Ductal Carcinoma In Situ (DCIS)

Common sites:

Gross features:

Histologic features:

• malignant cells limited to ducts and lobules
• note that with apocrine metaplasia, you should have a higher threshold for atypia
• cells “respect” eachother – keeping their distance
• nuclei uniform-appearing
• myoepithelial cells present (may be decreased in number)
• >1 duct involved
• completely filled by neoplastic cells (not just FEA)
• >2mm in size
• architectural types:
• comedocarcinoma:
• solid sheets of pleomorphic cells
• central necrosis
• dystrophic calcifications
• high-grade nuclei
• periductal concentric fibrosis and chronic inflammation
• non-comedo DCIS:
• monomorphic cell population
• nuclear grades range from low to high
• cribriform DCIS:
• cookie-cutter intraepithelial spaces, evenly distributed, regular in shape
• papillary DCIS:
• delicate fibrovascular cores lined by monomorphic tall columnar cells
• no myoepithelial layer in fibrovascular cores
• micropapillary DCIS:
• pseudopapillae with a narrow base and often bulbous or complex outgrowths
• Grade I:
• monotonous
• 1.5 to 2.0 RBC diameters
• Widely dispersed chromatin
• Occasional nucleoli only
• Grade II:
• Not grade I or grade III
• Grade III:
• Markedly pleomorphic nuclei
• > 2.5 RBC diameters usually
• Coarse chromatin
• Prominent or multiple nucleoli

Immunophenotype:

Marker:	Sensitivity:	Specificity:
ER/PR (all cells staining)
CK5/6 (neg)

Molecular features:

• important prognostic factors:
• grade
• size
• margins

Other features:

• mammogram showing microcalcifications forming in ductal patterns