Rare Palatal Cribriform Adenocarcinoma of the Salivary Glands: a Case Report

Introduction:

Cribriform adenocarcinoma of the salivary glands (CASG) is a rare tumor (<1% of salivary gland tumors). It typically affects patients in their fifth to sixth decades of life, with no gender predilection. The tongue is the most common site, although other locations such as the palate, tonsil, retromolar region and upper lip have been reported. CASG mainly metastasizes to regional lymph nodes.

Case report:

A 64-year-old patient with a history of ischemic heart disease presented with a progressively enlarging palatal swelling over two years.
Oral examination revealed a well-circumscribed 3 cm mass of the soft palate. Cervical computed tomography showed a palatal mass measuring 18 × 14 mm, without local invasion or cervical lymphadenopathy. A biopsy was performed.

Results:

Histologically, the lesion showed a lobulated carcinomatous proliferation composed of solid nests and cribriform structures separated by fibrous septa.
Tumor cells displayed moderate atypia, with vesicular, optically clear nuclei, peripheral nucleoli, minimal mitotic activity and eosinophilic cytoplasm. Immunohistochemistry revealed positivity for CK7 and S100, focal CK5/6 expression, and negativity for CK20 and p63.

These findings were consistent with CASG. The patient subsequently underwent surgical excision.

Discussion:

CASG is currently considered a variant of polymorphous adenocarcinoma (WHO 5th edition). Histologically, it shows cribriform or solid architecture, sometimes with glomeruloid features. Cellular atypia is usually mild, with nuclei resembling those of papillary thyroid carcinoma.
The differential diagnosis includes polymorphous adenocarcinoma, papillary thyroid carcinoma and adenoid cystic carcinoma.
Treatment of CASG is primarily surgical excision, with optional cervical lymph node dissection or radiotherapy. Despite regional metastasis, prognosis remains excellent.

Conclusion:

CASG is a rare, low-grade malignancy, considered a variant of polymorphous adenocarcinoma. Palatal localization is less common, and the tumor shares cytological features with papillary thyroid carcinoma. Prognosis remains favorable, even in the presence of cervical lymph node metastasis.