PA30.1-5 | Breast — Practice Quiz

A 28-year-old woman presents with a 2 cm, firm, rubbery, freely mobile breast lump. She says it seems slightly larger just before her periods. Biopsy shows a biphasic tumour with compressed, elongated ductal structures surrounded by a loose, fibroblastic stroma. No stromal hypercellularity or mitoses are seen. Which of the following best describes this lesion?

A 35-year-old woman undergoes excision of a 6 cm breast lump that has rapidly enlarged over 3 months. Gross examination reveals a fleshy, leaf-like tumour that bulges into the cut surface. Histology shows leaf-like stromal projections lined by epithelium, with markedly hypercellular stroma and 12 mitoses per 10 high-power fields. The stromal cells show nuclear pleomorphism and there are areas of necrosis. What is the most appropriate diagnosis?

A mammogram in a 52-year-old woman shows a 1.5 cm cluster of pleomorphic microcalcifications in the upper outer quadrant. Biopsy shows large, pleomorphic epithelial cells filling a duct with central necrosis and calcification. There is no breach of the basement membrane. Immunohistochemistry shows ER−, PR−, HER2 3+ (strongly positive). What is this lesion and its subtype?

A 58-year-old woman undergoes mastectomy for breast carcinoma. Histology shows small, monomorphic tumour cells infiltrating the stroma in single-file linear cords and targetoid patterns around pre-existing ducts (concentric fibrosis). Immunohistochemistry reveals loss of E-cadherin expression. The tumour is ER+, PR+, HER2−. Which diagnosis and molecular subtype best describes this carcinoma?

A 45-year-old woman presents with a 10-day history of a rapidly enlarging, warm, erythematous, peau d'orange breast. She is afebrile and inflammatory markers are only mildly elevated. A core biopsy is taken from the erythematous skin. Histology shows carcinoma emboli in dermal lymphatic channels, with no significant acute inflammatory infiltrate. What is the most likely diagnosis?

A 63-year-old woman presents with eczematoid changes — crusting, scaling, and erosion — confined to the nipple and areola for 4 months. A punch biopsy of the nipple skin shows large, pale cells with prominent nucleoli scattered within the epidermis. The underlying breast is not palpable. ER immunostain on the intraepidermal cells is positive. Which of the following is the most accurate statement about this condition?

A 38-year-old woman's breast carcinoma is sent for biomarker assessment. The pathologist reports: ER 90% strong nuclear staining (H-score 280), PR 60% positive, HER2 IHC 1+ (negative by FISH), Ki-67 8%. Nottingham histological grade is 1 (tubule formation 1 + nuclear pleomorphism 1 + mitotic count 1). Which molecular subtype does this correspond to, and what is the clinical implication?

A 22-year-old woman presents with a tender, ill-defined mass in the right breast 3 weeks after starting to breastfeed her first baby. She has fever (38.8°C) and erythema over the affected quadrant. Fine-needle aspiration yields creamy pus. Gram stain shows clusters of Gram-positive cocci. Which pathological process best describes this condition, and what is the most common causative organism?

A breast specimen from a 48-year-old woman shows a poorly defined, stellate mass of 2.2 cm. Histology reveals an invasive carcinoma with tubule formation scoring 3, nuclear pleomorphism scoring 3, and mitotic count of 22 per 10 high-power fields scoring 3. Lymphovascular invasion is present. Three of twelve axillary lymph nodes contain metastases. What is the Nottingham grade and pathological TNM stage (assuming no distant metastasis)?

A 55-year-old man presents with bilateral, tender, subareolar breast enlargement over 4 months. He has chronic kidney disease on haemodialysis and is being treated with spironolactone. Biopsy of the subareolar tissue shows proliferation of ducts with peri-ductal oedematous stroma, and the stroma contains a lymphocytic infiltrate. No atypical cells are seen. Which of the following best explains the pathogenesis?

A pathologist examines two core biopsies side by side. Specimen A: circumscribed mass with a compressed duct enclosed within a dense fibrous capsule; epithelial cells are small, uniform, without atypia; stroma is fibrous with low cellularity. Specimen B: irregular stellate mass; cells infiltrate fat in haphazard cords; cells show nuclear pleomorphism (3×), prominent nucleoli, and nuclear moulding; mitoses 4/10 HPF; desmoplastic stroma. Based on these morphological features alone, which is the correct identification?

A 32-year-old woman sustains blunt trauma to the left breast during a road traffic accident. Two months later she presents with a painless, firm, irregular lump at the site of injury. Mammography shows an irregular density with coarse 'eggshell' calcifications. A core biopsy is performed. Histology reveals foamy macrophages, haemosiderin-laden macrophages, necrotic adipocytes with cyst formation, and surrounding fibrosis. No malignant cells are seen. What is the diagnosis and the most important clinical consideration?