Breast

• Cytologic variant of invasive lobular carcinoma (ILC)

• Aggressive variant which accounts for approximately 10% of ILC
• May show focal areas of classical ILC

• Predominant cytologic features determine the histologic type of ILC

• ILC are more common in older women (mean age 57, range 24 - 92) and very rare in men
• When they do occur in men, it is often in BRCA2 carriers

• CDH1 germline mutation is seen in many ILC tumors, resulting in the loss of E-cadherin gene expression in approximately 85% of ILC

• Diagnosis is often made on core needle biopsy
• Histologic tumor grade is assigned following the Nottingham grading system
• Reporting according to College of American Pathologists (CAP) invasive breast cancer protocol

• Tumors are most commonly detected as spiculated mass lesions on mammography
• Use of magnetic resonance imaging can aid in the detection of multicentric and contralateral lesions

• Factors which result in worse prognosis include high histologic grade (particularly high mitotic scores) and negative hormone receptor status
• Although the prognosis is typically worse for this variant versus the classic type ILC, it is thought to be more related to tumor grade versus variant type

• 48 year old with pancreatic metastasis (Diagn Pathol 2017;12:52)
• 49 year old woman with vertebral metastasis (Spine J 2016;16:e303)
• 89 year old woman (Int J Surg Pathol 2018;26:434)
• Periocular breast carcinoma metastasis (Ophthal Plast Reconstr Surg 2017;33:361)

• Similar to that of invasive ductal carcinoma and depends on the tumor pathologic stage and hormone receptor status

• Spiculated mass with ill defined margins; often no mass because of diffuse growth pattern

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• Moderately to poorly differentiated carcinomas
• Multifocal nodular aggregates of pleomorphic, high grade tumor cells with grade 2 - 3 nuclei which may contain prominent nucleoli
• Typical single file pattern or targetoid growth in a background of dense fibrotic breast parenchyma
• Distinctive cytologic cellular features with abundant eosinophilic cytoplasm (may look apocrine), signet ring and plasmacytoid cells
• Commonly positive for apocrine marker GCDFP-15
• Prognosis is related to the high tumor grade

Contributed by Mirna B. Podoll, M.D.



Contributed by Mark R. Wick, M.D.


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Images hosted on other servers:

Contributed by Mark R. Wick, M.D.

Which of the following is true of pleomorphic variant of invasive lobular carcinoma?


1. Are usually hormone receptor negative
2. Do not show HER2 overexpression
3. Frequency of p53 expression is similar to that of classic ILC
4. The aggressive nature of these tumors is reflected by the pleomorphic variant designation
5. The high histologic grade contributes to the poor patient outcomes

E. The aggressive nature of the pleomorphic variant of invasive lobular carcinoma (ILC) and poorer outcomes are related to the high histologic grade of this variant, rather than the pleomorphic designation itself. While these tumors may be ER and PR negative in approximately 5 - 10% of cases, the majority are hormone receptor positive. HER2 expression can be seen in approximately 20% of cases. In addition, the pleomorphic variant of ILC more commonly shows p53 expression when compared to the classic type ILC.

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Reference: Pleomorphic lobular carcinoma