Case 70 - Discussion

Uploaded: 2007-11-29, Updated: 2007-11-29
 

 

Mucicarmine

Mucicarmine

CK7

CK7

CK20

AR

SCROTAL SKIN, RIGHT HEMISCROTUM, EXCISION:
- Extra mammary Paget's disease

 

Comment:

Multiple sections show extensive neoplastic involvement of the epidermis. Neoplastic cells are strongly positive with Cytokeratin 7, moderately positive with CK20, negative for estrogen receptor and moderately positive with antigen receptor. Melanosome markers, Mart-1 and Melan-A are negative. Mucin stain show focal positive. These findings are consistent with extra-mammary Paget's disease.

Paget's Disease of the Scrotum

The Key Features

  • Foreign cells in the epidermis;

  • PAS-D +, mucicarmine +;

  • Intra-epidermal apocrine origin: GCDFP15+, CK7+, CEA+, EMA+, CK20-;

  • Association with underlying adenocarcinoma: especially CK20+ or CA19-9+.
CLINICAL FEATURES
 
  • Eczematoid, red, pruritic, slow-growing;
  • Extramammary locations: axilla, labia majora, scrotum, perineum;
GROSS FINDINGS
 
  • Circinate, annular, erythematous, eczematoid plaque
MICROSCOPIC FINDINGS
 
  • Foreign epithelioid cells in the epidermis just above the basal layer; in single, in rows, small nests/clusters, or gladular;
  • Often see a cleft-like separation between the Paget's cells and the adjacent normal epithelial cells;
  • Tumor cells are round or oval with pale, amphophilic cytoplasm that is commonly vacuolated;
  • Nuclei contain dispersed or vesicular chromatin;
  • The involved epidermis commonly exhibits hyperkeratosis and acanthosis that mimics SCC.
DIFFERENTIAL DIAGNOSES
 
  • Superficial spreading melanoma: S100+;
  • Bowenoid intraepidermal SCC: CK7-.
IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS
 
  • Intra-epidermal apocrine origin: GCDFP-15 +, CK7+, CEA+, EMA;
  • If CA19-9 or CK20+, should rule out association with adenocarcinoma in the rectum, urinary bladder, or endocervix;
  • Positive for PAS-D, mucicarmine and Alcian blue in 50-60% cases;
TREATMENT AND PROGNOSIS
 
  • Surgical resection but may be very difficult.
REFERENCES
 
  • AFIP, nonmelanocytic tumors of the skin, series 4;
  • Rosai and Ackerman's Surgical Pathology, 9th edition.