Polymorphous low-grade adenocarcinoma of the head and neck

Polymorphous Adenocarcinoma: A Systematic Review of the Literature and Presentation of Two Cases in a Less-Considered Anatomical Site

BACKGROUND

Polymorphous adenocarcinoma (PAC) is the second-most common malignant tumour of the minor salivary glands. Although PAC predominantly affects the palate, it can also involve the buccal mucosa. This systematic review aims to investigate the literature data about PAC. Furthermore, we report two cases of patients affected by PAC in an infrequently considered anatomical site.

METHODS

According to PRISMA guidelines, a systematic review search was conducted on PubMed, Scopus, and Web of Science. Observational studies conducted on patients with a histological diagnosis of PAC were selected and analysed. Furthermore, two cases of patients with PAC affecting the buccal mucosa were reported.

RESULTS

Twenty-nine studies were included, and 143 patients affected by PAC were analysed (62 males, 75 females, and 6 undefined, with a mean age of 57.4 ± 14.5 years). The palate was the most affected site (99/143, 69.2%), followed by the buccal mucosa (12/143, 8.4%). Moreover, we report two cases of patients with PAC affecting the buccal mucosa (one male and one female, with a mean age of 70.5 ± 2.5 years).

CONCLUSIONS

The present study underscores the importance of considering the buccal mucosa as a possible location of minor salivary gland tumours; although it is a less-considered affliction, it is not uncommon.

How Increased Nodal Metastasis and Recurrence in Cribriform Adenocarcinoma Relate to Polymorphous Adenocarcinoma and Survival: A Systematic Review

BACKGROUND

Recently, histologic grade was removed from salivary tumor nomenclature by the WHO to include disease of higher grade. One such entity, cribriform adenocarcinoma (CAC), is an aggressive group of polymorphous adenocarcinoma (PAC), with frequent nodal metastasis and locoregional recurrence. We aim to examine the biologic behavior of this disease as compared with the PAC general cohort inclusive of all subtypes.

METHODS

A systematic review of the literature on polymorphous adenocarcinoma and cribriform adenocarcinoma was completed. A descriptive analysis was performed for the following predictor variables: nodal and distant metastasis, in addition to recurrence. The outcome variables, disease free recurrence, and disease specific survival, where plotted using Kaplan-Meier curves.

RESULTS

PAC and CAC both show median age of diagnosis in the sixth decade of life and a female predominance. CAC occurs most frequently in the tongue and PAC in the palate. The 2 groups show a similar biologic behavior in regards to incidence of distant metastasis (4.1 vs 5.5%), recurrence (12.5 vs 17.8%), and death from disease (3 vs 2.7%). However, there was an increased incidence of nodal metastasis in CAC (53%) as compared with that in PAC of all subtypes (14%).

CONCLUSIONS

CAC exhibits more aggressive biologic behavior as compared with the PAC cohort. Although CAC is not an officially recognized entity, these tumors likely comprise a significant portion of the cases of PAC with poor outcomes and are deserving of attention and consideration for escalation in oncologic treatment.

A contemporary update on hyalinizing clear cell carcinoma: compilation of all in-house cases at our institution and a literature review spanning 2015-2020

Tumors of the head and neck with clear cell features prompt a broad differential diagnosis. A relatively uncommon, but increasingly recognized, entity is hyalinizing clear cell carcinoma (HCCC). This neoplasm, first described in 1994, consists of clear cells arranged in nests or trabecule with a hyalinized stroma. These are low-grade neoplasms that only infrequently metastasize and rarely recur. They also often harbor a unique EWSR-ATF1 gene rearrangement. As the prognosis is excellent compared with other clear cell neoplasms, the correct diagnosis is key. Here we present all of the cases of HCCC in the past decade from our institution alongside a comprehensive literature review spanning 2015-2020 to further characterize this unusual malignancy.

Polymorphous adenocarcinoma: A case report along with its characteristics and diagnostic challenges

Polymorphous adenocarcinoma (PAC) is an uncommon tumor that affects minor salivary glands mainly. It presents as an indolent malignancy that frequently manifests as an asymptomatic, slow-growing mass within the oral cavity, especially palate and its clinical behavior resembles that of benign neoplasm, often causing delay in the diagnosis. Here, we report a rare case of PAC of palate in a 49-year-old female patient along with a concise review of characteristics of PAC and highlight diagnostic challenges caused by the overlap of clinical and microscopic features between PAC, pleomorphic adenoma and adenoid cystic carcinoma.

