Breast malignant, males, children
In situ carcinoma
Pleomorphic lobular carcinoma in situ (PLCIS)

Author: Sucheta Srivastava, M.D.

Revised: 11 December 2017, last major update November 2017

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Pleomorphic lobular carcinoma in situ "PLCIS"

Cite this page: Srivastava, S. Pleomorphic lobular carcinoma in situ (PLCIS). PathologyOutlines.com website. http://pathologyoutlines.com/topic/breastmalignantpleolcis.html. Accessed December 13th, 2017.
Definition / general
  • Lobulocentric proliferation of cells which are significantly pleomorphic and large when compared to classic LCIS
Essential features
  • Cytological features resemble high grade DCIS rather than classic LCIS
    • Marked acinar expansion
    • Cellular dyshesion
    • Abundant, dense eosinophilic cytoplasm
    • Large nuclei (≥ 4x larger than a lymphocyte)
    • Pleomorphism: 2 - 3x variation in nuclear size and shape
ICD-10 coding
  • D05 carcinoma in situ of breast
    • D05.0 lobular carcinoma in situ of breast
    • D05.00 lobular carcinoma in situ of unspecified breast
    • D05.01 lobular carcinoma in situ of right breast
    • D05.02 lobular carcinoma in situ of left breast
Epidemiology
Clinical features
  • Many cases of PLCIS lack specific clinical features
  • Radiology description
    • PLCIS not associated with invasive carcinoma: abnormal microcalcifications are the most common radiological finding which can be an isolated finding or associated with architectural distortions / asymmetric density; rarely isolated finding of a spiculated mass or a nodule
    • PLCIS associated with invasion: radiological finding could be a palpable mass with associated abnormal mammographic findings (architectural distortions) with or without suspicious calcifications
    Prognostic factors
    • Natural history of PLCIS not associated with invasive carcinoma remains largely unknown
    • PLCIS may be frequently associated with invasive disease and has a more aggressive course
    • Given the increased genomic instability reported for PLCIS there is speculation that the risk of subsequent breast cancer is higher than that conferred by classic LCIS
    • PLCIS is considered to be a precursor of invasive cancer in addition to a marker of increased risk
    • PLCIS is frequently multifocal and extensive and positive / close margins are common in the setting of breast conserving surgery
    • Cases with isolated PLCIS are less likely / rarely recur compared to those associated with invasive carcinoma
    • PLCIS has weaker ER expression than classic LCIS
    Case reports
    • Pleomorphic lobular carcinoma in situ of the breast composed almost entirely of signet ring cells (Pathol Int 2006;56:683)
    Treatment
    • Complete surgical excision is recommended due to high rate of upgrade following a diagnosis of PLCIS on core needle biopsy
      • At surgical excision, diagnosis is upgraded to DCIS in 15 - 25% and to invasive carcinoma in 30 - 60% (Breast J 2017 Sep 19 [Epub ahead of print])
      • Either classic or pleomorphic invasive lobular carcinoma or invasive ductal carcinoma
      • Suggests that PLCIS is a risk lesion, similar to classic LCIS
    • Current National Comprehensive Cancer Network (NCCN) guidelines [Accessed 17 November 2017] state that "clinicians may consider complete excision of PLCIS with negative margins" but also note that evidence on efficacy and outcomes associated with complete PLCIS excision are lacking
      • Some pathologists report PLCIS margin status; if margins are close or positive, surgical re-excision or RT is discussed with the patient
      • However, data is unclear, with variable reports of local recurrence after excision with positive PLCIS margin and no adjuvant RT or re-excision
    • PLCIS shares some morphologic and genetic features with DCIS; however, due to small number of cases it is not clear if these patients have a risk of local recurrence similar to low, intermediate or high grade DCIS, which could be critical in determining the role of adjuvant RT
    • Endocrine therapy has shown no benefit on local control in patients with ER+ PLCIS postexcision
    Gross description
    • Cut surface of breast tissue harboring PLCIS may have a faintly granular appearance when viewed with tangential light because affected lobules are sufficiently enlarged to be visible and microcalcifications are almost always present
    Microscopic (histologic) description
    • Pleomorphic LCIS is characterized by marked distention of the lobules filled with neoplastic cells
    • Cells are medium to large with high N:C ratio, dyscohesive and evenly spaced
    • Cytoplasm is moderate to abundant, dense eosinophilic or granular
    • Intracytoplasmic vacuoles are present with or without mucin; may be large enough to produce signet ring cell forms
    • Nuclei are ≥ 4x the size of a lymphocyte, eccentrically placed, often exhibit moderate to marked nuclear pleomorphism (> 2 - 3x variation in nuclear size) and distinct prominent nucleoli
    • Chromatin is coarse and mitotic figures can be seen
    • Binucleated and multinucleated cells are frequently seen (Am J Clin Pathol 2015;144:722)
    • Frequently associated with central, comedo type necrosis and calcifications
    • Clear cell change can be present similar to classic LCIS
    • Myoid form of PLCIS is characterized by cells with dark eosinophilic to basophilic cytoplasm and deeply basophilic eccentric nuclei resembling myoblasts
      • This appearance is seen typically in postmenopausal women, involves atrophic lobules and terminal ducts
      • It is probably due to cytoplasmic condensation and loss of cohesion and shrinkage of cells
    • Apocrine differentiation is seen sometimes, referred as apocrine PLCIS
      • This change is characterized by abundant eosinophilic cytoplasm, cytoplasmic granules and prominent nucleoli
      • Apocrine PLCIS appears to be a biologically distinct subtype which is GCDFP and AR positive
      • It is mostly (~80%) negative for ER and PR, has HER2 gene amplification in 1/3 of cases and has elevated Ki67 (> 10%) (Am J Surg Pathol 2009;33:1683)
    Microscopic (histologic) images

