Polymorphous low-grade adenocarcinoma of the tonsil: report of a case and review of the literature

Polymorphous adenocarcinoma of minor salivary gland: Case presentation and literature review

INTRODUCTION AND IMPORTANCE

Polymorphous low-grade adenocarcinoma (PLGA) is a rare neoplasm arising from minor salivary glands, representing approximately 3 % of head and neck tumors. The clinical presentation of PLGA is defined as a painless, slow-growing tumor, mostly occurring in the palate. We report a case of PLGA with a rare presentation.

CASE PRESENTATION

A 76-year-old male, known case of hepatitis B, diabetes, and hypertension, presented to the emergency department complaining of spitting blood and dysphagia. Imaging showed a heterogeneous enlarged left tonsil with hyperemia of the mucosa, and air foci. Biopsy with excisional biopsy confirmed the diagnosis of PLGA. The patient underwent completion tonsillectomy and selective neck dissection which yielded tonsillar tissue with underlying PLGA, and reactive lymph nodes with no malignant tissue respectively, margins were negative for malignancy.

CLINICAL DISCUSSION

Polymorphous low-grade adenocarcinoma is a rare lesion with clinical behavior resembling that of a benign neoplasm. Predominantly occurring in the oral cavity, especially on the hard palate, buccal mucosa, and retromolar region, with fewer cases in the upper lip. Occurrence in the nasopharynx and oropharynx is rare. PLGA presents as painless slow-growing masses, typically in females aged 50-60. Local excision with careful margin evaluation is the preferred treatment, with good prognosis compared to other carcinomas.

CONCLUSION

PLGA is rare, with limited reported case from around the world. It is mostly seen in adults between their fifth and sixth decades with female predominance. PLGA is diagnosed using imaging, immunohistochemistry. Owing to the limited cases there is no standard approach to treating PLGA. However, most cases are managed with local excision and showed an excellent response in terms of tumor nonrecurrence.

Human Papillomavirus (HPV)-Related Carcinoma of the Oropharynx with Squamous Cell and Adenoid Cystic Carcinoma-Like Features: Report of a Case

We describe the heretofore unreported case of an HPV-related carcinoma of the palatine tonsil with distinct areas of squamous cell- and adenoid cystic carcinoma-like differentiation in a 54-year old patient. The morphological, immunophenotypic and molecular findings of the tumor are illustrated. We discuss the parallels between the tumor and HPV-related multiphenotypic sinonasal carcinoma (HMSC) which is well-known to exhibit adenoid cystic carcinoma-like features. A review of the literature of high-risk HPV-associated non-squamous carcinomas of the oropharynx is presented.

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.

Mucoepidermoid Carcinoma of the Palatine Tonsil

Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy in both adults and children. It has a slight female predilection and usually presents as a painless, rubber-like or soft mass, which may be fixed or mobile. Histologically, MEC is comprised of a mixture of cell types including mucous, epidermoid, and intermediate cells that can be arranged in solid nests or cystic structures. In the oral cavity, it most frequently occurs at the palate or buccal mucosa. The present paper aimed to describe an unusual case of MEC arising in the palatine tonsil.

Polymorphous low-grade adenocarcinoma: a review regarding an unusual presentation as infected odontogenic cyst

The World Health Organisation (WHO) classified polymorphous low-grade adenocarcinoma (PLGA) in 1990 as a low-grade malignancy; ICD-O 8525/3 being the assigned international code. It has been frequently described as occurring in hard- or soft-palate accessory salivary glands: some cases being described in the tongue and in major salivary glands. We present an extensive literature review about PLGA and the most common diagnostic pitfalls. We also report the first case where it was seen surrounding an impacted maxillary tooth and discuss it in regard to our review.

Polymorphous low-grade adenocarcinoma in the lung: a case report

Although uncommon, it is well recognized that salivary gland-type tumors can occur as primary lung tumors, probably arising from minor salivary-type glands lining the bronchial tree. Polymorphous low-grade adenocarcinoma (PLGA) is a rare tumor that usually originates from oral minor salivary glands. There are only 2 reported cases showing metastasis to the lung; however, a primary lung tumor has not been reported so far. In this report we describe the clinical and pathological features of another case of PLGA involving the lung, but in a patient with no evidence of a previous oropharyngeal primary. While our case probably represents another example of metastatic PLGA to the lung, to our knowledge, it is the first description of a PLGA involving the lung in the absence of a history of a previous primary oral salivary gland tumor.