Carcinoma Ex Pleomorphic Adenoma- Histopathology the Gold Standard

Case Report

Austin Clin Microbiol. 2016; 1(1): 1005.

Carcinoma Ex Pleomorphic Adenoma- Histopathology the Gold Standard

Priyanka KP, Divya U*, Majumdar S and Sridhar RV

Department of Oral Pathology & Microbiology, GITAM Dental College & Hospital, India

*Corresponding author: Divya Uppala, Department of Oral Pathology & Microbiology, GITAM University, India

Received: June 07, 2016; Accepted: June 23, 2016; Published: June 24, 2016


Pleomorphic Adenoma (PA) is an epithelial tumor of complex morphology, comprising of epithelial and myoepithelial elements arranged in a variety of patterns and surrounded by a mucopolysaccharide stroma, whereas Carcinoma ex Pleomorphic Adenoma (CXPA) is characterized by the presence of malignant transformation in pleomorphic adenoma and it is one of the rare, aggressive and poorly understood malignancies of the salivary gland. Our study is to emphasize that the histopathology is the gold standard for making the diagnosis of CXPA.

Keywords: Pleomorphic adenoma; CXPA; Mucoepidermoid carcinoma; Histopathology; Loss of heterozygosity


Carcinoma ex pleomorphic adenoma is defined as a carcinoma arising from epithelial or myoepithelial or both the components of a primary or recurrent benign PA [1]. Malignant changes in PA have been associated with long duration, tumor size, tumor recurrence, radiation therapy and advanced age [2]. In majority of the cases (75%), luminal epithelial cells undergo malignant transformation. CXPA more commonly occurs in the major salivary glands than in the minor salivary glands. Further in major salivary glands, parotid (67%) is the most frequently affected gland and sublingual is the least affected one (<1%).CXPA has the highest false-negative rate of 35.3% of all malignant salivary gland tumour, which is due to its tendency to involve the deep lobe, in contrast to the Pleomorphic adenoma which tends to involve the superficial lobe [3]. This is one of the reasons for delay in diagnosis through Fine Needle Aspiration Cytology. And being a rare carcinoma with considerable false-negativity, it often poses a great challenge to clinicians as well pathologists.

Case Presentation

A 50-year-old male presented with a painless mass in the right preauricular area since 5 years, for which he underwent FNAC and report showed Pleomorphic Adenoma. But, the patient did not take any treatment. A sudden rapid growth was noticed in the last 3 months, for which patient consulted the surgeon. On extra-oral examination, the mass was ovoid in shape, firm in consistency, mobile, non-tender and measuring about 4x3 cm in size. The skin over the swelling was normal. CT and MRI showed a single ovoid well-circumscribed mass in the right parotid space measuring about 3x2x1.5 cm (Figure 1). Then the patient was advised excisional biopsy of the lesion. Macroscopically, the mass was ovoid, firm with nodular surface and completely encapsulated. Cut surface of the mass was greyish-white in colour (Figure 2). Microscopically, the soft tissue section showed an encapsulated tumor composed of a mixture of ductal epithelial and myoepithelial cells in a hyalinized mesenchymal background with the absence of infiltration of tumor cells in the peripheral serous acini and adipose cells (Figure 3). Foci of section showed neoplastic epithelial cells which were cuboidal in shape and arranged in the form of sheets and ducts filled with eosinophilic material and neoplastic myoepithelial cells are mostly plasmacytoid type, which were arranged in sheets and interlacing cords (Figure 4). Another part of the section showed capsular infiltration of sheets of neoplastic cells. Some areas showed MEC pattern with Sheets of epidermoid cells and mucoid cells. Plasmacytoid cells showed nuclear pleomorphisim with open faced nucleus and many nucleoli. Another part of the section shows squamous metaplasia of neoplastic cells (Figure 5 & 6). Immunohistochemistry - myoepithelial cells showed positivity for S100 and SMA (Figure 7). All the above features were pointing towards a carcinoma in addition to Pleomorphic Adenoma. Thereby a diagnosis of minimally invasive CXPA with the malignant component of mucoepidermoid carcinoma was made. Lobectomy of the right parotid was done. No recurrence and Metastasis was noticed till now.