**DENT4217** **Diseases of the salivary glands** **Histopathology Lab** A/Prof Omar Kujan UWA Dental School # **Diseases of the salivary glands** ## **Histopathology Lab** Slide ID 753 Histological section showing tissue architecture with glandular structures and stromal components, stained with hematoxylin and eosin. Histological section showing tissue with varying cellular density and staining, likely depicting a pathological or anatomical structure with connective tissue and possible inflammatory infiltrate. Slide ID 753 - Mucocele is defined as a mucus-filled cyst that may appear in the oral cavity, gall bladder, paranasal sinuses, or lacrimal sac. - Mucocele forms because of salivary gland **mucous** extravasation or **retention** and is usually related to trauma in the area of the lower **lips**. Salivary duct cyst, however, is a type of **mucous retention cyst** which is almost never located on the lower **lip**. # **Mucocele (Slide ID 753)** - Mucocele is defined as a mucus-filled cyst that may appear in the oral cavity, gall bladder, paranasal sinuses, or lacrimal sac. - It is a benign, mucus-containing cystic lesion of the minor salivary gland. - Mucocele forms because of salivary gland **mucous** extravasation or **retention** and is usually related to trauma in the area of the lower **lips**. - It occurs either due to rupture of salivary gland duct or by blockade of salivary gland duct. - The more common type is a mucus extravasation cyst; the other is a mucus retention cyst. - Salivary duct cyst, however, is a type of **mucous retention cyst** which is almost never located on the lower **lip**. Close-up of oral mucosa showing a raised, smooth, dome-shaped lesion on the inner cheek, with surrounding erythema and visible vasculature. **Mucocele** - A mucocele is a benign, mucus-containing cystic lesion of the minor salivary gland. - The more common is a mucus extravasation cyst; the other is a mucus retention cyst. - Mucocele occurs either due to rupture of salivary gland duct or by blockade of salivary gland duct. Slide title with no additional content Histological section showing tissue with pink and purple staining, likely representing connective tissue and cellular components under microscopic examination. Histological slide showing tissue with pink and purple staining, likely H&E, indicating cellular and extracellular matrix structures. Histological slide showing glandular structures with surrounding stroma, stained with hematoxylin and eosin. Histopathological image showing glandular structures with varying sizes, surrounded by stromal tissue, stained with hematoxylin and eosin. Slide ID 756 - **Necrotizing sialometaplasia** is a benign, self-limiting inflammatory reaction of salivary gland tissue which may mimic squamous cell carcinoma or mucoepidermoid carcinoma, both clinically and histologically, that creates diagnostic dilemma leading to unwarranted aggressive surgery. # **Necrotizing Sialometaplasia (Slide ID 756)** - **Necrotizing sialometaplasia** is a benign, self-limiting inflammatory reaction of salivary gland tissue which may mimic squamous cell carcinoma or mucoepidermoid carcinoma, both clinically and histologically, that creates diagnostic dilemma leading to unwarranted aggressive surgery. Oral cavity showing teeth with discoloration and a lesion on the tongue. - Necrotizing sialometaplasia (NS) was first reported by Abrams et al in the year 1973. - This condition has been described as non-neoplastic inflammatory salivary gland disease and benign, self-limiting, reactive inflammatory disorder of salivary tissue. - NS can resemble a malignancy and its misdiagnosis has resulted in unnecessary radical surgery. https://onlinelibrary.wiley.com/doi/full/10.1002/ccr3.3931 **Necrotizing Sialometaplasia** - Necrotizing sialometaplasia (NS) was first reported by Abrams et al in the year 1973 - This condition has been described as non-neoplastic inflammatory salivary gland disease and benign, self-limiting, reactive inflammatory disorder of salivary tissue. - NS can resemble a malignancy and its misdiagnosis has resulted in unnecessary radical surgery https://onlinelibrary.wiley.com/doi/full/10.1002/ccr3.3931 Slide title with no additional content Histological slide showing a tissue sample with pink and purple staining, likely representing cellular and extracellular structures under microscopic examination. Microscopic histological image showing tissue with pink and purple staining, likely representing cellular structures and extracellular matrix. Histological section showing glandular structures with stromal tissue, likely from a tissue biopsy stained with H&E. Histological section showing glandular structures with epithelial cells and stromal tissue, stained with H&E. **Pleomorphic adenoma** - Typically has 3 components: - Epithelial (ductal) component forming the inner layer of cysts and tubules - Myoepithelial cells as the outer layer of cysts and tubules and scattered within the myxoid stroma - Cytology of myoepithelial cells can be plasmacytoid, spindled, epithelioid, clear or stellate shaped - Stromal component is typically myxoid, chondroid or myxochondroid - It can also be hyalinized or fibrotic - Metaplastic changes may be seen, e.g. adipose metaplasia, osseous metaplasia, squamous metaplasia (sometimes with keratinization), sebaceous metaplasia and mucinous metaplasia # **Pleomorphic Adenoma (Slide ID 764)** - Also called benign mixed tumor. - Most common tumor of salivary glands. - It is a painless, slow growing tumor, composed of biphasic population of epithelial and mesenchymal cells. - Typically has 3 components: - Epithelial (ductal) component forming the inner layer of cysts and tubules - Myoepithelial cells as the outer layer of cysts and tubules and scattered within the myxoid stroma - Cytology of myoepithelial cells can be plasmacytoid, spindled, epithelioid, clear