Case Two – February 2017

  • Patient Information
    • 73 year old female presented with an erythematous, scaly, and eroded plaque on the right nipple.
    • No personal or family history of breast cancer.
    • Physical examination failed to reveal a palpable breast mass.
    • Biopsy was performed after the lesion was unresponsive to topical corticosteroids.
  • Clinical Diagnosis
    • Irritant contact dermatitis
    • Mammary Paget disease
    • Squamous cell carcinoma
  • Histology

     

    • There is a proliferation of enlarged epithelioid cells distributed at all levels of the epidermis in pagetoid array with abundant vacuolated cytoplasm.

     

     

    • The tumor cells exhibit nuclear pleomorphism and atypical mitotic figures are present.

     

    Immunohistochemistry:

    • Positive for EMA and Cam5.2
    • Negative for p63, estrogen receptor (ER), progesterone receptor (PR), and mucicarmine

     

    Histologic Differential Diagnosis:

    • Mammary Paget disease
    • Squamous cell carcinoma in situ with Bowenoid features
  • Final Diagnosis

    “Anaplastic” Mammary Paget Disease

    • This variant of mammary Paget disease shows striking cytologic atypia and mimics pagetoid Bowen disease histologically.
    • The tumor cells in mammary Paget disease typically show positive staining for CEA, EMA, CK7, Cam5.2 and cytokeratin AE1/AE3.
    • The anaplastic variant of mammary Paget disease is often negative for mucin special stains (such as Alcian blue and mucicarmine), which was seen in our case.
    • While CK7 is often positive in mammary paget disease, it may also be positive in a subset of squamous cell carcinomas.
    • Some examples of anaplastic mammary Paget disease also show acantholysis.
    • Clues to the diagnosis of anaplastic mammary Paget disease include the absence of dyskeratotic cells and desmosomes, presence of intracellular mucin/signet ring cells, and positive staining for CEA and EMA.

     

    What is this tumor, and why should I know about it?

    • Anaplastic mammary Paget disease can mimic pagetoid Bowen disease histologically.
    • The anaplastic variant of mammary paget disease may be associated with an increased risk of underlying invasive carcinoma, even in the absence of a palpable mass.
  • Summary
    • Anaplastic Paget disease mimics pagetoid Bowens disease histologically.
    • This variant is negative for mucin special stains (Alcian blue and mucicarmine) and may show acantholysis.
    • Positive staining for CEA and EMA favor a diagnosis of anaplastic mammary Paget disease over pagetoid Bowen disease.
    • Even with the absence of a palpable mass, anaplastic mammary Paget disease may be associated with increased risk of an underlying invasive breast cancer compared to conventional Paget disease.