Pleomorphic adenoma histology, parotid salivary gland, examined by bright-field microscopy on Hematoxylin and Eosin stained sections. Imaging modality: Light microscopy; technique: Hematoxylin and Eosin staining. The sample reveals a classic biphasic neoplasm comprising epithelial ductal structures and myoepithelial cells embedded in an abundant stromal backdrop. Epithelial components form cords, ducts, and small island formations lined by cuboidal to columnar cells with eosinophilic cytoplasm and hyperchromatic nuclei. Intermixed myoepithelial cells display plasmacytoid or spindle morphologies, often surrounding epithelial elements. The stroma is a prominent feature, ranging from basophilic, myxoid to more eosinophilic, hyalinized areas. The myxoid matrix is rich in glycosaminoglycans and imparts a loose, gelatinous appearance, while hyalinized zones contribute dense eosinophilic bands. Overall architecture is often well circumscribed with minimal pleomorphism and low mitotic activity, consistent with benign behavior. Clinical significance includes differentiation from malignant salivary tumors; prognosis is favorable with complete surgical excision. Differential considerations include mucoepidermoid carcinoma, adenoid cystic carcinoma, basal cell adenoma, and Warthin tumor. This image is useful for educational purposes in pathology, otolaryngology, and head-and-neck surgery, illustrating quintessential pleomorphic adenoma features: epithelial and myoepithelial proliferation in a chondromyxoid stroma, with duct-like structures and a variable stromal composition. This histologic pattern aids diagnosis and education.

Histology of a pleomorphic adenoma involving the parotid gland. This light-microscopy image derives from a hematoxylin and eosin–stained paraffin section. It demonstrates a biphasic neoplasm with epithelial ductal–acinar elements embedded in a myxoid to chondromyxoid stroma. Epithelial components arrange as trabeculae, tubules, and duct-like acini, often lined by a two-layered cast: inner cuboidal to columnar luminal cells and outer basal/myoepithelial cells with plasmacytoid or spindle morphology. The surrounding stroma is variably myxoid, sometimes chondroid, producing a lobulated architecture with intimately interwoven cellular and stromal zones. Clefts and interspersed myxoid pools may be evident; ossification or calcifications are occasional. The lesion is typically well circumscribed within the parotid, showing no frank invasion of adjacent parenchyma on histology. Mitotic activity is rare. The overall appearance—myxoid/chondromyxoid matrix with epithelial tubules and ducts—supports pleomorphic adenoma; however, histologic overlap with other salivary gland neoplasms necessitates clinical correlation and, when indicated, ancillary immunohistochemistry (e.g., cytokeratin, S-100, GFAP) or molecular testing. Clinically, pleomorphic adenoma presents as a slow-growing, painless parotid mass in adults, with a favorable prognosis after complete surgical excision, though recurrence and potential for malignant transformation exist if spillage or capsular rupture occurs.

Imaging modality: light microscopy of Hematoxylin and Eosin stained histology section from a salivary gland lesion. Anatomical site: parotid region; histologic plane: peripheral-to-central glandular architecture. The slide reveals classic pleomorphic adenoma features with biphasic tumor components in a variably hyalinized, myxoid stroma. Epithelial nests and anastomosing cords are embedded in a chondromyxoid matrix, while duct-like tubules are evident in places. In the lower-right field, small nests and cords form an Indian file pattern, illustrating cellular diversity within a single tumor. The left third shows compressed and distorted tubular structures amid dense stromal hyalinization, contributing to a mosaic of microarchitectures. The myoepithelial element contributes spindle- to plasmacytoid cells with variable cytoplasmic appearance; the overall cytology lacks significant atypia or invasion. Clinically, these features correlate with a slow-growing, painless parotid mass and favorable prognosis after complete excision. Diagnostic significance rests on recognizing both epithelial and myoepithelial components within a mucoid to cartilaginous stroma, and on identifying variant patterns to avoid misclassification as malignant salivary neoplasms. Differential diagnoses include adenoid cystic carcinoma, mucoepidermoid carcinoma, and basal cell adenoma; accurate histologic interpretation guides management and recurrence risk assessment. Awareness of this histologic diversity improves diagnostic accuracy and informs surgical planning.

Histology image of a salivary gland tumor demonstrating classic pleomorphic adenoma (mixed tumor). Prepared as a hematoxylin and eosin stained slide and evaluated under light microscopy. The specimen represents salivary gland tissue in the parotid region. Epithelial elements are organized into small nests and rudimentary tubular structures, reflecting ductal differentiation. These epithelial components are embedded in a substantial myxoid background with scattered chondromyxoid areas. Myoepithelial cells contribute to the cellular admixture, accounting for variable cell shapes and occasional plasmacytoid appearances. The stroma ranges from loose, myxoid to more fibrous or hyaline areas, producing a heterogeneous, biphasic architecture typical of pleomorphic adenoma. The overall pattern is benign-appearing with well-demarcated margins in this field; however, the lesion is known for potential recurrence if incompletely excised. Pleomorphic adenoma is a benign salivary gland neoplasm featuring epithelial and myoepithelial components within mucoid and cartilaginous stroma. Diagnostic significance rests on recognizing the biphasic morphology and chondromyxoid matrix, which helps distinguish from malignant mimics such as mucoepidermoid carcinoma or adenoid cystic carcinoma. Clinically, these findings correlate with a slow-growing, painless parotid mass in middle-aged adults. This image is valuable for education, differential diagnosis practice, and radiology-pathology correlation in salivary gland tumors. for clinical education and research.