Mass Shape — Round
Round is a mass shape descriptor indicating a spherical or ball-shaped mass, similar in diameter in all three axes.
Definition
A mass that is spherical or ball-shaped — approximately equal diameter in all three axes.
Imaging Appearance
- Spherical contour on all planes
- All diameters approximately equal
- Smooth or irregular surface possible
Differential Diagnosis
Round masses occur in both benign and malignant conditions:
- Cyst — round, circumscribed, no enhancement (benign)
- Fibroadenoma — round, circumscribed (benign)
- Invasive ductal carcinoma — round with indistinct or thick rim enhancement (suspicious)
- Metastases — may be round, multiple
Example Pathologies from Source Figures
- Round, indistinct, heterogeneous → IDC
- Round, indistinct, thick rim enhancement → IDC
- Round, circumscribed, heterogeneous → Fibroadenoma
Pitfalls
- Round shape is not inherently benign or suspicious — the margin and enhancement pattern are the key discriminators
- Round + circumscribed + T2 hyperintense may suggest a cyst or fibroadenoma, but must not have enhancement to classify as a simple cyst