or stellate shaped - Stromal component is typically myxoid, chondroid or myxochondroid - It can also be hyalinized or fibrotic - Metaplastic changes may be seen, e.g. adipose metaplasia, osseous metaplasia, squamous metaplasia (sometimes with keratinization), sebaceous metaplasia and mucinous metaplasia. Slide ID 764 - **Pleomorphic adenoma** - Most common tumor of salivary glands - Painless, slow growing tumor, composed of biphasic population of epithelial and mesenchymal cells - Also called benign mixed tumor Figure showing facial swelling in an elderly patient from multiple angles, with marked areas indicating regions of interest. Slide title with no additional content Histopathological slide showing tissue with varying staining patterns, including purple and red areas, indicative of cellular structures and possible pathological changes. Histological section showing adipose tissue with embedded cells and vascular structures, stained with hematoxylin and eosin. Histological image showing perineural and intraneural invasion, with stained tissue revealing cellular structures and nerve involvement. **Microscopic description** - Cribriform, solid or tubular pattern similar to cylindroma of skin - Small bland myoepithelial cells with scant cytoplasm and dark compact angular nuclei surround pseudoglandular spaces with PAS+ excess basement membrane material and mucin - Peripheral perineurial invasion and small true glandular lumina - No squamous differentiation, no extensive necrosis # **Adenoid Cystic Carcinoma (Slide ID 769)** - Deceptively benign histologic appearance and cribriform, solid or tubular pattern similar to cylindroma of skin ([Arch Pathol Lab Med 2011;135:511](Arch Pathol Lab Med 2011;135:511)). - Most common in submandibular, sublingual or minor salivary glands. - Also seen in nose, sinus, upper airway. - 22% of salivary gland malignancies. ## **Microscopic description** - Cribriform, solid or tubular pattern similar to cylindroma of skin. - Small bland myoepithelial cells with scant cytoplasm and dark compact angular nuclei surround pseudoglandular spaces with PAS+ excess basement membrane material and mucin. - Peripheral perineurial invasion and small true glandular lumina. - No squamous differentiation, no extensive necrosis. Slide ID 769 - **Adenoid Cystic carcinoma** - Deceptively benign histologic appearance and cribriform, solid or tubular pattern similar to cylindroma of skin ([Arch Pathol Lab Med 2011;135:511](Arch Pathol Lab Med 2011;135:511)) - Most common in submandibular, sublingual or minor salivary glands – Also seen in nose, sinus, upper airway - 22% of salivary gland malignancies **Clinical features** - Occurs in fifth to sixth decades - Male predominance - Slow growing, indolent but aggressive - Recurrences are frequent - Often late and difficult to predict - Rarely lymph node metastases - 5 year survival is 60%, 10 year is 30%, 15 year is 15% ## **Clinical features** - Occurs in fifth to sixth decades. - Male predominance. - Slow growing, indolent but aggressive. - Recurrences are frequent. - Often late and difficult to predict. - Rarely lymph node metastases. - 5 year survival is 60%, 10 year is 30%, 15 year is 15%. Slide title with ID number Microscopic view of tissue with pink and white staining, showing cellular structures and possible pathological changes. Histological slide showing tissue with pink and purple staining, likely representing connective tissue and cellular structures under microscopic examination. **Microscopic description** - Cords, sheets and clusters of mucous, squamous, intermediate and clear cells - Low to high grade, although even high grade tumors lack marked nuclear atypia, frequent mitotic figures or extensive necrosis - Occasional focal sebaceous cells, goblet type cells, oncocytic change, inflammatory reaction to extravasated mucin or keratin - No squamous cell carcinoma in situ - Low grade: mucinous and intermediate cells with bland nuclei form glandular spaces - High grade: solid and infiltrative growth pattern of atypical epidermoid and intermediate cells with cytoplasmic clearing and small number of mucinous cells; < 20% intracystic component # **Mucoepidermoid Carcinoma (Slide ID 770)** - 2/3 occur in parotid gland; also in palate. - Wide age range, mean 49 years, range 15 - 86 years, no gender predominance. - Low grade: 15% recur, 5 year survival 90 - 98%, usually stage I. - High grade: 25% recur, 5 year survival 50 - 56%, deaths usually within first 5 years. *(Am J Surg Pathol 2001;25:835)* ## **Microscopic description** - Cords, sheets and clusters of mucous, squamous, intermediate and clear cells. - Low to high grade, although even high grade tumors lack marked nuclear atypia, frequent mitotic figures or extensive necrosis. - Occasional focal sebaceous cells, goblet type cells, oncocytic change, inflammatory reaction to extravasated mucin or keratin. - No squamous cell carcinoma in situ. - Low grade: mucinous and intermediate cells with bland nuclei form glandular spaces. - High grade: solid and infiltrative growth pattern of atypical epidermoid and intermediate cells with cytoplasmic clearing and small number of mucinous cells; < 20% intracystic component. Histological section showing tissue with three labeled arrows: yellow, red, and green, indicating specific cellular or structural features. Slide ID 770 - **Mucoepidermoid carcinoma** - 2/3 occur in parotid gland; also in palate - Wide age range, mean 49 years, range 15 - 86 years, no gender predominance - Low grade: 15% recur, 5 year survival 90 - 98%, usually stage I - High grade: 25% recur, 5 year survival 50 - 56%, deaths usually within first 5 years *(Am J Surg Pathol 2001;25:835)* Oral cavity with lesion on the palate indicated by arrow Image with unreadable or placeholder text (?????) 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