Table 1

Differential diagnosis of juvenile pleomorphic adenoma of the cheek

Tumor

Salient histological features


Carcinoma ex pleomorphic adenoma


Adenoid cystic carcinoma

- Cribriform and pseudoglandular patterns of basaloid cells with hyalinized stroma

- Frequent perineural invasion

- Minimal nuclear pleomorphism

- No squamous differentiation

- No high grade dysplasia or squamous carcinoma in situ, no extensive necrosis


Polymorphous low grade adenocarcinoma

- Uniform plump columnar cells with bland nuclei arranged in variable growth patterns (tubular, cribriform, papillary, solid, fascicular, microcystic, single file, pseudoadenoid cystic, strand-like, mixed)

- Perineural invasion common around small nerves

- Infiltrative borders


Basal cell adenoma

- Elongated and branching canaliculi separated by hyaline stroma


Acinic cell carcinoma

- Variable cell types (serous, clear, vacuolated, intercalated duct cells) arranged in solid, microcystic, papillary cystic and follicular patterns

- few mitotic figures


Clear cell carcinoma-hyalinizing type

-Trabeculae, cords, islands or nests of monomorphic clear cells surrounded by hyalinized bands with foci of myxohyaline stroma


Cystadenocarcinoma

- Invasive, cystic growth pattern, 75% had

- Conspicuous papillary component

- Composed of small cuboidal cells, large cuboidal cells, tall columnar cells or mixture

- Cystic spaces with hemorrhage and granulation tissue are frequent


Intraductal carcinoma

- intraductal neoplasm with micropapillary, cribriform, solid, comedo or clinging patterns, with preservation of myoepithelial cells surrounding intraductal tumor

Mucoepidermoid carcinoma

- Cords, sheets, clusters of mucous, squamous, intermediate and clear cells; low to high grade

Epithelial myoepithelial carcinoma

- Both epithelial and myoepithelial components seen

- Most tumor cells have myoepithelial features with clear cytoplasm or naked nuclei

- Focally, there are ducts or tubules with an outer rim of myoepithelial cells and inner, dark ductal cells with scant eosinophilic cytoplasm and round, bland nuclei


Dalati and Hussein Diagnostic Pathology 2009 4:32   doi:10.1186/1746-1596-4-32

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