Oral and Maxillofacial Pathology
Polymorphous low-grade adenocarcinoma versus pleomorphic adenoma of minor salivary glands: Resolution of a diagnostic dilemma by immunohistochemical analysis with glial fibrillary acidic protein

This paper was previously presented in abstract form: Curran A, White D, Damm D, Murrah V. The utility of glial fibrillary acid protein expression as a strong diagnostic adjunct in differentiating polymorphous low grade adenocarcinoma from pleomorphic adenoma. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:187.
https://doi.org/10.1067/moe.2001.111306Get rights and content

Abstract

Objectives: Differentiating polymorphous low-grade adenocarcinoma (PLGA) from pleomorphic adenoma (PA) in salivary gland biopsy specimens from the palatal region might be a diagnostic dilemma for the pathologist when tumors are cellular with minimal matrix material. Glial fibrillary acidic protein (GFAP), expressed by a number of cells in the mature central nervous system, is also expressed in tumors not generally considered to be of glial origin. PAs have previously been reported to strongly express GFAP. PLGAs have been examined for the expression of this protein only in small group studies with variable results. The objective of this study was to determine whether differential expression of GFAP in these 2 tumors could be diagnostically significant. Study Design: A total of 42 PLGAs and 36 PAs, formalin-fixed and paraffin-embedded, were immunostained with rabbit polyclonal antibodies to GFAP. CNS tissue was used as a positive control. Results: Results showed the 36 cases of PA to be strongly positive for GFAP. Of PLGAs, 31 were negative and 11 showed faint patchy reactivity in luminal cells. Conclusions: The results strongly support a role for GFAP as a diagnostic adjunct in the microscopic differential diagnosis of PLGA versus PA. This study is the largest investigation with consistent results to date addressing the application of this antibody to the diagnostic problem of PA versus PLGA. (ORAL Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:194-9)

Section snippets

Material and methods

Minor salivary gland tumors originally diagnosed and coded as PLGA by oral pathologists at Emory University Hospital Division of Oral, Head, and Neck Pathology, the Emory University Hospital and the University of Kentucky Oral Pathology Biopsy Services, were retrieved. Adequate tissue was available on 42 tumors. For comparison, 36 tumors previously diagnosed and coded as pleomorphic adenomas of the minor salivary gland also were retrieved and studied similarly. New sections were cut from

Results

Available clinical information on cases used in this study is presented in Table III.

. Clinical data

Pleomorphic adenomas (N = 36)
 Sex
  Men11
  Women25
 Age range15-76
  Mean40.3
 Location
  Hard palate15
  Buccal mucosa8
  Labial mucosa4
  Soft palate4
  Unstated3
Polymorphous low grade adenocarcinomas (N = 42)
 Sex
  Men14
  Women20
  Unstated8
 Age range39-81
 Mean61.5
 Location
  Hard palate10
  Palate8
  Soft palate6
  Junction of hard/soft palate4
  Buccal mucosa3
  Upper lip1
  Maxillary vestibule1
  Unstated9
Classical histopathologic features of PA and PLGA

Discussion

Histopathologic features of PA and PLGA are known to overlap, particularly on the palate, causing a diagnostic dilemma for the pathologist. All the following conditions can result in potential diagnostic dilemmas for the pathologist attempting to differentiate these two lesions in the minor salivary glands:

  • 1.

    Unencapsulated palatal PAs without matrix (Fig 5)

  • 2.

    Incisional biopsy resulting in the absence of an overall diagnostic architectural pattern (Fig 6)

  • 3.

    Curetted fragments resulting in absence of an

References (22)

  • R Haba et al.

    Polymorphous low grade adenocarcinoma of submandibular gland origin

    Acta Pathol Japan

    (1993)
  • Cited by (40)

    • Salivary GFAP as a potential biomarker for diagnosis of mild cognitive impairment and Alzheimer's disease and its correlation with neuroinflammation and apoptosis

      2021, Journal of Neuroimmunology
      Citation Excerpt :

      To the best of our knowledge, GFAP levels in saliva of AD or MCI patients have not been reported before. However, salivary GFAP levels have been previously referenced for patients suffering from oral cancer (Curran et al., 2001; Huang et al., 1996; Li et al., 2009). Both ELISA and Dot Blot analysis proved, in a similar accuracy, that GFAP levels can differentiate cognitively healthy individuals from patients with either MCI or AD, as well as MCI patients from AD patients.

    • Polymorphous adenocarcinoma of the sublingual gland: A case report and literature review

      2021, Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology
      Citation Excerpt :

      Thus far, several genes related to PAC have been reported. Of note, PRKD1-3 mutation [48–50], cytokeratins (AE1/AE3, 34bE12, CK1, CK7, pan CK, and CAM5.2) [29,32,51–55], β-catenin [56], EMA [50–52], S-100 [29,30,32,50,51,54], vimentin [24,32], c-kit [57], osteopontin [58], bcl-2 [29,55], α-SMA [59], p53 [29], p63 [59], CEA [60], GFAP [33], actin [33] and galectin-3 [61] show high expression in PLGA; GFAP [51], p53 [55], cyclin D1 [55] and CK20 [53] show low expression in PAC. While some reports distinguish other SGTs, such as ACC and pleomorphic adenoma (PA), some controversies remain.

    • Salivary Glands

      2020, Gnepp's Diagnostic Surgical Pathology of the Head and Neck, Third Edition
    • Malignant Neoplasms of the Salivary Glands

      2019, Head and Neck Pathology: A Volume in the Series: Foundations in Diagnostic Pathology
    • Malignant neoplasms of the salivary glands

      2012, Head and Neck Pathology: Second Edition
    View all citing articles on Scopus

    Reprint requests: Alice E. Curran, DMD, MS, Department of Diagnostic Sciences, University of Mississippi School of Dentistry, 2550 N State St, Jackson, MS 39216, [email protected]

    View full text