Epithelial Membrane Antigen (EMA)

• EMA expression with membranous staining pattern in Malignant Extra-Renal Rhabdoid Tumor (MERT).
• EMA expression in apocrine metaplasia of the breast. Note the prominent staining on the apical membrane of the cells.
• EMA expression in apocrine metaplasia of the breast.
• EMA expression in a cutaneous meningioma.
• EMA expression in a cutaneous meningioma.
• EMA expression in distal convoluted renal tubules.
• EMA expression in a myoepithelioma.
• EMA expression in plasma cells.
• EMA expression in plasma cells.
• EMA expression in plasma cells.
• EMA expression in plasma cells.
• EMA expression in a normal sebaceous gland. The epidermis is negative.
• EMA expression in eccrine glands. Note that the nerve in the center also shows staining of the perineurium.

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Synonyms

• MUC1
• CD227

Antibodies

• MA695
• E29

Expression in Normal Tissues

• nearly all apical surfaces of ductular and glandular epithelium
• normal plasma cells are often EMA positive
• renal distal convoluted tubules
• renal collecting ducts
• perineural cells

Expression in Neoplastic Entities

Benign

Tumor name	% Positive Staining (Sensitivity)	Number of Cases	Specificity	Comments
Meningioma	100%	22
Perineurioma

Intermediate/Uncertain Malignant Potential

Tumor name	% Positive Staining (Sensitivity)	Number of Cases	Specificity	Comments

Malignant

Tumor name	% Positive Staining (Sensitivity)	Number of Cases	Specificity	Comments
Epithelioid sarcoma	85%	20
Synovial Sarcoma	91%	23
Low Grade Fibromyxoid Sarcoma

Pertinent Negatives

The antigen is typically NOT expressed in the following:

• Schwannoma

Practical Uses / Panels

• EMA may be useful if pancytokeratin is negative in a suspected synovial sarcoma, as it is more sensitive than cytokeratin in this setting.