Distinctive Pattern of Glial Fibrillary Acidic Protein Immunoreactivity Useful in Distinguishing Fragmented Pleomorphic Adenoma, Canalicular Adenoma and Polymorphous Low Grade Adenocarcinoma of Minor Salivary Glands

Department of Diagnostic Sciences, Division of Oral and Maxillofacial Pathology, University of North Carolina School of Dentistry, Chapel Hill, NC 27599, USA.
Head and Neck Pathology 09/2007; 1(1):27-32. DOI: 10.1007/s12105-007-0003-8
Source: PubMed

ABSTRACT Immunohistochemistry (IHC) can be helpful in the diagnosis of minor salivary gland neoplasms including those that have been incisionally biopsied or fragmented during surgery that do not contain key diagnostic features on hematoxylin and eosin sections. IHC has been used as an adjunct to distinguish among many salivary gland neoplasms using both qualitative and quantitative methods. The objective of this study was to determine whether a distinctive immunoreactivity staining pattern to GFAP can be consistently observed among three selected minor salivary gland neoplasms and thus serve as a diagnostic adjunctive procedure.
Glial fibrillary acidic protein (GFAP) reactivity was examined among 78 minor salivary gland neoplasms: 27 canalicular adenomas (CAA), 21 pleomorphic adenomas (PA) and 30 polymorphous low grade adenocarcinomas (PLGA). Each case was evaluated by two oral and maxillofacial pathologists (OMP) blinded to the diagnosis. Consensus was reached on the pattern of GFAP reactivity among the neoplastic cells and on the similarities and differences among the cases.
Ninety-six percent (96%) of CAAs demonstrated a distinctive linear immunoreactive pattern among cells in proximity to connective tissue interface. All (100%) PAs demonstrated diffuse immunopositivity within tumor cells. All (100%) PLGAs showed little or no intralesional reactivity and no peripheral linear immunoreactivity. Additional challenge cases were examined by outside OMPs to demonstrate the utility of these findings.
This study demonstrates that the pattern of GFAP immunoreactivity may be an adjunct to diagnosis among PA, CAA and PLGA. The pattern of distinctly linear GFAP immunoreactivity at the tumor/connective tissue interface in CAA has not been reported previously. This distinctive feature may permit the pathologist to differentiate among CAA, PA and PLGA when an incisional biopsy and/or fragmentation cause key diagnostic features to be absent. Because each of these neoplasms requires a different treatment approach, this can be of major significance.

Download full-text


Available from: Valerie A Murrah, Jun 17, 2015
126 Reads
  • Source
    • "Multiple studies have been performed to investigate the role of immunomarkers in salivary gland tumors. A large number of studies have evaluated the role of CD 117 (c-kit) and smooth muscle actin (SMA) in differentiating AdCC from PLGA [13–17], while glial fibrillary acidic protein (GFAP) seems promising in differentiating between PA and PLGA [12, 18–20]. In salivary gland pathology, lot many antibodies have been applied to analyse different tumor cell types in order to establish differences among tumor types and highly variable results have been reported. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To study the immunohistochemical pattern of CD 117, glial fibrillary acidic protein (GFAP), smooth muscle actin (SMA) and CD 43 in pleomorphic adenoma (PA), adenoid cystic carcinoma (AdCC) and polymorphous low grade adenocarcinoma (PLGA) of minor salivary glands. Materials and Methods: Twenty cases of PA, 20 cases of AdCC and 10 cases of PLGA were retrieved from record files along with their paraffin blocks at Armed Forces Institute of Pathology, Pakistan. New histological diagnosis was made on freshly prepared H&E sections followed by application and analysis of immunostains. Results: The mean age of the patients was 44 ± 15 (mean SD) (range; 17–86) years. There were 26 male and 24 female patients with a male to female ratio of 1.08:1. Fourteen cases of PA, 14 cases of AdCC and 6 cases of PLGA were positive for CD117. In case of GFAP, only 9 cases of AdCC and 3 cases of PLGA were positive; however, 16 cases of PA were also positive. Twelve cases of AdCC and 7 cases of PA were positive for SMA and half of the PLGA cases were also reactive. Nonetheless, the least expression was seen in case of CD 43, where only five cases of AdCC were positive. Six cases of PA and three cases of PLGA were also positive. Conclusion: Our results suggest that the use of GFAP, SMA, CD 117 and CD 43 as an adjunct to histological examination is not helpful in differentiating PA, AdCC and PLGA from one another.
    01/2014; 11(1):38-46.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Salivary gland tumors are relatively uncommon and there exists a considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants, in addition to overlapping histological patterns similar to those observed in different tumor entities. The classification is complex, but is closely relevant to the prognostic and therapeutic aspects. Although hematoxylin-eosin staining is still the gold standard method used for the diagnosis, immunohistochemistry (IHC) can enhance the accuracy and be a helpful tool when in cases to investigate the subjects that cannot be assessed by histological examination, such as the cell nature and differentiation status, cell proliferation, and tumor protein expression. This review depicts on the practical diagnostic utility of IHC in salivary gland tumor pathology under the following issues: assessment of cell differentiation, focusing on neoplastic myoepithelial cells; discrimination of histologically mimic tumor groups; diagnosis of specific tumor types, e.g., pleomorphic adenoma, adenoid cystic carcinoma, and salivary duct carcinoma; and evaluation of malignancy and prognostic factors. IHC plays a limited, even though important, role in the diagnosis of salivary gland tumors, but is often useful to support the histological assessment. However, unfortunately few tumor type-specific markers are still currently available. For these reasons, IHC should be considered a method that can be used to assist the final diagnosis, and its results themselves do not directly indicate a definitive diagnosis.
    Acta histochemica et cytochemica official journal of the Japan Society of Histochemistry and Cytochemistry 10/2012; 45(5):269-82. DOI:10.1267/ahc.12019 · 1.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Malignant salivary gland neoplasms are rare, representing approximately 3% to 7% of all head and neck cancers. Contrasting from the more common mucosal head and neck cancers, which, in general, are ascribed to excessive tobacco, alcohol use, and more recently to viral infection, specific carcinogenic factors for malignant salivary gland growths have not been as clearly identified. Histologically, they represent a heterogeneous group of tumors. Forty histologic types of epithelial tumors of the salivary glands have been reported; some are exceedingly rare and may be the topic of only a few case reports. Salivary tumors can arise in the major salivary glands or in one of the minor salivary glands (predominantly mucus secreting glands), which are distributed throughout the upper aerodigestive. Most patients who develop malignant salivary gland tumors are in the sixth or seventh decade of life. FNA should be considered as part of the diagnostic evaluation but due to its varying sensitivities and specificities imaging modalities such as ultrasound, CT scans, and MRI should also be used as diagnostic adjuncts. Surgery is the primary modality for management of these tumors, nontraditional surgical approaches and instrumentation, as well as facial nerve monitoring, can be selectively utilized to try and decrease the morbidity associated with these surgical procedures. Adjuvant treatment is primarily achieved with radiation therapy. Chemotherapy continues to have a palliative role in the management of salivary gland tumors; however, research in this field is trying to identify a therapeutic role for chemotherapy in order to improve overall survival. Keywords: Salivary Gland Tumors, Epidemiology of Salivary Gland Tumors, Types of Salivary Gland Tumors, Diagnosis and Treatment of Salivary Gland Tumors
    Cancer treatment and research 08/2013; 1(1):8-24. DOI:10.11648/j.jctr.20130101.12
Show more