A rare case of intraosseous polymorphous low-grade adenocarcinoma (PLGA) of the maxilla

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 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: a case report

We present a case of de novo polymorphous low-grade adenocarcinoma (PLGA) arising in a minor salivary gland with a relatively large radiographic extent compared with that of most of the PLGAs reported. This paper describes the radiographic extent of the lesion and the findings of CT imaging.

Low-grade papillary adenocarcinoma of the palate: the significance of distinguishing it from polymorphous low-grade adenocarcinoma

Low-grade papillary adenocarcinoma (LGPA) represents a relatively rare histological variant of polymorphous low-grade adenocarcinoma (PLGA). There has been a debate as to whether LGPA is associated with greater aggressive potential compared to PLGA; this is further obfuscated by the fact that diagnostic criteria for LGPA have not been well-defined. We believe that this is the first report of a patient with LGPA who developed metastases to the femur and scalp. We review the published evidence for classifying LGPA as distinct from PLGA. The weight of published data does support the idea that LGPA is oncologically distinct from LGPA. However, as uniform diagnostic criteria are lacking, we suggest a cut-off value of 10% or greater papillary formation as being necessary to separate LGPA from PLGA.

Polymorphous low grade adenocarcinoma presenting an uncommon radiographic aspect

The aim of this study was to present clinical, histological and immunohistochemical aspects of a polymorphous low grade adenocarcinoma occurring in the mandible. A radiolucent tumour, located in the right mandible, was removed from a 40-year-old woman. Radiographic and CT exams revealed that the lesion expanded bucco-lingual cortical plates and presented an irregular scalloping of the bone. The surrounding lining mucosa was intact. The patient underwent total surgical removal of the lesion with an intraoperative biopsy. Histological diagnosis was polymorphous low-grade adenocarcinoma confirmed by immunohistochemical study. One-year follow up was uneventful. The accurate diagnosis of lesions presenting unusual clinical aspects, as the one presented here, is critical for correctly handling treatment.