Metastasizing pleomorphic adenoma: a fascinating enigma

Pleomorphic Adenoma of the Submandibular Gland with Skull Metastasis: A Case Report

Metastasizing pleomorphic adenoma is a rare entity that has the propensity for distant metastasis despite being histologically benign. We report the case of a 56-year-old woman with a long-standing right upper neck swelling and a recent-onset swelling over the left side of the scalp. Clinical workup did not reveal any other tumor deposits in the body. Complete excision of the right submandibular gland and the scalp swelling was performed. The case was diagnosed as metastasizing pleomorphic adenoma. The exact cause of the malignant manifestation of this histologically benign entity is unclear. The time of appearance of a metastatic deposit is highly variable and is usually preceded by a local recurrence. Further research on the malignant behavior of this entity is warranted.

Clinical and Morphological Aspects of Aggressive Salivary Gland Mixed Tumors: A Narrative Review

Salivary gland tumors are a rare and heterogeneous group of neoplasms of the head and neck region. The mixed category of these tumors include the following entities: pleomorphic adenoma (PA), carcinoma ex pleomorphic adenoma (CEPA), salivary carcinosarcoma (CS), and metastasizing PA (MPA). The most common benign tumor of the salivary glands is PA. Metastasis and malignant degeneration have been reported in cases of PA of a salivary gland origin. Judging by their behavior, MPA, CEPA, and CS can be considered aggressive tumors. Invasive CEPA has been identified in the parotid gland more frequently. MPA and CS cases reported in the current literature are rare. In this paper, we present, narratively, the clinico-morphological features of this group of mixed tumors.

Pathogenesis Analysis of Salivary Gland Tumors Through the Expression of Programmed Death-Ligand 1 (PD-L1)

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm, followed by Warthin's tumor (WT). In addition to its high frequency, PA also shows metastasis and transformation towards malignancy as carcinoma ex-pleomorphic adenoma (CXPA). While the histogenesis of WT remains unclear, especially given the presence of lymphoid stroma around the developing tumor and the immunological interaction between them. Immune escape is a carcinogenesis mechanism of tumors to avoid the host immune system by producing PD-L1. This study was conducted to determine whether there is an immune escape through the expression of PD-L1 in salivary gland tumors. The tissue sections of PA, CXPA, and WT were stained with Hematoxylin Eosin and immunostained with a rabbit monoclonal recombinant anti-PD-L1 antibody. We observed immunopositive PD-L1 on the cell membrane with or without cytoplasm staining. PA and CXPA expressed PD-L1, accompanied by an anomaly expression of CXPA in several spots at the salivary gland at the surgical border. Therefore, PD-L1 is one of the PA pathways to transform into CXPA through immune escape. WT expressed PD-L1 in the cytoplasm and lymphoid stroma but not on the cell membrane. It is interpreted as positive constitutive, which may have the function of increasing tumor cell growth, while overexpressed PD-L1 in lymphoid stroma is thought to be associated with a poor prognosis of the tumor and is suspected to transform into malignancy, such as B-cell Lymphoma.

CD24-gold nanocomposite as promising and sensitive biomarker for cancer stem cells in salivary gland tumors

Cancer stem cells are highly tumorigenic cells in the majority of the tumor that are responsible for the initiation, rapid growth, invasion, metastasis, and therapeutic resistance associated with various human cancers. The aim of this project is to assess a diagnostic and prognostic biomarker for the detection of cancer stem cells in salivary gland tumors using gold nanoparticles that are synthesized and conjugated to CD24 primer to form a CD24-Gold Nanocomposite. Sixty cases were included (29 pleomorphic adenoma, 19 carcinoma ex pleomorphic adenoma, and 12 normal controls). Alterations in biomarker expression between studied groups were analyzed and correlated with clinicopathological characteristics using Fisher's exact and Chi-square tests. ROC and Kaplan-Meier curves were used to validate diagnostic and prognostic values, respectively. This study confirms that CD24-Gold Nanocomposite served as a promising and highly sensitive biomarker in salivary gland tumor diagnosis and prognosis prediction.