    Images hosted on PathOut server:

    Images contributed by Sucheta Srivastava, M.D.

    Characteristic microscopic features of PLCIS showing large, dyscohesive cells with abundant pink cytoplasm and intracytoplasmic vacuoles

    PLCIS with prominent comedo necrosis and microcalcifications


    ER staining (4x)

    PR

    E-cadherin staining (10x)

    HER2



    Images contributed by others

    In situ and invasive disease


    E-cadherin: in situ and invasive disease



    Images hosted on other servers:

    Various images

    E-cadherin: LCIS vs. DCIS

    Cytology description
    • Cells have abundant cytoplasm compared with classic LCIS
    • Nuclei are larger, more pleomorphic and frequently have nucleoli
    • Nuclei can have 2+ nuclei; may be lobulated or indented and eccentrically placed
    • Cells can resemble those of DCIS and E-cadherin is helpful to make that distinction
    • Intracytoplasmic mucin or signet ring cells can be present which can help to distinguish from DCIS
    Positive stains
    Negative stains
    • E-cadherin
    • Most cases are negative for HER2 overexpression
    Molecular / cytogenetics description
    • Genetic signature of 1q gain and 16q loss combined with the lack of E-cadherin expression observed in PLCIS supports the lobular lineage for PLCIS along the multistep cancer progression pathway
    • It is unclear whether PLCIS arises from classic LCIS and represents a genetically more advanced lesion or if PLCIS originates from a yet unidentified precursor lesion
      • In one case with synchronous classic LCIS and apocrine PLCIS, both lesions shared 1q gain and 16q loss with additional chromosomal changes present in the apocrine PLCIS; this suggests evolution from the same precursor or through the same genetic pathway (Am J Surg Pathol 2009;33:1683)
    • Some genetic abnormalities seen are HER2 amplification, cyclin D1 amplification, gain of 20q and loss of 17p and 13q
    • At least some PLCIS are nonobligate precursors of invasive PLC analogous to high grade DCIS and invasive ductal carcinoma
      • PLCIS and invasive PLC may develop through a molecular genetic pathway similar to classic lobular carcinoma, as these lesions harbor the hallmark molecular genetic features of lobular carcinoma (loss of 16q and gain of 1q) associated with lack of E-cadherin and β-catenin expression
      • These lesions show additional molecular genetic changes more analogous to high grade DCIS including gains of c-myc (8q24) and HER2 (17q12), gains on 8p, 8q and 13q and losses on 1p, 8p, 12p, 14q, 18q, 19p and 19q
    • PLCIS is characterized by amplification of HER2 and c-myc (8q24) oncogenes, which may account for (a) its higher grade and proliferation rate, (b) its more frequent progression to invasive carcinoma
    • PLCIS may evolve through a molecular genetic pathway similar to that of classic LCIS but in addition also undergo additional genetic events (e.g. c-myc and HER2 amplification)
    • PLCIS and invasive PLC are frequently associated with foci of classic lobular carcinoma and areas showing a morphological continuum between PLCIS and classic LCIS have also been described (J Pathol 2005;207:1)
    Differential diagnosis
    Board review question #1
    What is NOT a feature of PLCIS?

    1. Apocrine metaplasia
    2. Nuclei 4x the size of a lymphocyte
    3. Intracytoplasmic vacuoles
    4. Multinucleation
    5. Signet ring cells
    Board review answer #1
    A. Apocrine metaplasia
    Board review question #2
    Which of the following is NOT true for PLCIS?

    1. Precursor for invasive carcinoma
    2. Positive E cadherin
    3. Positive ER and AR
    4. Abundant, dense eosinophilic cytoplasm
    5. Signet ring cells
    Board review answer #2
    B. Positive E cadherin