Polymorphous Low Grade Adenocarcinoma: Case Series and Review of Surgical Management

Clinicopathological Features of 26 Intraoral Polymorphous Adenocarcinomas from a Single Brazilian Institution

PURPOSE

This study describes a large, well-documented case series of salivary gland polymorphous adenocarcinomas (PAC) from a single Brazilian center.

METHODS

Demographic data, clinical presentation, histopathological and immunohistochemical features from 26 cases of PAC were analyzed and discussed in detail.

RESULTS

Most patients were females (n = 21), with a ratio of 1:4.2 (male: female) with a mean age of 58.8 years (ranging from 36 to 84 years). The most common clinical presentation was a fibrocollagenous, firm nodular lesion, with a mean size of 2.46 cm (ranging from 0.5 to 3 cm). Most lesions occurred on the palate (n = 16), followed by buccal mucosa (n = 3), upper lip (n = 3), buccal vestibule (n = 2) and alveolar ridge (n = 1). Histologically, various growth patterns were observed, including tubular, solid, cribriform, papillary, and cystic. Additionally, glomeruloid slit-like structures, mucous, and clear cells were noted. Surface papillary epithelial hyperplasia was observed in a few cases. Nine cases exhibited myxoid and collagenous areas, while two cases showed fusiform areas and another case demonstrated squamous differentiation. Clear cell predominance was noted in two cases, and peri- and intraneural invasion was seen in eight cases. Immunohistochemical analysis revealed positivity for S-100, p63 and CK7, and negativity for p40 in all cases. The Ki-67 proliferation index was markedly low in most cases, with a mean of 2.5%.

CONCLUSION

We have provided a broad, detailed description of the clinical and microscopic features of PAC in a large, Brazilian cohort. These findings, in a resource-limited area, may be quite useful for establishing a proper diagnosis.

Mistaken identity of polymorphous low-grade adenocarcinoma treated as periapical lesion in anterior maxilla: A case report

This report presents a rare case of polymorphous low-grade adenocarcinoma (PLGA) in the anterior maxilla, mimicking a periapical lesion. A 56-year-old male reported with a painless swelling in the maxillary right canine-premolar region. The patient gave a history of root canal therapy for the same teeth one month ago. On intraoral examination, the involved teeth were restored with ceramic crowns. Radiographic examination revealed inadequate obturation with an ill-defined radiolucency in the periapical region. 3D cone beam computer tomography (CBCT) revealed erosion of the buccal cortical plate near the apices of the roots. Endodontic re-treatment was performed on both the teeth. Following this, the lesion was excised and submitted for histopathological analysis wherein it was identified as PLGA. Computerised tomographic (CT) scan and positron emission tomography scan (PET) results showed no regional or distant metastasis. Under general anaesthesia, the teeth were extracted, and wide surgical excision of the anterior maxilla was done till the healthy bone was exposed. Healing was uneventful during the follow-up period.

Polymorphous Adenocarcinoma: A Rare Case Report with Unique Radiographic Appearance on CBCT

BACKGROUND

Polymorphous low-grade adenocarcinoma (PLGA) is a slow growing malignant tumor of minor salivary glands and is generally of indolent nature. However, according to the most recent WHO Classification of Salivary Gland Tumors (2017), the cancer is classified as Polymorphous AdenoCarcinoma (PAC). PAC presents as a less aggressive tumor, though it could on rare occasions demonstrate distant metastasis. Case Presentation. A 47-year-old man who was referred by a private practitioner for a CBCT scan in reference to a proliferative soft-tissue growth in the hard palate. The growth was mild and tender and there was Grade III mobility in relation to all the maxillary teeth. Panoramic radiograph taken previously had revealed evidence of alveolar bone loss in relation to the maxillary teeth and was inconclusive of any other findings. The CBCT scan revealed evidence of moth-eaten appearance of maxilla with destruction of medial and lateral walls and floor of maxillary sinus. There was also evidence of involvement of right eustachian tube, ethmoidal wall, and nasopalatine canal. An intraosseous malignancy of the palate was suspected, and a total maxillectomy was performed. The tissue sample was sent for histopathological assessment wherein changes diagnostic for polymorphous low-grade adenocarcinoma of the palate were observed.

CONCLUSION

PAC is a distinct, yet commonly occurring, minor salivary gland tumor with varied clinical and histologic appearance. This case report highlights the importance of CBCT in diagnosing the intraosseous involvement of such tumors which can help shed some light in enhancing our knowledge about the minor salivary gland malignancies like PAC.

