Case number:	010
Age:	78
Clinical presentation:	Postmenopausal woman with average risk of breast cancer underwent CT scan of the chest for retrosternal enlargement of thyroid. The scan revealed an incidental presence of right breast lump. Examination revealed lumpish nodularity in both breasts.

Mammography:

Breast composition:	ACR category a (the breasts are almost entirely fatty)
Mammography features:

‣ Location of the lesion:	Right breast, upper outer quadrant at 10 o’clock, middle third
‣ Mass:
• Number:	1
• Size:	4.0 × 3.0 cm
• Shape:	Oval
• Margins:	Circumscribed
• Density:	Equal with fat-containing areas
‣ Calcifications:
• Typically benign:	None
• Suspicious:	None
• Distribution:	None
‣ Architectural distortion:	None
‣ Asymmetry:	None
‣ Intramammary node:	None
‣ Skin lesion:	None
‣ Solitary dilated duct:	None
‣ Associated features:	None

Ultrasound:

Ultrasound features: Right breast, upper outer quadrant at 10 o’clock

‣ Mass
• Location:	Right breast, upper outer quadrant at 10 o’clock
• Number:	1
• Size:	3.6 × 2.0 cm
• Shape:	Oval
• Orientation:	Parallel
• Margins:	Circumscribed
• Echo pattern:	Heteroechoic
• Posterior features:	No posterior features
‣ Calcifications:	None
‣ Associated features:	None
‣ Special cases:	None

BI-RADS:

BI-RADS Category: 2 (benign)

Further assessment:

Further assessment advised: Referral for cytology

Cytology:

Cytology features:

‣ Type of sample:	FNAC
‣ Site of biopsy:
• Laterality:	Right
• Quadrant:	Upper outer
• Localization technique:	Ultrasound-guided, because non-palpable
• Nature of aspirate:	Yellowish fatty, greasy material
‣ Cytological description:	Overall low cell yield. Bimodal population of cohesive epithelial cells in small groups and single bipolar nuclei of non-neoplastic glandular breast tissue. Many adipose tissue fragments seen in the background
‣ Reporting category:	Benign
‣ Diagnosis:	Non-neoplastic glandular breast tissue
‣ Comments:	None

Case summary:

Postmenopausal woman presented with bilateral breast nodularity. Diagnosed as hamartoma (fibroadenolipoma), BI-RADS 2 on imaging and as non-neoplastic glandular breast tissue on cytology.

Learning points:

Breast hamartoma is uncommon and accounts for less than 1% of all benign breast lesions.
Mammary hamartoma is defined as a combination of ducts, lobules, collagenous stroma, and adipose tissue present as a relatively circumscribed lesion. Morphologically, it can exhibit a wide diversity of appearances, depending on the proportions of epithelial and stromal elements, the latter including fat.
The appearance on mammography is thus variable and depends upon the predominant component. Usually it is seen as an ovoid well-circumscribed encapsulated mass lesion with soft tissue and fat densities, giving a “breast within a breast appearance” that ranges from 1 cm to 17 cm. There are no macrocalcifications or microcalcifications within. The skin and the nipple–areola complex are normal, and there is no axillary lymphadenopathy.