Polymorphous low-grade adenocarcinoma: a study of 40 cases with long-term follow up and an evaluation of the importance of papillary areas.

Forty cases of polymorphous low-grade adenocarcinoma with a minimum of 10 years of follow up were reviewed. The patients included 13 men and 27 women age 22 to 71 years (median age, 54 years); 30 were white and 10 were black. The tumors were all intraoral, and the palate was the most common site (n = 24). Histologically, the neoplasms were characterized by nonencapsulated, infiltrative borders: bland, regular nuclei; and highly variable growth patterns, including tubular, solid, papillary, microcystic, cribriform (with true lumens), pseudoadenoid cystic (without true lumens), fascicular, single file, and strand-like. Papillary areas of more than focal extent were present in 17 cases, but these cases were otherwise similar to the remainder and were considered to form part of the spectrum of polymorphous low-grade adenocarcinoma. Thirteen patients had local recurrence, which was not controlled by subsequent treatment in six; six patients had cervical lymph node metastasis; three patients had distant metastasis; and five patients died of or with tumor after prolonged periods. There was a statistically significant relationship between more than focal papillary growth and cervical lymph node metastasis, and between positive or unknown surgical margins and local recurrence (although not uncontrolled local recurrence); however, these were the only independent statistically significant correlations found between any clinical or pathologic parameter and any aspect of tumor behavior or patient survival.