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salivary duct carcinoma

Monday 8 March 2004

SDC

Definition: Salivary duct carcinoma (SDC) is an aggressive adenocarcinoma of the salivary glands associated with poor clinical outcome.

Images

- salivary duct carcinoma

- SDC diagnostic algorythm

Salivary duct carcinoma (SDCa) is a high grade malignant neoplasm arising from the excretory ducts of salivary gland and represents less than 10% of all salivary gland malignancies. It is more common in males than females and affects sixth through eighth decades of life. It most commonly affects Stenson’s duct within parotid gland; other sites of involvement include submandibular gland, minor salivary glands and rarely sublingual gland, larynx and paranasal sinuses. It often presents as a rapidly enlarging parotid mass with or without pain and facial nerve involvement.

Macroscopy

Grossly, salivary duct carcinoma presents as a poorly circumscribed, infiltrative mass with variable size (1-10 cm). The cut surface is tan white to gray-yellow with solid and cystic areas.

Microscopy

Histologically, SDCa resembles ductal carcinoma of breast and may appear as intraductal or infiltrating neoplasm. Variety of growth patterns can be seen, including cell nests, lobules with comedo-type necrosis, solid, cribriform, cystic and papillary.

The tumor cells are large polygonal with hyperchromatic nuclei, prominent nucleoli and abundant eosinophilic cytoplasm. Increased mitotic activity and marked nuclear pleomorphism are usually present.

Morphologic features frequently noted in the invasive areas include absence of myoepithelial layer, large cystic foci, stromal fibrosis, absence of normal salivary parenchyma within neoplastic foci, angioinvasion, perineural invasion, and invasion of surrounding soft tissues.

In addition to many growth patterns seen with salivary duct carcinoma, there are a number of histologic variants, including sarcomatoid, micropapillary, mucin rich, oncocytic, osteoclast like giant cell, and high grade in-situ variant. Hybrid tumors with multiple histologic types within a given tumor are not uncommon.

Immunochemistry

Salivary gland carcinomas are positive for CK7, EMA, CEA, and GATA-3 (nuclear staining). GCDFP-15 is focally positive. They are also HER-2, EGFR, and androgen receptor positive while ER and PR are negative. The Ki-67 proliferation index is usually high.

- 98% of salivary duct carcinomas are apocrine/androgen receptor positive ( AR+ )

Differential diagnosis

Differential diagnosis of salivary duct carcinoma includes :
- high grade mucoepidermoid carcinom a,
- adenoid cystic carcinoma ,
- acinic cell carcinoma ,
- oncocytic carcinoma ,
- metastatic mammary carcinoma .

Molecular biology

A variety of molecular and genetic rearrangements have been described in salivary duct carcinomas.

Most important are LOH in chromosome 9p21, 6q, 16q, 17p, 17q and HER-2 gene amplification (up to 36% cases). Frequently TP53 gene mutation and deletion of PTEN are also found.

- SDCs are known to carry TP53 mutations in about 50%, however, only little is known about alternative pathogenic mechanisms within the p53 regulatory network.

- 12q13-15 amplification
- Subgroups of SDCs display genomic amplifications of MDM2 and/or CDK4 , partly in association with TP53 mutations and rearrangement/amplification of HMGA2.

- PLAG1 rearrangements (27379604, 23738717)

- HMGA2 rearrangements (27379604, 23738717)

See also

- salivary gland tumors

Open references

- Clinicopathological features and treatment outcomes of the rare, salivary duct carcinoma of parotid gland. Al-Qahtani KH, Tunio MA, Bayoumi Y, Gurusamy VM, Bahamdain FA, Fatani H. J Otolaryngol Head Neck Surg. 2016 May 16;45(1):32. doi : 10.1186/s40463-016-0146-2 PMID: 27184361 (Free)

- Salivary duct carcinoma: A clinopathological report of 11 cases. Huang X, Hao J, Chen S, Deng R. Oncol Lett. 2015 Jul;10(1):337-341. PMID: 26171026 (Free)

Paywall references

- Subsets of salivary duct carcinoma defined by morphologic evidence of pleomorphic adenoma, PLAG1 or HMGA2 rearrangements, and common genetic alterations.
Chiosea SI, Thompson LD, Weinreb I, Bauman JE, Mahaffey AM, Miller C, Ferris RL, Gooding WE.
Cancer. 2016 Oct 15;122(20):3136-3144. doi : 10.1002/cncr.30179
PMID: 27379604

- An analysis of PLAG1 and HMGA2 rearrangements in salivary duct carcinoma and examination of the role of precursor lesions.
Bahrami A, Perez-Ordonez B, Dalton JD, Weinreb I.
Histopathology. 2013 Aug;63(2):250-62. doi : 10.1111/his.12152
PMID: 23738717

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