Polymorphous adenocarcinoma of the oral cavity: A skeptical case mimicking lobular carcinoma of breast and gastric carcinoma

Abstract

Polymorphous adenocarcinoma (PAC) is a distinctive salivary gland neoplasm that predominantly occurs in the minor salivary glands. The tumor is characterized by cytological uniformity, morphological diversity, an infiltrative growth pattern and low metastatic potential. It presents as an asymptomatic, slow- growing mass within the oral cavity. This salivary gland tumor is difficult to diagnose both clinically and histopathologically due to its indolent presentation and diverse architectural pattern which includes various microscopic patterns namely- solid, ductal-tubular, cribriform, trabecular and single-file growth. Hence, Immunohistochemistry plays a very important role in diagnosing this tumor. We hereby report a rare case of PAC occurring in a 50yr old female patient presenting with a lesion in right upper posterior part of alveolus extending to the hard palate.

Keywords: Immunohistochemical analysis; Indian file pattern; polymorphous low-grade adenocarcinoma.

Figure 1

Intraoral photograph showing an erythematous swelling

Figure 2

Fine needle aspiration cytology showing epithelial cells with hyperchromatic nuclei and abundant eosinophilic cytoplasm suggestive of malignant neoplastic cells (×10)

Figure 3

Section showing intact surface epithelium of stratified squamous variety (H&E, ×10)

Figure 4

Section showing individual tumor cells in single file pattern (H&E, ×10)

Figure 5

Section showing minor salivary glands (H&E, ×10)

Figure 6

Section showing perineural invasion (H&E, ×40)

Figure 7

Picture on the lesional tissue (isomorphic small tumor islands) that helped us to identify it as polymorphous low-grade adenocarcinoma other than the single file pattern (×40)

Figure 8

Section of the lesion stained with carcinoembryonic antigen showing strong positivity for tumor cells (×10)

Figure 9

Immunohistochemical stain showed E-cadherin positivity (×10)

Figure 10

Section of the lesion stained with vimentin showing strong positivity for tumor cells (×10)

Figure 11

Section of the lesion stained with cytokeratin 7 showing strong positivity for tumor cells (×10)

Figure 12

Histopathological picture of the recurrent lesion in the same site after surgery (×10)

Figure 13

Clinical picture of recurrent lesion