly placed in the right chest wall.

Status post-mastectomy.

Bilateral rounded pulmonary nodes and large masses.

Bilateral small pleural effusion.


Tip of Port-a-Cath properly placed.

Status post-mastectomy.

Bilateral lung metastases presenting as rounded nodules and huge heterogeneous vascular masses, the latter resembling the known primary breast tumor. Pleural-based mass bordering on the left lower lobe (LLL) bulges posteriorly into the erector spinae muscles and engulfs the posterior arch of the 6th rib, which shows lytic changes, "hair on end" periosteal reaction, and pathologic fractures.

Small amount of bilateral pleural effusion.

Lytic metastasis (not shown) in the body of the left iliac bone, breaching the cortex.

Case Discussion

A young woman presented to the ER with a massively enlarged left breast which she claimed had been significantly enlarged for the past year or so but had become painful several weeks previously, as well as enlarging further. On examination, the skin of the breast was erythematous. No fever or chills. History notable for Marfan syndrome, iron deficiency anemia, well-controlled schizophrenia, and depressive disorder.

US breasts demonstrated a huge heterogeneous mass with internal flow that was interpreted as having a low likelihood of malignancy, possibly granulomatous mastitis. The breast surgeon suspected phyllodes tumor. She underwent incision and drainage, with removal of necrotic tissue. Histopathology showed the mass to represent a high grade malignant phyllodes tumor. She underwent left mastectomy and received chemoradiotherapy. Despite this, 4 months after commencing treatment, a chest wall mass and lung metastases were seen on imaging.

A year after first presenting with the large breast mass, complained of pleuritic chest pain on the left and shortness of breath. X-ray and CT showed nodules and vascular masses in both lungs, as well as a mass enveloping a left rib. Shortly thereafter, she contracted COVID and being immunocompromised, succumbed to its complications.

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