Case number:	079
Age:	41
Clinical presentation:	Premenopausal woman with increased risk of developing breast cancer presented with history of right breast lump noticed 1 day ago on breast self-examination. She has family history of cervical carcinoma and tongue cancer.

Mammography:

Breast composition:	ACR category b (there are scattered areas of fibroglandular density)
Mammography features:

‣ Location of the lesion:	Right breast, upper outer quadrant at 10 o’clock, middle third
‣ Mass:
• Number:	3
• Size:	1.5 cm, 1.0 cm, and 0.9 cm in greatest dimension
• Shape:	Irregular
• Margins:	Obscured
• 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

Ultrasound:

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

‣ Mass
• Location:	Right breast, upper outer quadrant at 10 o’clock
• Number:	3
• Size:	1.4 × 1.0 cm, 1.0 cm, and 0.9 cm
• Shape:	Irregular
• Orientation:	Not parallel
• Margins:	Angular
• Echo pattern:	Hypoechoic
• Posterior features:	No posterior features
‣ Calcifications:	None
‣ Associated features:	Vessels in rim
‣ Special cases:	None

BI-RADS:

BI-RADS Category: 5 (highly suggestive of malignancy)

Further assessment:

Further assessment advised: Referral for cytology

Cytology:

Cytology features:

‣ Type of sample:	FNAC (solid lesion)
‣ Site of biopsy:
• Laterality:	Right
• Quadrant:	Upper outer
• Localization technique:	palpation
• Nature of aspirate:	whitish
‣ Cytological description:	Very cellular smears with highly pleomorphic malignant cells in loose clusters.
‣ Reporting category:	Malignant
‣ Diagnosis:	Carcinoma – high grade
‣ Comments:	None

Histopathology:

Breast-conserving surgery

Histopathology features:

‣ Specimen type:	Breast-conserving surgery
‣ Laterality:	Right
‣ Macroscopy:	On serial sectioning, the following four firm areas are identified: Area 1: Well-circumscribed area 1.6 × 1.5 × 1.5 cm. Cut surface is greyish white. Located 1.5 cm from the anterior margin, 2.8 cm from the medial margin, 2.5 cm from the lateral margin, 1.0 cm from the inferior margin, and 3.5 cm from the base. Area 2: 1.3 × 1.2 × 1.0 cm, located 2.0 cm below the first lump. Area 3: 3.5 × 1.5 × 1.5 cm, located 2.5 cm lateral to the first lump. This area shows whitish areas of fibrosis. Area 4: 1.5 × 0.6 × 0.6 cm, located 3.0 cm medial to the first lump.
‣ Histological type:	Invasive breast cancer of no special type with medullary pattern
‣ Histological grade:	Grade 3 (3 + 3 + 3 = 9)
‣ Mitosis:	25
‣ Maximum invasive tumour size:	Largest 1.6 cm in greatest dimension, two other nodules 0.5 cm and 0.4
‣ Lymph node status:	1/32
‣ Peritumoural lymphovascular invasion:	Not identified
‣ DCIS/EIC:	Not identified
‣ Margins:	Free
‣ Pathological stage:	pT1(3)N1
‣ Biomarkers:
‣ Comments:	Sections from the first firm area (1), fourth firm area (4), and focal parts of second firm area (2) show features of medullary carcinoma with dense lymphocytic infiltrate and tumour circumscription with rounded tumour margins. The largest tumour (1) is 1.6 cm in greatest dimension, microscopically. Multiple sections from the third firm area (3) show features of benign proliferative breast disease and sclerosis

Case summary:

Premenopausal woman presented with a lump in the right breast. Diagnosed as right breast carcinoma (multifocal), BI-RADS 5 on imaging, as high-grade breast carcinoma on cytology, and as medullary carcinoma, pT1(3)N1 on histopathology.

Learning points:

According to the WHO Classification of Tumours of the Breast, 5th edition, carcinomas historically described as medullary carcinoma, atypical medullary carcinoma, and/or carcinoma with medullary features are no longer considered a distinct morphological subtype. They are now categorized under invasive breast carcinoma of no special type with inclusion of descriptive modifiers referring to medullary pattern or basal-like features. (WHO Classification of Tumours Editorial Board. Breast tumours. Lyon (France): International Agency for Research on Cancer; 2019. (WHO classification of tumours series, 5th edition; vol. 2)).