Source:
BioScience.org – Frontiers in BioScience; Lecture Series

DEFINITION:

  • A neoplastic growth of epithelial cells showing serous acinar differentiation

CLINICAL FEATURES:

  • Occurs most commonly in parotid gland
  • Occurs unilaterally. May occur bilaterally.
  • Occurs more frequently in women than men (3:2)
  • Occurs in young and old individuals
  • Slowly growing, mobile or fixed mass of various durations
  • Asympotatic
  • Pain or tenderness
  • Facial muscle weakness

GROSS FEATURES:

  • Single, well circumscribed to multinodular and ill-defined
  • Firm to cystic
  • 0.5-13 cm
  • Lobular, red to tan cut surface

MICROSCOPIC FEATURES:

  • Patterns
  • Sheets
  • Cysts, some with papillary growth
  • Microcystic
  • Acini
  • Ducts
  • Glands
  • Follicles (similar to thyroid)
  • Epithelium
  • Large polygonal
  • Lightly basophilic cytoplasm
  • Uniform to variable eccentic nuclei

MICROSCOPIC FEATURES:

  • Acinar epithelium
  • Large polygonal
  • Lightly basophilic cytoplasm (blue dot tumors)
  • Protuberance of luminal membrane producing a tombstone appearance
  • Uniform to variable eccentic nuclei
  • Cytoplasmic granules (PAS positive-diastase resistant; mucicarcmine positive)
  • Hemosiderin
  • Duct epithelium
  • Eosinophilic cytoplasm
  • Variable cell size
  • Central lumen of various size

MICROSCOPIC FEATURES:

  • Vacuolated cells
  • Eosinophilic to amphophilic cytoplasm
  • Clear vacuoles
  • PAS and mucicarmine negative
  • Clear cells
  • Lack of glycogen
  • Glandular cells
  • Round to polgonal
  • Eosinophilic to amphophilic cytoplasm
  • Lack of cytoplasmic granules or PAS positivity
  • Nuclear pleomorphism

MICROSCOPIC FEATURES:

  • Vacuolated cells
  • Eosinophilic to amphophilic cytoplasm
  • Clear vacuoles
  • PAS and mucicarmine negative
  • Clear cells
  • Lack of glycogen
  • Glandular cells
  • Round to polgonal
  • Eosinophilic to amphophilic cytoplasm
  • Lack of cytoplasmic granules or PAS positivity
  • Nuclear pleomorphism

MICROSCOPIC FEATURES:

  • Stroma
  • Delicate fibrovascular tissue
  • Collagenous tissue
  • Lymphoid infiltration (in some cases)
  • Hemorrhage
  • Hemosiderin
  • Psammoma bodies

ULTRASTRUCTUAL FEATURES:

  • Main epithelial cells
  • Multiple round, membrane bound, electron dense cytoplasmic granules
  • Vacuoles
  • Lumina
  • Apical junctional complexes
  • Few microvilli
  • Clear cells
  • Dilated ER
  • Lipid inclusions
  • Intracytoplasmic pseudolumina
  • Myoepithelial cells
  • Elongated
  • Microfilaments
  • Dense bodies

    IMMUNOHSITOCHEMICAL FEATURES:
  • Cytokeratin(present)
  • CEA (present)
  • alpha 1 antitrypsin (present)
  • alpha 1 antichymotrypsin (present)
  • Leu-M1 (present)
  • Amylase (present)
  • Transferrin (present)
  • Lactoferrin (present)
  • Vasocactive intestinal polypeptide (present)
  • S-100 (some)
  • GFAP (some)


DIFFERENTIAL DIAGNOSIS:

  • Papillary-cystic and follicular type
  • Cystadenocarcinoma (lack of microcycstic and vacuolated cells)
  • Mucoepidermoid carcinoma (presence of mucous cells)
  • Metastatic thyroid carcinoma (presence of thyroglobulin)
  • Polmorphous low-grade adencarcinoma (perineural invasion, homogeneous cell population, single cell infiltration at the periphery)
 
 

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