Findings: The mammogram demonstrates a 1.5 cm. rounded mass with spiculated margins and a small "comet tail" in the central inferior aspect of the right breast. No associated calcifications are seen.

The sonographic examination reveals a lesion of mixed echogenicity and fairly well-defined, but irregular margins. Note is also made of unilateral shadowing posteriorly. The lesion has a vertical orientation perpendicular to the direction of the breast tissue. All of these descriptives are consistent with malignancy.

Diagnosis: Infiltrating ductal carcinoma of breast, mucinous/colloid type, revised Bloom-Richardson Grade II of III.

Discussion: Colloid carcinoma is a relatively rare malignancy, making up less than 5% of breast cancers. It is a well-differentiated subtype of invasive ductal carcinoma. The tumor cells secrete significant amounts of mucin. It tends to occur in older women. It grows slowly and has a fairly good prognosis.

Colloid cancers typically are relatively well-circumscribed rounded masses. Its appearance may suggest benignity with a rounded shape and well-circumscribed margins. However, spot compression magnification views often demonstrate indistinct margins.

References:
Basset LW, et al. Diagnosis of Diseases of the Breast,
Philadelphia. W. B. Saunders Co., 1997.

ACR Self-Evaluation Set 36. Breast Disease (Second Series), 1993.

Return to Women's Diagnosic Imaging Page