Case number:	125
Age:	56
Clinical presentation:	Postmenopausal woman with average risk of developing breast cancer presented with a right breast lump and mastalgia of duration 1 week. Examination revealed a soft palpable right breast lump.

Mammography:

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

‣ Location of the lesion:	Right breast, multiple lesions in all quadrants, largest in upper outer quadrant at 10 o’clock, middle third
‣ Mass:
• Number:	Multiple
• Size:	Largest 3.8 × 3.0 cm
• Shape:	Oval
• Margins:	Circumscribed
• Density:	High
‣ 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

Mammography features:

‣ Location of the lesion:	Left breast, multiple lesions in all quadrants, largest in upper outer quadrant at 2 o’clock, posterior third
‣ Mass:
• Number:	Multiple
• Size:	Largest 1.2 × 1.0 cm
• Shape:	Round to oval
• Margins:	Circumscribed
• Density:	High
‣ 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, all quadrants

‣ Mass
• Location:	Right breast, all quadrants
• Number:	Multiple
• Size:	Largest 3.5 × 3.0 cm at 8 o’clock position, 3.5 cm from nipple and at 1.8 cm skin depth
• Shape:	Round to oval
• Orientation:	Not parallel
• Margins:	Circumscribed
• Echo pattern:	Hypoechoic
• Posterior features:	No posterior features
‣ Calcifications:	None
‣ Associated features:	Vascularity: in rim and internal
‣ Special cases:	None

Ultrasound features: Left breast, all quadrants

‣ Mass
• Location:	Left breast, all quadrants
• Number:	Multiple
• Size:	Largest 1.2 × 0.65 cm at 9 o’clock position, 1.7 cm from nipple and at 0.3 cm skin depth
• Shape:	Round to oval
• Orientation:	Not parallel
• Margins:	Circumscribed
• Echo pattern:	Hypoechoic
• Posterior features:	No posterior features
‣ Calcifications:	None
‣ Associated features:	Vascularity: in rim and internal
‣ Special cases:	None

BI-RADS:

BI-RADS Category: 4C (high suspicion for malignancy)

Further assessment:

Further assessment advised: Referral for cytology, for core biopsy and further imaging with breast MRI

MRI:

MRI features:
‣ MRI features:		Amount of fibroglandular tissue: ACR category a (the breasts are almost entirely fatty). Background parenchymal enhancement: Minimal (< 25%), symmetrical

‣ Location:		Bilateral breasts – multiple of varying sizes
‣ Focus:		No
‣ Mass:
• Shape:	Round
• Margin:	Circumscribed
• Internal enhancement:	Homogenous
• Kinetic curve:	Type 3
‣ Non-mass enhancement:
• Distribution:	No
• Internal enhancement:	No
‣ Non-enhancing findings:		No
‣ Associated features:		No
‣ Axillary nodes:		No

Cytology:

Cytology features:

‣ Type of sample:	FNAC
‣ Site of biopsy:
• Laterality:	Right
• Quadrant:	7 o’clock
• Localization technique:	Palpation
• Nature of aspirate:	whitish
‣ Cytological description:	Smears are very cellular and show a pleomorphic population of malignant ductal cells arranged as dyscohesive cell clusters. Single isolated malignant cells are also seen
‣ Reporting category:	Malignant
‣ Diagnosis:	Carcinoma
‣ Comments:	None

Cytology features:

‣ Type of sample:	FNAC
‣ Site of biopsy:
• Laterality:	Left
• Quadrant:	Lesion 1: 4’o clock lesion. Lesion 2: 1 o’clock near axillary tail. Lesion 3: 9 o’clock
• Localization technique:	Ultrasound-guided
• Nature of aspirate:	Thick whitish material obtained from all three areas
‣ Cytological description:	Smears from all three lesions reveal very cellular smears with loosely cohesive cells, which are pleomorphic and hyperchromatic with a high N:C ratio. Background shows RBCs
‣ Reporting category:	Malignant
‣ Diagnosis:	Carcinoma
‣ Comments:	None

Case summary:

Postmenopausal woman presented with recent-onset right breast lump with mastalgia. Multiple variable-sized lesions of suspicious morphology are seen in both breasts, diagnosed as BI-RADS category 4C on imaging and carcinoma bilateral breast on cytology. Further detailed evaluation was done at a higher centre. Right breast core biopsy revealed moderately differentiated neuroendocrine carcinoma, favour metastasis. PET scan performed to look for primary site of malignancy revealed mass lesion at tail of pancreas; biopsy proved neuroendocrine tumour of pancreas. PET scan also revealed metastatic foci in liver and vertebrae. Liver biopsy revealed high-grade neuroendocrine carcinoma, primary likely from gastrointestinal tract, thyroid, or pancreatic tumour. Final diagnosis: Pancreatic neuroendocrine tumour with distant metastasis to liver, vertebrae, and bilateral breasts.

Learning points:

Metastatic solid tumours in the breast account for 0.2–1.1% of all breast malignancies; 0.02–0.4% are caused by systemic involvement by haematological malignancies. Malignant melanomas and carcinomas of the lung, ovary, kidney, and stomach are the most common primary sites from which breast metastasis occurs. Most of the lung tumours are the small cell neuroendocrine type. A panel of breast markers (GCDFP-15, mammaglobin, GATA3) may be helpful if doubt exists whether the tumour represents a breast primary.