Acinic cell carcinoma
| Acinic cell carcinoma | |
|---|---|
| Other names | Acinic cell adenocarcinoma, Acinar cell carcinoma |
| Micrograph of an acinic cell carcinoma (right of image) and acinar glands (parotid gland - left of image). H&E stain. | |
| Pronunciation |
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| Specialty | ENT surgery, Oncology, Oral and maxillofacial pathology |
| Symptoms | Slow-growing, painless mass in parotid region, occasional pain/tenderness (30-50%), facial nerve involvement (5-10%) |
| Complications | Recurrence (10-35%), metastasis (5-10%), high-grade transformation, facial nerve dysfunction |
| Usual onset | Any age; peak in 5th decade |
| Duration | Chronic |
| Types | Solid, microcystic, papillary-cystic, follicular |
| Causes | NR4A3 overexpression (80%), radiation exposure, genomic rearrangements |
| Risk factors | Prior radiation exposure, radioactive isotope exposure, certain chemical exposures, possible familial predisposition |
| Diagnostic method | Clinical examination, imaging (MRI/CT), fine needle aspiration, histopathology, immunohistochemistry |
| Differential diagnosis | Pleomorphic adenoma, Warthin tumor, mucoepidermoid carcinoma, secretory carcinoma, oncocytoma |
| Prevention | Avoiding radiation exposure |
| Treatment | Surgical resection, radiation therapy for high-risk cases |
| Medication | Chemotherapy for recurrent/metastatic disease |
| Prognosis | Excellent; 5-year survival 90-97% for localized disease; 10-year survival 88-94% |
| Frequency | 6-15% of all salivary gland malignancies; 0.13 cases per 100,000 annually |
| Deaths | Low mortality; significantly higher with high-grade transformation or distant metastasis |
Acinic cell carcinoma is a malignant epithelial neoplasm that shows differentiation toward serous acinar cells of salivary gland origin. First described by Godwin et al. in 1954, it represents approximately 6-15% of all salivary gland malignancies, making it the third most common after mucoepidermoid carcinoma and adenoid cystic carcinoma.[1]
Approximately 80-90% of acinic cell carcinomas arise in the parotid gland, with the remainder occurring in the submandibular gland and minor salivary glands, particularly those of the buccal mucosa and palate.[2] Rare cases have been reported in ectopic salivary gland tissue and in non-salivary sites including the breast, pancreas, and lung.[3]
Clinically, acinic cell carcinoma typically presents as a slow-growing, painless mass. The disease has a generally favorable prognosis, with 5-year survival rates exceeding 90% for localized disease, though recurrences can develop even decades after initial treatment.[4] While traditionally considered a low-grade malignancy, recent molecular and clinical studies have revealed significant heterogeneity, with a subset of tumors demonstrating high-grade transformation and more aggressive behavior.[5]
Historically, acinic cell carcinoma was classified among the "adenomas" until the 1950s, when its malignant potential was recognized. The World Health Organization officially reclassified it as a malignant epithelial neoplasm in 1972, acknowledging its capacity for local invasion, recurrence, and metastasis.[6] In 2017, the WHO classification further refined the understanding of this entity, distinguishing it from the newly described mammary analogue secretory carcinoma (MASC), which shares some morphological features but has distinct molecular characteristics.[7]
Molecularly, acinic cell carcinoma is characterized by the overexpression of the nuclear receptor NR4A3 in approximately 80% of cases, resulting from genomic rearrangements at chromosome 9q31.[8] Treatment typically involves complete surgical excision, with adjuvant radiation therapy reserved for cases with adverse features such as positive margins, high-grade histology, or regional metastasis.
- ^ Godwin JT, Foote FW Jr, Frazell EL (1954). "Acinic cell adenocarcinoma of the parotid gland; report of twenty-seven cases". American Journal of Pathology. 30 (3): 465–477. PMC 1942372. PMID 13158491.
- ^ El-Naggar AK, Chan JK, Grandis JR, Takata T, Slootweg PJ, eds. (2017). WHO Classification of Head and Neck Tumours. Vol. 9. International Agency for Research on Cancer. pp. 173–174.
- ^ Thompson LD (November 2010). "Salivary gland acinic cell carcinoma". Ear, Nose, & Throat Journal. 89 (11): 530–532. doi:10.1177/014556131008901115. PMID 21086763.
- ^ Vander Poorten V, Triantafyllou A, Thompson LD, et al. (November 2016). "Salivary acinic cell carcinoma: reappraisal and update". European Archives of Oto-Rhino-Laryngology. 273 (11): 3511–3531. doi:10.1007/s00405-015-3855-7. PMID 26833208.
- ^ Skálová A, Sima R, Vanecek T, et al. (August 2009). "Acinic cell carcinoma with high-grade transformation: a report of 9 cases with immunohistochemical study and analysis of TP53 and HER-2/neu genes". American Journal of Surgical Pathology. 33 (8): 1137–1145. doi:10.1097/PAS.0b013e3181a38e1c. PMID 19461508.
- ^ Batsakis JG, Luna MA, el-Naggar AK (November 1990). "Histopathologic grading of salivary gland neoplasms: II. Acinic cell carcinomas". Annals of Otology, Rhinology, and Laryngology. 99 (11): 929–933. doi:10.1177/000348949009901116. PMID 2173659.
- ^ Skalova A (July 2013). "Mammary analogue secretory carcinoma of salivary gland origin: an update and expanded morphologic and immunohistochemical spectrum of recently described entity". Head and Neck Pathology. 7 (Suppl 1): S30 – S36. doi:10.1007/s12105-013-0455-y. PMC 3712090. PMID 23821214.
- ^ Haller F, Bieg M, Will R, et al. (January 2019). "Enhancer hijacking activates oncogenic transcription factor NR4A3 in acinic cell carcinomas of the salivary glands". Nature Communications. 10 (1): 368. doi:10.1038/s41467-018-08069-x. PMC 6341117. PMID 30664632.