Maxillofacial diagnostic features of the enigmatic metastasizing pleomorphic adenoma

Considering the confusion in the literature regarding local recurrence, spread, or metastases of pleomorphic adenoma (PA) in the head and neck region, the aim of this study was to enhance understanding of the characteristics of metastasizing pleomorphic adenoma (MPA) by reviewing the literature and presenting a case. English language articles with proof of metastases were included in the literature review. Of the 80 cases in the literature with MPA, 46 were female and 33 were male (sex missing for one case). Thirty-five percent of the neoplasms affected the bones; the maxilla was affected in five cases and the mandible in three. The parotid was the primary site in 72.5% of cases and the submandibular gland in 16.2% of cases. The local recurrence rate was 70%. The mean interval between primary PA and MPA was 15.52 years. The total mortality rate was 8.7%. A case of PA of the submandibular gland that recurred after surgical excision and metastasized (confirmed by the presence of intact cortical borders) to the ipsilateral mandibular body, upper lip, and neck is described. The high mortality rate in a histologically defined benign disease that metastasizes demands that management include careful primary excision and long-term clinical follow-up.

A new ligand of CD105 screened out by phage display technology provides a reliable identification of recurrent or metastasizing pleomorphic adenoma from pleomorphic adenoma

OBJECTIVES

To assess CD105 expression in pleomorphic adenoma (PA), recurrent pleomorphic adenoma (RPA) and metastasizing pleomorphic adenoma (MPA), to identify new epitopes and screen a ligand with high affinity to CD105 by phage display technology, to evaluate the reliability of the new ligand for identifying RPA/MPA from PA.

METHODS

Phage display technology was used to screen ligands with high affinity to recombinant human CD105. The ligand with strongest affinity to CD105 was synthesized by FMOC Chemistry according to the sequencing results. The archived formalin fixed paraffin-embedded (FFPE) tissues of 35 PA cases, 12 RPA cases and 2 MPA cases were sliced and immunofluorescent stained. CD105 expression were detected by Confocal laser scanning microscopy (CLSM). The relative fluorescence intensity was calculated with the image processing software Image J. Statistical analyses were performed by the software Graph Pad Prism (Version 7.0a). Using PROC logistic, receiver operating characteristic (ROC) curves, area under ROC curves (AUCs) were generated to assess the sensitivity and specificity of the new ligand for identifying RPA/MPA from PA cases.

RESULTS

A ligand with specialty and high affinity to CD105 i.e. ligand nABPK296 were developed. FITC-labeled ligand nABPK296 confirmed the difference of CD105 expression in RPA/MPA and PA. The AUC of nABPK296 was 0.9418.

CONCLUSIONS

CD105 is a promising biomarker for identification of RPA/MPA from PA cases. Ligand nABPK296 provides a promising approach to CD105 detection. This study also validated the reliability of phage display technology in finding new episodes and ligands with high affinity for antigens.

Metastasising Pleomorphic Salivary Adenoma: A Rare Case Report of a Massive Untreated Minor Salivary Gland Pleomorphic Adenoma with Concurrent Ipsilateral Cervical Node Metastases

Salivary gland tumours constitute approximately 1-5% of all human neoplasms. Pleomorphic adenoma (PA) is the commonest benign neoplasm affecting the parotid gland most often (> 75%), followed by the submandibular gland (13%), then the palate (9%). Metastasising pleomorphic adenoma (MPA) is extremely rare. The effects can be severe and a reported 40% of MPA patients die with disease. This case represents the first known case in English literature of an untreated minor salivary gland PSA of the palate metastasising to an ipsilateral cervical node. We report a 61 year old female who presented with a large tumour occupying the palatal vault, and cervical neck mass. The oral tumour was believed to have been growing over four decades. The patient died eight months following surgical resection. Of known cases, male: female ratio is 35:51 and the mean age at diagnosis is 49.2. Most commonly, MPA is detected in bone 33.3% (n = 29), lung 31% (n = 27) and cervical lymph nodes 20.7% (n = 18). Thorough reporting is deemed essential to further understand the biological differences of non metastasising and metastasising PAs, treatment outcomes, prognosis and survival rates.

