GENERAL

• Invasive tumors with increased through transmission are 10-24x more likely to be high grade than invasive tumors without this feature. Thought to be related to high cellular content, organization of tumor cells, and/or lack of a desmoplastic reaction (due to rapid growth).

• Tumor markers are predictive of treatment response. Node status and tumor size remain the most important prognostic factors.

• Multifocal vs multicentric

  • Distinguishing b/n multifocal and multicentric CA is related to implication of surgical management.

  • Multifocal breast CA is 2 or more masses w/n 4 to 5 cm of each other, usually same quadrant.

  • Multifocal Ca may be treated w/ lumpectomy if the breast is large enough.

  • Multicentric usually require mastectomy

• Atypical lobular hyperplasia:

  • Found in TDLU and often incidental finding at bx

  • When ALH is most severe finding at core bx, excision is generally recommended due to the 15% risk of upgrade to DCIS

ATYPICAL DUCTAL HYPERPLASIA

• • • Core bx showing ADH should be followed by excision given the 15-20% rate of unsampled malignancy.

DCIS

• Typically presents with asx  calcs on mammography

  • Calcs are typically fine linear and pleomorphic

• <10% of cases presents as palpable mass or bloody nipple discharge.

• Can be diffuse

• Coexisting invasive carcinoma is present in 50% of cases of DCIS >2.5 cm

• DCIS is quoted to progress to invasive CA at a rate of 1% per year if left untreated. 

• Histologic grade usually of DCIS typically correlates with histologic grade of invasive tumor. Thus, high-grade DCIS is more worrisome than low-grade both for the association with upgrade to invasive carcinoma at lumpectomy and for the potential progression to high-grade invasive CA if left untreated.

• Histologic subtypes based on architecture

  • Comedo (central necrosis in duct lumen)

  • Noncomedo

  • Rare types

• Low-grade DCIS 

  • Refers to low nuclear grade ductal carcinoma in situ

  • Typically  presents with amorphous morphology

  • 30% chance of seeing calcs on US

  • Typically ER+ and PR+

  • Excellent cure rate if adequately treated

• High-grade DCIS 

  • Typically presents as pleomorphic morphology

  • 63% chance of seeing calcs on US 

INVASIVE DUCTAL CARCINOMA

• Presents as mass

• IDC not otherwise specified (NOS) is most common invasive breast CA.

• IDC subtypes have improved prognosis compared to IDC NOS. Not commonly associated with any of the special types.

• Several subtypes of well-differentiated IDC

  • Tubular carcinoma

  • Medullary

  • Papillary

  • Mucinous

• Clinical presentation

  • Can present as architectural distortion but less commonly than ILC

TUBULAR CARCINOMA

• Composed of well-differentiated tubular structures with open lumina lined by a single layer of epithelial cells.

• Presents as a small spiculated mass on mammography

• Can be stable for years

• 5 year survival is 95-98%

MUCINOUS CARCINOMA

• Circumscribed or nearly circumscribed appearance.

  • Circumscribed does NOT equal benign.

• 5 year survival rate is 89-95%

LCIS

• Not typically associated with calcs

• LCIS is usually an incidental finding on bx for amorphous calcifications

• Excision is recommended after core bx as there is 27% risk of upgrade to carcinoma.

• The relative risk of developing CA is 8-12x

• 10x risk of developing subsequent invasive carcinoma compared to 4x risk with ADH and ALH, and 2x risk with radial scar

• Difficult to detect due to insidious growth pattern

• Typically presents as an isolated architectural distortion or a spiculated mass on mammography

• Often seen only on CC view

• Not typically associated with calcs

• Invades as single file columns of cells.

• Represents about 10% of all breast CA

• Higher incidence of bilaterality, multicentricity, and multifocality compared to IDC

• Usually well differentiated (grade 1) in general and usually associated with posterior shadowing.

• Clinical presentation

  • Can result in a 'shrunken' breast with direct involvement of the overlying skin (T4b, stage IIIB)

  • Palpable thickening

  • 'Shrinking' breast and/or skin retraction

• Often diagnosed at a larger size and more advanced stage compared to infiltrating ductal carcinoma bc the tumor cells invade as single file columns more than forming a discrete mass.

• Clinical

  • Characterized by diffuse breast erythema, warmth, induration, and/or peau d-orange and sometimes pain

  • Can manifest as shrinking breast (just like invasive lobular carcinoma)

  • Typically enlarges the involved breast with erythema of skin 

  • Ipsilateral axillary LNs are usually involved by tumor

• Rarely seen in a pregnant of lactating women

• Can present as a complex cystic and solid mass

• Rapidly progressive hardening over several months with dense asymmetric mammogram should prompt this diagnosis

• Punch skin bx (performed by surgeon) is preferred to breast core bx to establish diagnosis

  • Skin bx will show tumor in dermal lymphatics

• Imaging cannot reliably distinguish inflammatory breast CA (with invasion of dermal lymphatics) from upstream lymphatic obstruction (without invasion of dermal lymphatics) due to locally advanced breast CA. Thus skin bx is required.

METS TO BREAST

• Morphologically, mets to the breast are round, circumscribed or slightly irregular without spiculations, calcifications, or architectural distortion.

• Can be seen with metastatic lung CA, melanoma, and lymphoma

RECURRENT CA