Utility of p63 and p40 in Distinguishing Polymorphous Adenocarcinoma and Adenoid Cystic Carcinoma

Objective:

Adenoid cystic carcinoma and polymorphous adenocarcinoma are primarily the tumor of minor salivary glands. Both show certain morphological similarities, which limit their proper diagnosis in settings where there are obscuring factors and limited biopsy material. However, there is a considerable difference in treatment and prognosis, which raises the need to distinguish these two entities. In this study, we discuss the utility of two immunohistochemical stains, p63 and p40, in different combinations for distinguishing polymorphous adenocarcinoma from adenoid cystic carcinoma.

Materials and Methods:

Two immunohistochemical stains, p63 and p40, were performed on 47 cases of adenoid cystic carcinoma and 23 cases of polymorphous adenocarcinoma.

Results:

36 out of 47 cases of adenoid cystic carcinoma showed p63+ve/p40+ve immunoprofile, followed by p63-ve/p40-ve immunoprofile, which is seen in10 cases of adenoid cystic carcinoma. However, 22 out of 23 cases of polymorphous adenocarcinoma displayed p63+ve/p40-ve immunoprofile. p63-ve/p40+ve is the least frequent observed immunoprofile, which is seen in only one case of adenoid cystic carcinoma.

Conclusion:

On combining all possible immunoprofile combinations, p63+ve/p40-ve immunoprofile appears to be the most sensitive profile for distinguishing polymorphous adenocarcinoma from adenoid cystic carcinoma.

Role of Antioxidants in Minor Salivary Glands Cancer in the Elderly

BACKGROUND

Minor salivary gland tumors (MSGTs) are infrequent, representing 10% to 15% of all salivary neoplasms. Despite this low frequency, a significant increase in the incidence of these tumors has been reported in the lasts 30 years. While tumors of the salivary glands can appear at any age, different authors consider the peak of incidence to be associated with old age (60+). The etiopathogenesis of MSGTs remains unclear. In this context, the aim of this study was to explore the hypothesis that age-related changes in salivary antioxidant capacity are involved in the pathogenesis of minor salivary glands tumors to identify possible preventive measures.Furthermore the study aimed to describe the clinico-pathological features of a multi-institutional case series of MSGTs which results are consistent with data in the literature.

METHODS

An electronic search of the English language literature was performed using PubMed and Google scholar (<scholar.google.com>). Databases were screened for papers using a number of search strings constructed using relevant terms (minor salivary glands tumors, elderly, diet, antioxidant, saliva, salivary glands).

RESULTS

According to the world literature, the peak of incidence of MSGTs is between the fifth and seventh decades of life. To date, the only confirmed risk factor for salivary gland tumors is the exposure to ionizing radiation. The significantly reduced salivary antioxidant capacity in old people may explain the higher prevalence of these tumors in the elderly population.

CONCLUSIONS

Further investigation is required to determine the real etiopathogenesis of MSGTs and why these tumors result more frequent in elderly patients.

Polymorphous Low-Grade Adenocarcinoma: A Proposed Reconstruction Protocol Based on Past Surgical Experience

BACKGROUND

To propose a reconstructive protocol based on surgical management experience of polymorphous low-grade adenocarcinoma (PLGA) and the location of the primary lesion.

METHODS

Data on the surgical management and the reconstructive technique of 14 histologically conformed patients with PLGA, all treated by the same surgeon, were analyzed and evaluated.

RESULTS

Mean follow-up period in our series was 6.2 years. Mean age at diagnosis was 55.5 years and female to male ratio was 2.2:1. The most common presenting sign was a nonpainful lump or mass in an intraoral location. Most patients were managed by wide local excision and reconstruction method varied from primary closure to the use of radial forearm graft. Recurrence appeared in one of the patients in this series, while 2 required further radiation therapy. A protocol for reconstruction of intraoral patients with PLGA is suggested based on our analysis.

CONCLUSION

Surgical management is the gold standard for PLGA treatment. Neck dissection is recommended only in patients with presurgery fine-needle aspiration confirmed lymph node involvement. The reconstruction depends mainly on location and size of the primary lesion.

