Salivary glands
Primary salivary gland neoplasms
Malignant
Acinic cell carcinoma
Authors: F. Zahra Aly, M.D., Ph.D., Jen-Fan Hang, M.D.
Topic Completed: 1 August 2011
Minor changes: 5 January 2021
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Acinic cell carcinoma[TI] salivary[TI]
Table of Contents
Definition / general | Poor prognostic factors | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Electron microscopy description | Differential diagnosisCite this page: Aly FZ, Hang JF. Acinic cell carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/salivaryglandsaciniccell.html. Accessed January 19th, 2021.
Definition / general
- 1 - 3% of all salivary gland tumors; 3% of all parotid salivary gland tumors
- #2 childhood salivary gland malignancy after mucoepidermoid carcinoma
- Usually parotid and minor salivary glands, also parotid lymph nodes
- 10 - 15% metastasize (usually to local lymph nodes), 10 - 30% recur (may be due to inadequate excision)
- 80 - 90% recur if incompletely excised
- 5 year survival 90%, 20 year survival 60%
- Less aggressive in minor salivary glands
Poor prognostic factors
- High stage, pain or fixation, gross invasion, desmoplasia, anaplasia or dedifferentiated component, increased mitotic figures, necrosis, neural invasion, incomplete resection, large size, involvement of deep lobe of parotid, multinodularity
Case reports
- 16 year old girl with parotid mass (Case #355)
- 35 year old father and 16 year old daughter with parotid tumors (Arch Pathol Lab Med 1999;123:1118)
- 42 year old man with dedifferentiated parotid tumor with facial nerve involvement but no prior surgery (Arch Pathol Lab Med 2004;128:e52)
- 67 year old woman with dedifferentiation with myoepithelial features after multiple resections (Arch Pathol Lab Med 2002;126:1104)
- Elderly patient with mass behind ear representing metastatic tumor (Case #183)
Gross description
- Encapsulated, tanish gray, firm to soft, solid / cystic; usually < 3 cm
- 3% bilateral or multicentric
Microscopic (histologic) description
- At scanning power, basophillia and prominent lymphoid infiltrate should raise suspicion of acinic cell carcinoma
- Tumor shows multidirectional differentiation towards acinar, ductal as well as myoepithelial elements
- Some tumor cells must demonstrate differentiation towards acinar cells
- Variable patterns: solid, microcystic, papillary cystic (associated with hemorrhage), follicular
- Variable cell types: uniform acinar (serous) type cells with basophilic granular cytoplasm, clear cells (hypernephroid pattern, contains glycogen or mucin), vacuolated, intercalated duct, nonspecific glandular cells (smaller, syncytial)
- Few mitotic figures
- May have prominent lymphoid follicles at periphery (lymphoid stroma), psammoma bodie
Microscopic (histologic) images
Case #355
Various images
Cytology description
- Sheets or loosely cohesive cells without regular acinar organization
- Plump tumor cells with abundant granular to vacuolated cytoplasm, indistinct cell borders and variable zymogen secretory granules best seen on Romanowsky type stain
- Minimal nuclear atypia and frequent naked nuclei
Cytology images
Contributed by Jen-Fan Hang, M.D.
Loose clusters
Intracytoplasmic
zymogen granules
Case #355
Various images
Positive stains
- Keratin, alpha-1-antichymotrypsin, alpha amylase; also vasoactive intestinal polypeptide, myoepithelial markers, granules are PAS+ diastase resistant
- SOX10 and DOG1 (complete membranous pattern)
- May have focal neuroendocrine staining
Electron microscopy description
- Multiple round, electron flocculent material with variable granule density (dependent on fixation), cytoplasmic secretory granules
Differential diagnosis
- Normal parotid gland: tumors lack striated and interlobular ducts, lack lobular architecture
- Thyroid carcinoma
