Case number:	031
Age:	45
Clinical presentation:	Premenopausal woman with average risk for developing breast cancer presented with left breast lump of 2 years duration, slowly growing in size. Examination revealed 2 cm diameter lump in upper outer quadrant of left breast.

Mammography:

Breast composition:	ACR category c (the breasts are heterogeneously dense, which may obscure small masses)
Mammography features:

‣ Location of the lesion:	Left breast, upper quadrants, central zone, anterior third
‣ Mass:
• Number:	1
• Size:	2.4 cm in greatest dimension
• Shape:	Oval
• Margins:	Circumscribed
• Density:	Equal
‣ 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

Breast composition:	ACR category c (the breasts are heterogeneously dense, which may obscure small masses)
Mammography features:

‣ Location of the lesion:	Both axillae
‣ Mass:
• Number:	None
• Size:	None
• Shape:	None
• Margins:	None
• Density:	None
‣ Calcifications:
• Typically benign:	None
• Suspicious:	None
• Distribution:	None
‣ Architectural distortion:	None
‣ Asymmetry:	Present, both axillae
‣ Intramammary node:	None
‣ Skin lesion:	None
‣ Solitary dilated duct:	None
‣ Associated features:	Accessory breast tissue in both axillae, left more than right

Ultrasound:

Ultrasound features: Left breast, central portion of the breast at 12 o'clock

‣ Mass
• Location:	Left breast, central portion of the breast at 12 o'clock
• Number:	1
• Size:	2.1 × 1.3 cm
• Shape:	Oval
• Orientation:	Parallel
• Margins:	Circumscribed
• Echo pattern:	Heterogeneous
• Posterior features:	Posterior Enhancement
‣ Calcifications:	None
‣ Associated features:	Internal vascularity
‣ 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:	Left
• Quadrant:	Subareolar
• Localization technique:	Palpation
• Nature of aspirate:	2 mL of clear brownish fluid
‣ Cytological description:	Smears show tightly cohesive sheets of benign ductal epithelial cells with many cells showing apocrine metaplasia. Apocrine cells have abundant granular cytoplasm. Numerous cyst macrophages are seen in the background with proteinaceous cyst fluid
‣ Reporting category:	Benign
‣ Diagnosis:	Fibrocystic change
‣ Comments:	None

Case summary:

Premenopausal woman presented with left breast lump. Diagnosed as BI-RADS 2 on imaging and as fibrocystic change on cytology. An incidental finding was accessory breast tissue in both axillae.

Learning points:

Mammary tissue can be seen in extramammary locations, the commonest being in the axillae as in this case. This accessory breast tissue was detected incidentally during imaging being done for left breast fibrocystic lump evaluation.
Fibrocystic changes beginning with breast involution are commonly seen in the fourth and fifth decades. Complicated cyst is part of the spectrum of fibrocystic changes. Regular follow-up to monitor regression in the postmenopausal stage relieves the anxiety of possible malignancy.