Polymorphous adenocarcinoma of the salivary glands: reappraisal and update

Although relatively rare, polymorphous adenocarcinoma (PAC) is likely the second most common malignancy of the minor salivary glands (MiSG). The diagnosis is mainly based on an incisional biopsy. The optimal treatment comprises wide surgical excision, often with adjuvant radiotherapy. In general, PAC has a good prognosis. Previously, PAC was referred to as polymorphous low-grade adenocarcinoma (PLGA), but the new WHO classification of salivary gland tumours has also included under the PAC subheading, the so-called cribriform adenocarcinoma of minor salivary glands (CAMSG). This approach raised controversy, predominantly because of possible differences in clinical behaviour. For example, PLGA (PAC, classical variant) only rarely metastasizes, whereas CAMSG  often shows metastases to the neck lymph nodes. Given the controversy, this review reappraises the definition, epidemiology, clinical presentation, diagnostic work-up, genetics, treatment modalities, and prognosis of PAC of the salivary glands with a particular focus on contrasting differences with CAMSG.

Polymorphous low-grade adenocarcinoma: A Danish national study

OBJECTIVES

To present a national series of polymorphous low-grade adenocarcinoma (PLGA) patients, including survival rates and an analysis of prognostic factors.

MATERIALS AND METHODS

By merging three Danish nationwide registries, 73 patients diagnosed with PLGA from 1990 to 2005 were identified. Histological slides were reviewed and data concerning demographics, tumour site, clinical stage, treatment profiles and follow-up were retrieved. Survival estimates and prognostic factors were evaluated by comparing Kaplan-Meier plots using the Mantel-Haenszel log-rank test.

RESULTS

Of the 73 patients, 47 (64%) were female. Median age was 58years. The most common location was the palate (73%). Median latency was five months. Recurrence was seen in 13% of patients. Overall survival (OS), disease-specific survival (DSS) and recurrence-free survival (RFS) rates after 10years were 73%, 99% and 83%, respectively. Univariate analyses suggested that free resection margins significantly improve RFS.

CONCLUSION

PLGA usually has an excellent survival outcome even in cases of advanced stage disease and locoregional recurrence. Primary choice of treatment should be complete surgical excision. Although there is no convincing evidence for the efficacy of adjuvant radiotherapy, it should still be considered, particularly in cases of involved resection margins and advanced stage disease. Late recurrences are common and respond well to salvage therapy.

Polymorphous low grade adenocarcinoma

Polymorphous low-grade adenocarcinoma (PLGA), is a rare, salivary gland intraoral tumor with complexities in diagnosis and this review highlights the difficulties.

Polymorphous low-grade adenocarcinoma of the tongue base treated by transoral robotic surgery

Polymorphous low-grade adenocarcinoma is a rare malignancy arising from the minor salivary glands in the aerodigestive system, most frequently the hard palate. The treatment of choice is wide surgical resection, and the efficacy of radiotherapy has not been confirmed. A 54-year-old male presenting with a mass at the base of the tongue performed transoral laser microsurgery. The pathologic diagnosis was polymorphous low-grade adenocarcinoma. Complete surgical excision was performed via transoral robotic surgery without a flap reconstruction of the surgical defect. Without complications of bleeding or injury to the hypoglossal nerve, proper surgical margins were obtained, and no recurrence was found after 6 months after surgery. The patient did not complain of dysphagia or aspiration. We conclude that, in surgery for tongue base tumors with unknown malignant potential, transoral robotic surgery can be considered for achieving a definite resection avoiding a mandibulotomy without complications of dysphagia or aspiration after confirmation of malignancy with a frozen biopsy.

Polymorphous Low-Grade Adenocarcinoma of the Palate: A Rare Case Report

Introduction

Polymorphous low-grade adenocarcinoma (PLGA) has been known as a comparatively less aggressive malignant tumor that predominantly occurs in the minor salivary glands. It has presented as a painless, slow growing tumor in the oral cavity. It has been reported to occur rarely in the palate and the prognosis of this lesion is far better than adenocarcinoma as the regional metastasis would be very minimal. A clear difference between the biologic behaviors of adenocarcinoma and PLGA has been reported in literature.

Case Presentation

A 63-year-old female reported at our institute with a swelling in relation to her upper left back region of her jaw for three months, gradual in onset and associated with pain. After clinical and radiological examination, the differential diagnosis were consolidated abscess or minor salivary gland tumor. An incisional biopsy was done and the lesion was diagnosed as PLGA. The lesion was treated by wide excision and reconstruction with immediate obturator. The post-operative follow up showed no evidence of recurrence and the healing was satisfactory.