Pleomorphic Adenoma Originating from Heterotopic Salivary Tissue of the Upper Neck: A Diagnostic Pitfall

Pleomorphic adenoma directly arising in the neck is thought to originate from heterotopic salivary gland tissue. In this article, we present the case of a 55-year-old female patient with a histologically proven pleomorphic adenoma located at the left mandibular angle, anteriorly to the sternocleidomastoid muscle and posteroinferiorly to the submandibular gland. As the patient also had an ipsilateral thyroid nodule with coarse calcifications, clinical and radiological features suggested a possible level II metastatic lymph node. However, ultrasound-guided fine needle aspiration cytology and postsurgery histopathological examination revealed a pleomorphic adenoma arising from heterotopic salivary gland tissue unrelated to a benign thyroid nodule. In this article, we provide a review of the existing literature on heterotopic salivary gland tissue and related neoplasms and discuss their imaging presentation.

Brain metastasis of carcinoma ex pleomorphic adenoma of the parotid gland: case report and review of the literature

We present an extremely infrequent case of brain metastasis of a parotid tumor. To our knowledge, this is the second case reported of a brain metastasis of a malignant parotid tumor, carcinoma ex pleomorphic adenoma. Pleomorphic adenoma represents 60% of tumors of the parotid gland, and although it is a benign tumor, it can transform into carcinoma ex pleomorphic adenoma in 5% of cases, one of the most aggressive neoplasms of the salivary glands. We want to note the need for an accurate diagnostic. Thanks to aggressive surgical management, our patient survived more than 1½ years.

Pleomorphic Adenoma in Subcutaneous Plane of the Neck: A Rare Entity

Heterotopic Salivary Gland Tissue (HSGT) is salivary tissue found in locations not normally host to it. Neoplasms occurring in these heterotopic tissues are very rare. Review of literature has revealed the neck to be host to HSGT and rarely, tumourigenic changes in these inclusions have been observed. We present a clinically unsuspected case of an ectopic pleomorphic adenoma of lower neck in which the ectopic salivary tissue was found in subcutaneous plane, which to the best of our knowledge has not been reported and was proved only on cytology and histopathology. There is a probability of this tumour undergoing malignant transformation. Therefore, these tumours need to be promptly diagnosed, adequately treated and should be included in the differential diagnosis of neck masses.

Genomic copy number alterations of primary and secondary metastasizing pleomorphic adenomas

AIMS

Metastasizing pleomorphic adenoma (MPA) is a rare tumour, and its mechanism of metastasis still is unknown. To date, there has been no study on MPA genomics. We analysed primary and secondary MPAs with array comparative genomic hybridization to identify somatic copy number alterations and affected genes.

METHODS AND RESULTS

Tumour DNA samples from primary (parotid salivary gland) and secondary (scalp skin) MPAs were subjected to array comparative genomic hybridization investigation, and the data were analysed with NEXUS COPY NUMBER DISCOVERY. The primary MPA showed copy number losses affecting 3p22.2p14.3 and 19p13.3p123, and a complex pattern of four different deletions at chromosome 6. The 3p deletion encompassed several genes: CTNNB1, SETD2, BAP1, and PBRM1, among others. The secondary MPA showed a genomic profile similar to that of the primary MPA, with acquisition of additional copy number changes affecting 9p24.3p13.1 (loss), 19q11q13.43 (gain), and 22q11.1q13.33 (gain).

CONCLUSION

Our findings indicated a clonal origin of the secondary MPA, as both tumours shared a common profile of genomic copy number alterations. Furthermore, we were able to detect in the primary tumour a specific pattern of copy number alterations that could explain the metastasizing characteristic, whereas the secondary MPA showed a more unbalanced genome.