Desmoplasia in Different Degrees of Invasion of Carcinoma Ex-Pleomorphic Adenoma

Abstract

Stroma desmoplasia was studied by immunohistochemistry for alpha-smooth muscle actin (alpha-SMA) in 17 instances of carcinoma ex-pleomorphic adenoma (CXPA) classified according to the presence of epithelial and myoepithelial cells and the degree of invasion: intracapsular, minimally and frankly invasive carcinoma. In "resident" pleomorphic adenoma, no desmoplasia was detected. In invasive areas of the intracapsular type of CXPA with only an epithelial component, desmoplasia started to be revealed by the presence of myofibroblasts close to the capsule. In the minimally invasive type, myofibroblasts were seen in the septum between islands of malignant cells and in focal peripheral areas of the tumor interpreted as the actual front of invasion. In the frankly invasive type of CXPA showing large blocks of cells, intense desmoplasia was seen, also separating the tumor cells from the neighboring normal tissue. In tumors with cords and/or small nests of cells, desmoplasia was very slight. In the invasive type of CXPA with a myoepithelial component, alpha-SMA expression was seen in the septum between the islands of cells. The expression was less intense and not present in all areas of the stroma. In CXPA with epithelial and myoepithelial cells, myofibroblasts were rarely seen in the septum separating sheets of cells. Thus, we may deduce that the presence of desmoplasia parallels the capacity of invasion of CXPA by epithelial cells, being minimum in the intracapsular and minimally invasive type of CXPA and increasing as the tumor becomes frankly invasive. Furthermore, we may also conclude that in CXPA with a myoepithelial component, desmoplasia is very rare.

Dynamic role of myofibroblasts in oral lesions

“…They promote tumour progression through "neo-angiogenesis" by releasing growth factors, such as fibroblast growth factor-2 [3] . A study demonstrated that the most migratory and invasive behaviour of tumour cells correlated with the presence of MFs at the invasive tumour front in OSCC because this precedes the invasive stage of the cancer [39,40] . In addition, abundant MFs in the tumour stroma correlates with a higher tumour incidence, specifically in patients aged below 60 years [19] .…”

“…In wound healing, MFs transiently acquire the phenotype [1] , which persists during fibrosis in the tumour environment because of an imbalance between the apoptosis and the proliferation of transformed cells leading to disease progression [40] .…”

“…Studies conducted on MFs in the tumour stroma of several salivary gland tumours, such as carcinoma ex pleomorphic adenoma, mucoepidermoid carcinoma (MEC), and adenocarcinoma, revealed the presence of tumour MFs at the tumour front in all the malignant lesions, which further correlated with the invasiveness of the cancer cells [40] . Gupta et al [51] demonstrated that a high MF density in adenoid cystic carcinoma and MEC at tumour front, contributing to the aggressiveness of the lesions, whereas a moderate MF density was observed in polymorphous low grade adenocarcinoma.…”

Strain Assessment in Surgically Resected Inflammatory and Neoplastic Bowel Lesions

“…RTE has shown promising results for differentiating between malignant and benign lesions in breast lumps [11], prostate tumors [12,13], thyroid nodules [14 -16], lymph nodes [17,18] and the pancreas [8,19]. Both malignant tumors and chronic inflammation may lead to the formation of soft tissue fibrosis [20,21]. Fibrosis formation in malignant tumors is called desmoplasia and may contribute to increased tissue hardness through several mechanisms involving tumor cells, stromal cells and the extracellular matrix [22].…”

Characterization of solid focal pancreatic lesions using endoscopic ultrasonography with real-time elastography

“…Strain imaging depends on several factors contributing to increased tissue hardness: increased fibrosis and desmoplastic reaction. The latter is typical of malignant tumors of the breast, bowel, and pancreas [25,26]. Increased interstitial fluid pressure (IFP) may also increase tissue incompressibility.…”