Conclusions

The site of predilection of PLGA is more in favor of palate (49 - 77.8%) followed by either upper lip or buccal mucosa (7.4 - 13.4%). There are sporadic reports of metastasis sometimes even transformation to a high grade adenocarcinoma, sometimes ending in mortality. Cervical lymph node metastasis is rare with reported incidence of 5 - 15% and is more commonly seen in recurrent tumor than the initial diseases. Extra palatal PLGAs present with significant papillary growth or arising from ventral surface of tongue frequently metastasize to cervical lymph nodes. Distant metastasis is very rare with an incidence of 7.5% and the site involved is the lung which is attributed to the inadequate control of the disease.

Polymorphous low-grade adenocarcinoma of the head and neck

Polymorphous low-grade adenocarcinomas are rare tumors that can arise from many areas of the head and neck. We reviewed the pertinent literature pertaining to the incidence, diagnostic evaluation, and treatment strategies for this malignancy. Histopathologic diagnosis always involves careful analysis of tissue and especially characteristic immunohistochemical staining patterns. Common differential diagnoses include adenoid cystic carcinoma, pleomorphic adenoma, and other benign or malignant salivary gland neoplasms. Although the ideal treatment is debated, surgical resection at times combined with adjuvant radiation therapy is preferred by many physicians. Further research will be needed to delineate optimal management.

Polymorphous Low-Grade Adenocarcinoma (PLGA) in an 18-Year-Old Male

Polymorphous low-grade adenocarcinoma (PLGA) is a minor salivary gland tumor with a low malignant potential. It is twice more common in females, with a mean age of presentation at 59 years. It is a very slow-growing tumor with mean duration of symptoms that range from 27 months to as long as 40 years. We report a case of a male patient who was found to have PLGA with symptoms since birth. The patient was treated with wide local excision with good results. The lip is a rare location for PLGA, and its occurrence in adolescent age groups is even rarer.

Exclusively endoscopic resection of nasopharyngeal adenocarcinoma

We reported two patients with nasopharyngeal adenocarcinoma resected by using the exclusively endoscopic approach. Case reports and a review of the world literature concerning nasopharyngeal adenocarcinoma. The tumors were resected successfully via the exclusively endoscopic approach and no conversions to the conventional approach were necessary. The two patients were followed up for 26 and 18 months respectively, and no recurrence was noted without postoperative chemotherapy or radiotherapy. To the best of our knowledge, this is the first report of endoscopic resection of nasopharyngeal adenocarcinoma. Our experience revealed that not only for the early recurrent nasopharyngeal carcinoma, the exclusively endoscopic nasopharyngectomy can be expanded for the resection of selected nasopharyngeal adenocarcinoma.

Immunohistochemical clue for the histological overlap of salivary adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma

It remains difficult to distinguish adenoid cystic carcinoma (ACC) from polymorphous low-grade adenocarcinoma (PLGA). Although these neoplasms exhibit nearly similar histologic patterns, their biologic behavior is significantly different. This study was carried out in an attempt to overcome the histological overlap between these tumors using immunohistochemical method for c-kit and galectin-3 proteins on twenty cases of salivary gland tumors including twelve ACC and eight PLGA. Results revealed positive cytoplasmic reactivity for c-kit in 100% of ACC cases and only in 25% of PLGA. On the other hand, galectin-3 expression was observed in 100% of both ACC and PLGA cases. Moreover, solid variant of ACC showed overexpression of both proteins than cribriform and tubular subtypes. Significant positive correlation between the two studied proteins in ACC and PLGA was also observed (p < 0.05). Upon these results, over expression of c-kit and galectin-3 in ACC cases supports the concept of solid variant as a high-grade tumor. Moreover, c-kit may be used as a helpful marker to distinguish ACC from PLGA in cases where the diagnosis can be challenging.

Polymorphous low-grade adenocarcinoma: a 17 patient case series

Polymorphous low-grade adenocarcinoma (PLGA) is a rare malignancy most commonly seen in the minor salivary glands. First described in 1983, this entity has been recognized to have an indolent course with rare metastases or deaths. We describe our experience with 17 patients treated at our institution for PLGA from 1984 to 2012. All tumors were located in the oral cavity or soft palate. All patients were treated surgically, with the exception of one patient who declined therapy. No deaths or metastases have been identified in subsequent follow-up. Three patients in this series had undergone prior surgery up to 20 years previously and were treated for recurrences at our institution; no other recurrences have been noted. In summary, PLGA is best treated with wide excision to negative margins with excellent prognosis, but long-term follow-up is recommended given the propensity for late recurrences.

