Benign breast conditions can mimic breast cancer on PET/CT imaging. The most common cause of benign FDG uptake in the breast is inflammatory lesions. PET/CT is used along with other imaging like mammography and MRI to make a diagnosis. Common benign causes of FDG uptake include dense breast tissue, fat necrosis, lactation, silicone implants or granulomas, infection, trauma, and benign breast tumors. While normal breast tissue FDG uptake depends on density and menopausal status, benign conditions like fat necrosis, lactation, silicone rupture, infection, and benign tumors can have increased FDG uptake. Poorly FDG-avid cancers, lobular carcinoma, DCIS, and small tumors are also important considerations in

1. Benign Breast Disease
on PET/CT imaging

2. Terminology
• Benign conditions in breast may mimic breast
carcinoma on PET/CT.
• Inflammatory lesions are most common cause
for benign FDG uptake in breast.

3. Top differential diagnosis
• Top differential considerations for benign FDG
uptake in breast include:
- poorly FDG-avid tumors such as DCIS, lobular
carcinoma.
- small tumors (< 2.5 cm)

4. IMAGING
• PET/CT is used in conjunction with other imaging modalities,
such as mammography, sonography, and breast MR to make
diagnosis.
• Common benign causes for FDG uptake on PET include
dense breast tissue, fat necrosis, lactation, silicone
rupture/granulomas, infection, trauma, recent interventional
procedures, and benign breast conditions such as
fibroadenomas and fibrocystic change.
• Benign breast conditions without significant FDG uptake
include cystic lesions, cystic tumors, intramammary nodes, and
some benign breast tumors .

5. Nuclear Medicine Findings

6. ○ Normal breast tissue
– FDG uptake is proportional to tissue density and hormonal/menopausal status.
□ Dense breasts have significantly↑ FDG uptake compared to fatty breasts.
□ Breasts in premenopausal patients demonstrate↑ FDG uptake compared to postmenopausal
patients.
□ ↑ SUV in central breast as opposed to peripheral breast (more fatty tissue in peripheral breast).
– Breast density typically decreases with increasing age; however, no significant correlation
between age and normal breast tissue FDG uptake.
fatty breasts
Dense breasts

7. Fat necrosis
– May exhibit ↑FDG uptake from various traumatic events/interventions.
□ Most common etiologies: Breast trauma, diagnostic interventions & surgical procedures.
– Sterile inflammatory process 2° to previous breast trauma, diagnostic procedure, or surgery.
□ TRAM reconstruction: Typically ↑ FDG uptake along incisional margins 2° to fat necrosis.
– ↑ FDG uptake 2° to metabolically active inflammatory cells.

8. Lactation
– Lactating glandular tissue: Intense, nearly symmetric FDG uptake
□ Slight asymmetry between breasts normal.
– Breast tissue proliferates with lactation and involutes with breastfeeding
cessation.
– Increased FDG uptake physiologically related to infant suckling.
□ Intracellular trapping of radiotracer in active glandular tissue.
– FDG uptake returns to normal within 3-4 weeks of breastfeeding cessation.

9. Implants/silicone rupture
– Leaking silicone implants or silicone granulomas: ↑ FDG uptake
(typically intense).
□ Saline implants more rarely demonstrate FDG Uptake.
□ MR remains modality of choice for silicone rupture.
– ↑ FDG uptake at rim of calcific capsulitis.

10. Infection
– Acute or chronic, including overlying skin.
– ↑ FDG uptake 2° to mastitis, abscess, TB and fungal Infections and post-
radiation.
Reactive axillary, internal mammary, axillary lymph nodes: ↑ FDG uptake.
– Activated inflammatory cells demonstrate increased glucose transporters.
□ Same physiologically as malignant cells.

11. Post intervention
– Focal ↑ FDG uptake due to core biopsy, recent surgery or
radiotherapy.
□ May persist for several weeks
– Leukocyte infiltration of granulation tissue involved in wound
repair.
□ Resorption of necrotic debris and hematoma.

12. Benign breast conditions
– Variable ↑ uptake in fibroadenomas, phyllodes tumors, fibrocystic
change, and inspissated cysts.
□ ↑ FDG in fibroadenomas and phyllodes tumors 2° to high proliferation
and rapid growth.
– Ductal ectasia, typical/atypical hyperplasia, apocrine Metaplasia.
□ Often mildly ↑ FDG above normal glandular tissue
phyllodes tumor

13. DIFFERENTIAL DIAGNOSIS:
Poorly FDG-Avid Breast Cancer
• Concurrent chemotherapy or radiation treatment
○ May have decreased uptake in areas of viable tumor.
○ Predictive of good response to chemotherapy/radiation.
• Lobular or tubular carcinoma
○ Typically low FDG uptake 2° to low-grade tumor
○ With aggressive behavior, may show ↑ FDG uptake
• Ductal carcinoma in situ (DCIS)
○ Variable linear/branching areas of FDG uptake
– Greater sensitivity with high-resolution positron emission
mammography (PEM) units than conventional PET scanners.
• Small tumors
○ Partial volume effects decrease measured SUV in tumors < 2.5
cm in diameter (false-negative).

14. THANK YOU