Salivary duct carcinoma

Salivary duct carcinoma
Diagnosis in short

Salivary duct carcinoma, abbreviated SDC, is a rare salivary gland tumour that typically has an aggressive course.

General

• Malignant counterpart of salivary duct adenoma.
• Male:female ~= 4:1.
• Dismal prognosis.
• Typically >50 years old.
• Mostly in the parotid.

Microscopic

Features - resembles ductal breast carcinoma:

• Architecture: sheets, nests, cords, cribriform, micropapillary.
• Neoplastic cells line-up around cystic spaces "Roman bridges".
• Nuclear atypia (variation in size, shape, staining).
• Apocrine snouts - pseudopod-like/lollipop-like undulations of the cell membrane.
• Decapitation secretions - apocrine snouts (membrane bound blobs of cytoplasm) that have separated from its mother cell.

Notes:

• Similar to ductal breast carcinoma - key to remember.

DDx:

• Carcinoma ex pleomorphic adenoma with SDC component.

Images

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  SDC - very low mag. (WC/Nephron)

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  SDC - low mag. (WC/Nephron)

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  SDC - intermed. mag. (WC/Nephron)

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  SDC - high mag. (WC/Nephron)

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  SDC - very high mag. (WC/Nephron)

• 

  SDC - low mag. (WC/Nephron)

• 

  SDC - intermed. mag. (WC/Nephron)

www:

• Salivary duct carcinoma (webpathology.com).

Subtypes

• Conventional.
• Mucinous - worse prognosis; opposite of what would one expect from the outcomes in breast cancer.
• Micropapillary - assoc. with a poor prognosis.
• Sarcomatoid/spindle cell.

IHC

• LMWK, EMA, CK7, CK19 +ve.
• p63 -ve.
• Androgen receptor +ve.
• BRST2 (GCDFP-15) +ve.
• HER2 +ve ~21%; use of trastuzumab (Herceptin) not systematically studied.

Curiosity:

• PSA +/-.
• PSAP +/-.
• ER-beta +ve.
• ER-alpha -ve (the common ER stain).

See also

• Salivary glands.