Polymorphous low-grade adenocarcinoma--management and reconstruction with temporalis myofacial flap

Polymorphous low-grade adenocarcinoma is a rare, malignant salivary gland tumor, which is found almost exclusively in minor salivary glands. It is more frequent in the third-seventh decade of life, with a clear female predilection in a 2:1 ratio. It is usually located in the hard or soft palate, although it may be found in the rest of the oral cavity too. It is rare in major salivary glands. In general it has good prognosis, with recurrence rates in the range of 17-24%. Although rare, metastasis to regional lymph nodes has been reported. We report a case of 38 year old female patient who reported with recurrent low grade polymorphous adenocarcinoma in the hard palate, who has been treated with wide excision of the lesion, with reconstruction of the defect using temporalis myofacial flap.

Polymorphous low-grade adenocarcinoma: an analysis of epidemiological studies and hints for pathologists

Background

This study is an analysis of the prevalence of polymorphous low grade adenocarcinoma (PLGA) in epidemiological surveys of salivary tumors published in the English language from 1992 to 2012.

Methods

These surveys included studies from different researchers, countries and continents. The 57 surveys for which it was possible to calculate the percentage of PLGAs among all malignant minor salivary gland tumors (MMSGT) were included in this review.

Results

The statistical analyses show significant differences in the PLGA percentage by time period, country and continent in the studies included in this review. The percentage of PLGAs among MMSGTs varied among the studies, ranging from 0.0% to 46.8%. PLGA rates have varied over the period studied and have most recently increased. The frequency of reported PLGA cases also varied from 0.0% to 24.8% by the country in which the MMSGT studies were performed. The PLGA percentages also varied significantly by continent, with frequencies ranging from 3.9% in Asia to 20.0% in Oceania

Conclusion

Based on these results, we concluded that although the accuracy of PLGA diagnoses has improved, they remain a challenge for pathologists. To facilitate PLGA diagnoses, we have therefore made some suggestions for pathologists regarding tumors composed of single-layer strands of cells that form all of the histological patterns present in the tumor, consistency of the cytological appearance and uniformly positive CK7, vimentin and S100 immunohistochemistry, which indicate a single PLGA phenotype.

Virtual slide

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1059098656858324

Adenoid cystic carcinoma

Adenoid cystic carcinoma is a malignant tumor with a deceptively benign histologic appearance characterized by indolent, locally invasive growth with high propensity for local recurrence and distant metastasis. The tumor is composed of basaloid cells with small, angulated, and hyperchromatic nuclei and scant cytoplasm arranged into 3 prognostically significant patterns: cribriform, tubular, and solid. Some tumors undergo dedifferentiation into a high-grade form. Numerous studies have attempted to elucidate accurate histologic prognostic features but have often yielded conflicting results. Microarray analysis and gene expression profiling have provided new potential diagnostic and prognostic markers. However, tumor grade, stage, lymph node metastasis, invasion of major nerves, and margin status remain the most consistent predictors of prognosis. The combination of surgery and postoperative radiation therapy has improved locoregional control of the disease. Despite this achievement, late local recurrence and distant metastasis rates remain high and may occur decades after initial diagnosis.

Misleading initial histological diagnosis of a polymorphous low-grade adenocarcinoma in situ ex pleomorphic adenoma-a case report

INTRODUCTION

Polymorphous low-grade adenocarcinoma (PLGA) are frequent tumours of palatinal minor salivary glands. They appear clinically as solid mass located beneath intact surface epithelium, thus quite similar with benign neoplasm. PLGA displays a low tendency of aggressive behaviour. The correct aetiology of this disorder is still unknown.

CASE REPORT

In this contribution, a PLGA is reported which was located in a pleomorphic adenoma (PA). Out of an initially incisional biopsy, only the benign part of the lesion was diagnosed. Definitive histological examination of the whole tumour revealed a small malignant fraction of the specimen besides a major part of benign tissue formations (PA).

CONCLUSION

This case shows the uncertain confidence of incisional biopsy, the variably biologic behaviour of PA, providing hints for consideration of the PLGA aetiology and highlights both the necessity to remove whole PA-like lesions as well as to perform systematically histological examination of whole specimens.