A 41-year-old woman with no significant medical history presented with complaints of a mass “on her right jaw” and partial paralysis of the right side of her face. The patient reported that she had noticed the mass several months earlier and that it had slowly increased in size and become mildly tender. Her symptoms of facial paralysis, which had begun 1 week earlier, had prompted her to seek medical attention. Physical examination revealed a firm mass in the region of the right parotid gland that extended under the angle of the mandible. Imaging studies showed an ill-defined mass involving the right parotid gland and extending along the right facial nerve. Fine-needle aspiration and core biopsies of the mass were nondiagnostic, showing extensive fibrosis and rare atypical cells with hyperchromatic nuclei and irregular nuclear borders. Excision of the mass including a right parotidectomy was performed, and sacrifice of the cervical branch of the right facial nerve was necessary. Gross examination of the right parotidectomy surgical specimen revealed a 2.7-cm firm, vaguely nodular white mass with irregular borders that extended to the surgical margin of resection. Histologic analysis revealed variably sized, cystic, well-circumscribed nodules of neoplastic cells that exhibited a central cribriform pattern (Figure 1) and occasional central necrosis. The neoplastic cells appeared to be oncocytic with ample eosinophilic cytoplasm and round nuclei having prominent central nucleoli (Figure 2). Irregular nests and cords of neoplastic cells were also identified infiltrating the adjacent tissue, which was markedly fibrotic (Figure 3). A prominent perineural extension was also present (Figure 4). The nonneoplastic parotid tissue was unremarkable except for an extensive lymphoplasmacytic inflammatory infiltrate. A metastatic neoplasm was identified in one lymph node adjacent to the right parotid gland.

What is your diagnosis?

Salivary duct carcinoma is an uncommon tumor of the salivary glands that has a histologic appearance remarkably similar to both the in situ and infiltrating components of ductal carcinoma of the breast. First reported in 1968 by Kleinsasser et al,1 this neoplasm has been described in the major and minor salivary glands but occurs most commonly in the parotid gland (86% of cases). The lesion may arise de novo or as the malignant epithelial component of a carcinoma ex pleomorphic adenoma.2 Clinically, salivary duct carcinomas show a gender predilection, occurring 3 times more commonly in men than in women. The occurrence of salivary duct carcinoma peaks in the sixth and seventh decades of life, but the tumor has been documented in patients from 22 to 91 years of age.3 These tumors present as slowly to rapidly enlarging masses that are variably painful. Facial nerve involvement by a tumor with associated paralysis may be a presenting clinical feature.

Grossly, salivary duct carcinomas are white-tan masses that can reach several centimeters in size. The cut surface of these tumors may be solid and homogeneous or may contain cystic areas filled with serous fluid or necrotic tumors. Microscopically, the tumor may assume any of the histologic patterns seen in its breast counterpart. Intraductal foci within the tumor may have papillary, cribriform, or solid patterns. Comedonecrosis is frequently seen. Infiltrating ductal carcinomas may form small solid nests, attenuated ductal structures, or cords of cells in a desmoplastic stroma. The tumor cells vary from relatively large cells with irregular nuclei and prominent nucleoli to smaller monotonous cells with hyperchromatic nuclei. Perineural invasion is frequently seen.4 Immunohistochemically, the vast majority of salivary duct carcinomas exhibit epithelial membrane antigen, cytokeratin, and carcinoembryonic antigen expression,5 but unlike their counterparts in the breast, estrogen and progesterone receptor expression is seen only rarely.6 HER-2/neu overexpression as well as expression of androgen receptors have been documented in these tumors.7,8 

The differential diagnosis of this lesion includes metastatic carcinoma as well as other primary salivary gland neoplasms such as polymorphous low-grade carcinoma, oncocytic adenocarcinoma, mucoepidermoid carcinoma, and adenocarcinoma not otherwise specified. Surgical excision of the tumor with regional lymph node sampling and then postoperative irradiation is the most effective therapy.9 The effectiveness of antiandrogens and herceptin as adjuvant treatment options has yet to be proven.

Unfortunately, salivary duct carcinoma is an aggressive lesion, with regional lymph node metastasis present at the time of resection in 40% of the patients. In the series reported by Lewis et al,5 35% of the patients eventually showed local recurrence, and distant metastasis, primarily to the lung and bone, occurred in 62% of the patients. The prognosis for patients with this tumor is poor, with 65% of the patients dying between 5 months and 10 years after the diagnosis—most within 5 years.

The patient in this case underwent radiation therapy after attempted surgical resection of her tumor, and 1 year later, she is alive with no evidence of local recurrence or distant metastasis.

Kleinsasser
,
O.
,
H. J.
Klein
, and
G.
Hubner
.
Salivary duct carcinoma: a group of salivary gland tumors analogous to mammary duct carcinoma.
Arch Klin Exp Ohren Nasen Kehlkopjheilkd
1968
.
192
:
100
105
.
Olsen
,
K. D.
and
J. E.
Lewis
.
Carcinoma ex pleomorphic adenoma: a clinicopathologic review.
Head Neck
2001
.
23
:
705
712
.
Ellis
,
G. L.
and
P. L.
Auclair
.
Tumors of the Salivary Glands.
Washington, DC: Armed Forces Institute of Pathology; 1996:325. Atlas of Tumor Pathology; 3rd series, fascicle 17
.
Kumar
,
R. V.
,
L.
Kirn
, and
A. K.
Bhargava
.
et al
.
Salivary duct carcinoma.
J Surg Oncol
1993
.
54
:
193
198
.
Lewis
,
J. E.
,
B. C.
McKinney
, and
L. H.
Weiland
.
et al
.
Salivary duct carcinoma: clinicopathologic and immunohistochemical review of 26 cases.
Cancer
1996
.
77
:
223
230
.
Fan
,
C. Y.
and
E. L.
Barnes
.
Expression of androgen receptor and prostatic specific markers in salivary duct carcinoma: an immunohistochemical analysis of 13 cases and review of the literature.
Am J Surg Pathol
2000
.
24
:
579
586
.
Skalova
,
A.
,
V.
Kucerova
, and
P.
Szepe
.
et al
.
Salivary duct carcinoma—a highly aggressive salivary gland tumor with HER-2/neu oncoprotein overexpression.
Pathol Res Pract
2001
.
197
:
621
626
.
Kapadia
,
S. B.
and
L.
Bames
.
Expression of androgen receptor, gross cystic disease fluid protein, and CD44 in salivary duct carcinoma.
Mod Pathol
1998
.
11
:
1033
1038
.
Colmenero
,
R. C.
,
R. M.
Patron
, and
P.
Martin
.
Salivary duct carcinoma: a report of nine cases.
J Oral Maxillofac Surg
1993
.
51
:
641
646
.

Author notes

Corresponding author: Ozlem Ulusarac, MD, Department of Pathology, USA Medical Center, 2451 Fillingim St, Mobile, AL 36617 ([email protected])