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.

Intraoral Pigmented Low-Grade Adenocarcinoma, Not Otherwise Specified: Case Report and Immunohistochemical Study

Salivary adenocarcinoma, not otherwise specified (AdCaNOS) is a rare malignant tumor with potential diagnostic challenge, which mainly affects the parotid glands; however, the minor salivary glands can also be involved by AdCaNOS. This paper reports a case of a 45-year-old Afro-descendant woman complaining of a slow-growing mass with 6 months of evolution in the left superior vestibular fornix. Microscopic examination revealed an infiltrative epithelial neoplasm composed of predominantly solid growth pattern, arranged in a lobular configuration, admixed with glandular or ductal structures. Perineural invasion was evident. The tumor cells were polygonal or oval showing focally mild nuclear pleomorphism, and eosinophilic or clear cytoplasm. Notably, some areas exhibited intracytoplasmic pigment granules mainly in non-luminal cells, as well as sebaceous-like cells, discrete hyaline material deposition and foci of infiltration of residual salivary gland parenchyma. Tumor cells were negative for PAS, mucicarmine and Alcian blue stains. By immunohistochemistry, the tumor cells were diffuse and strongly positive for pan-cytokeratin (CK) AE1/AE3, 34betaE12 CK, vimentin, p63 and S100. CK7 and EMA strongly highlighted the ductal structures. Solid areas also showed diffuse and moderate expression of CD56. Podoplanin (D2-40), GFAP and Calponin, followed by DOG-1, were focally positive; whereas CK20, α-SMA, h-Caldesmon, CD57, ERBB2/HER2 and p53 were negative. Ki-67 was < 2%. Consecutive serial tissue sections using CD57 confirmed the perineural invasion. Positivity for HMB-45 and MART-1/Melan-A, as well as Fontana-Masson stain (and potassium permanganate bleaching-sensitive), identified the pigment granules as melanin. To the best of our knowledge, this is the first case of intraoral low-grade AdCaNOS with intracytoplasmic melanin granules.

Synchronous Polymorphous Adenocarcinoma and Canalicular Adenoma on the Upper Lip: An Unusual Presentation and Immunohistochemical Analysis

Multiple salivary gland tumors (MSGTs) are most common in the major than minor salivary glands. The most MSGTs are synchronous, either benign or malignant. A 61-year-old woman was referred presenting nine submucosal nodules, firm to fluctuant, being five nodules on the right side and four nodules on the left side of the upper lip. An incisional biopsy was performed. Hematoxylin and eosin staining was performed in 5-µm sections for histopathologic analysis. Immunohistochemical reactions were carried out in 3-µm sections in accordance with manufacturer's instructions. The histopathological analysis showed focal area containing low-grade polymorphous adenocarcinoma (PAC) and multiple canalicular adenomas (CAs). Immunohistochemical analysis for each lesion was carefully investigated. Here, we present an unusual case of synchronous PAC and multiple CAs of the minor salivary glands, affecting the upper lip, which appears to be the first case showing PAC and CA.

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 of the upper lip: 11 cases of an uncommon diagnosis

OBJECTIVE

The aim of this case study was to describe an international case series of polymorphous low-grade adenocarcinoma (PLGA) affecting the upper lip.

MATERIAL AND METHODS

Over a 30-year-period, the files of five pathology services were reviewed for PLGA affecting the upper lip. Hematoxylin and eosin-stained slides were reviewed by three oral and maxillofacial pathologists, and microscopic features were described. Clinical data were retrieved from patients' medical records.

RESULTS

The review identified 11 cases of upper lip PLGAs, with a complete set of clinical data available for 5 cases. There was a male predominance (1.2:1), and the mean age was 58.7 years. Most cases presented as small asymptomatic swellings that resembled benign tumors. All patients underwent surgery, and no recurrences or metastases were reported in the 8 cases from which follow-up data were available. Microscopically, the typical polymorphic architectural arrangement of PLGA was seen in all cases, with lobular, trabecular, papillary, and cribriform patterns identified. Perineural invasion, normal gland entrapment, Indian filing, and concentric growth were frequently identified.

CONCLUSION

PLGA must be included in the list of differential diagnoses of tumors affecting the upper lip because of its similar clinical presentation to benign entities. The follow-up data available from 8 of 11 cases suggest that these tumors follow a low-grade clinical course, similar to the majority of palatal cases of PLGA.

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.