Low-Grade Papillary Adenocarcinoma of the Palate: The Significance of Distinguishing it from Polymorphous Low-Grade Adenocarcinoma

Abstract

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.

Diagnostic Dilemma of Polymorphous Low Grade Adenocarcinoma of Hard Palate

“…Adjuvant radiotherapy is only recommended in cases with inadequate margins, perineural or perivascular spread and/or lymph node involvement [5]. The overall prognosis for PLGA is favorable with a disease specific survival rate of 97.6% on an average follow up of 9.6 years [8].…”

“…It is most commonly seen in the palate (49-77.8%), followed by either buccal mucosa or the upper lip (7.4-13.4%) and can also involve the floor of mouth, lower lip, alveolar ridge and tongue [4,5]. Clinically it presents as a firm, well circumscribed, painless, slow growing mass mostly covered by nonulcerated mucosa resembling a benign neoplasm which can be responsible for the delay in diagnosis for years.…”

Nano-hydroxyapatite and its contemporary applications

“…[2] Tumor cells are uniform and isometric; they have vesicular nuclei with pale eosinophilic cytoplasm, which seems to be washed out in appearance. [9,12] The diagnosis of PLGA may pose difficulty due to histopathological overlap with other salivary gland neoplasms. Multiple histomorphologic patterns and cytologic uniformity are features similar to those seen in AdCC and PA. Differentiating between PLGA, AdCC and PA is a diagnostic challenge especially in small biopsy sample.…”

Envisioning the Next WHO Head and Neck Classification

“…LGPA may merit nosological distinction from PLGA based on higher rates of local recurrence and regional metastases [19][20][21][22][23]. There is tremendous morphologic overlap between PLGA and LGPA (Fig.…”