Carcinoma ex-pleomorphic adenoma of the salivary glands has a high risk of progression when the tumor invades more than 2.5 mm beyond the capsule of the residual pleomorphic adenoma

Abstract

Carcinoma ex-pleomorphic adenoma (CPA) is subclassified based on the extent of penetration of the malignant component beyond the fibrous capsule of the pre-existing pleomorphic adenoma (PA). These subclasses are considered to be prognostically significant since the non-invasive/minimally invasive groups have an excellent outcome. Nevertheless, there is no consensus as to the cutoff value to distinguish between minimal and wide invasion, even though the 2005 WHO classification defines 1.5 mm as cutoff. The objective of this study is to evaluate a consecutive series of CPA, in order to establish what the effect is of the extent of extra-capsular invasion on prognosis. Fifty-eight cases of CPA were reviewed to obtain demographic and pathological information. Extent of invasion was measured. Eleven cases were non-invasive, 9 had ≤1.5 mm invasion, and for the remainder, the depth of invasion ranged between 2.5 and >10 mm. Distant metastases or death did not occur in the first two groups. In the group with ≥2.5 mm invasion, 15 patients had progressive disease and 9 of them died. The minimum extent of invasion associated with tumor progression and death was 2.5 mm. Two histologically non-invasive carcinomas had regional lymph node metastasis. CPA with ≤1.5 mm depth of invasion has good prognosis. Nevertheless, the lymph node metastases found in two cases of this group question the concept that intracapsular/minimally invasive CPA has a prognosis similar to that of PA. The minimum extent of invasion associated with death was 2.5 mm, which is at variance with findings in other recent series. Thirteen cases with depth of invasion exceeding 2.5 mm did well, confirming that additional factors should be considered in the clinical management of these patients.

Salivary Gland Neoplasms: Does Morphological Diversity Reflect Tumor Heterogeneity

“…For instance, carcinoma ex PA (CPA) is considered a highgrade tumor and, although the carcinomatous component is often of a high-grade subtype (salivary duct carcinoma [SDC] or adenocarcinoma NOS), low-grade morphologies can also be present. Furthermore, most series have shown that it is the extent of invasion of the carcinomatous component into the surrounding tissue that has the strongest prognostic impact; intracapsular/minimally invasive tumors, irrespectively of the grade of the malignant component, have a favorable outcome [11][12][13][14]. The only neoplasms that are consistently graded in current practice are adenoid cystic carcinomas (AdCC), based on the growth pattern, mucoepidermoid carcinoma (MEC), with a combination of growth pattern and cytomorphological findings, and adenocarcinomas NOS, based on the degree of cellular atypia [1,8].…”

“…The malignant component varies in phenotype and aggressiveness, i.e., from SDC to adenocarcinoma NOS, myoepithelial carcinoma, EMC, or AdCC, among others, or even with combined morphologies [11,13,14,56].…”

Recurrent rearrangements of the PLAG1 and HMGA2 genes in lacrimal gland pleomorphic adenoma and carcinoma ex pleomorphic adenoma

“…The prognosis of salivary gland carcinomas in general depends on the disease stage, while the clinical outcome of ca-ex-PA also depends on the degree of invasion beyond the maternal PA (Seethala 2009;Antony et al 2012;Rito & Fonseca 2016;Williams et al 2017). While the extent of invasion associated with adverse outcome has been debated, intracapsular (i.e.…”

Perfusion MR imaging detection of carcinoma arising from preexisting salivary gland pleomorphic adenoma by computer-assisted analysis of time-signal intensity maps

“…In addition, the false-negative CXPA cases had no consistent TIC or histological characteristics in the present study. The poor prognostic factors for CXPA reportedly included extracapsular extension of cancer components >2.5 mm from the capsule of the preexisting PA [6]. However, the detection of extracapsular extension using MR imaging can be very challenging; in fact, the morphology of the tumor margin and capsule was indistinguishable between CXPA and PA.…”