Send Orders for Reprints to
[email protected] Current Respiratory Medicine Reviews, 2016, 12, 000-000
1
About a Long Lasting Primary Pleomorphic Adenoma of the Lung with a Misleading Pattern Mona Mlika*,1,3, Walid Gattoufi1, Emna Braham1, Hazem Zribi2,3, Tarek Kilani2,3 and Faouzi El Mezni1,3 1
Department of Pathology. Abderrahman Mami Hospital, Ariana, Tunisia
2
Department of Thoracic Surgery. Abderrahman Mami Hospital, Ariana, Tunisia
3
Université de Médecine. Tunis El Manar, Tunisia Abstract: Background: Pleomorphic adenoma is a benign mixed tumor of salivary gland type. It has been rarely reported in the lung. Our aim is to report a rare case of primary pleomorphic adenoma of the lung with a misleading pattern and to perform a mini-review of the literature. Material and methods: We report a case of pleomorphic adenoma in a 12-year-old child with a minireview of the literature in the site pubmed using the keywords: pleomorphic adenoma AND lung.
Mona Mlika
Results: Our patient presented chest pain and fever. His past medical history was characterized by recurrent pneumonia. This case is interesting because it highlights a potential consequence of PA of the lung, which is bronchial dilatation. Besides, it puts emphasis on the diversity of the architectural patterns like acinar feature which was reported in our observation and which can be confusing.
Keywords: Pleomorphic adenoma, lung, pathology, surgery. BACKGROUND Pleomorphic adenoma (PA) is a benign mixed tumor of salivary gland type and has been rarely reported in the lung with less than 100 cases in the English literature. Clinical symptoms and radiological features are non specific and the diagnosis is based, in almost all cases, on the microscopic examination [1]. We report an interesting observation about a long lasting PA of the lung with non specific clinical and radiological features and a misleading acinar pattern and globlet cells. CASE PRESENTATION We report the case of a 12-year-old child whose past medical history was particular for recurrent pneumonias and a bronchial dilatation who presented with a one-monthlasting chest pain and fever. Chest-x-ray showed a shadow of the lower right lung. Bronchial endoscopy showed an obstruction of the right bronchus. The medium and inferior bronchus was quite normal. CT-scan showed an endobronchial polypoid mass evoking a carcinoid tumor or a foreign body granuloma and lesions of bronchial dilatation (Fig. 1). A first bronchial biopsy showed an inflammatory bronchial mucosa covered by a hyperplastic squamous epithelium. We couldn’t perform a rigid bronchoscopy because of its cost. In our institution we are not able yet to perform this technique in order to obtain bigger specimen. *Address correspondence to this author at the Department of Pathology. Abderrahman Mami Hospital, Postal Code: 2037, Ariana, Tunisia; Tel: (00216) 98 53 88 62; Fax: 0021671710780; E-mail:
[email protected] 1573-398X/16 $58.00+.00
The patient underwent a right lowerlobectomy. Gross examination showed a 11x9x4 cm lobe with a 2-centimeter white endobronchial mass distant of 1 cm from the bronchial section with lesions of bronchial dilatation. Microscopic examination showed a well limited tumor with acinar structures lined by globlet cells and cordonal structures with plasmacytoid cells (Fig. 2a-c). Some acinar structures were filled with crystalloids (Fig. 2d). Tumor cells were quite regular and no mitotic figures were observed. Tumoral stroma was peculiar mainly hyaline. Immunohistochemical study was performed using cytokeratin (Dako, 1/150), EMA (Leica, 1/100), Smooth Muscle Actin (SMA) (Novocastra, 1/50), P63 (Novocastra, 1/50) and Ki-67 (Novocastra, 1/100) antibodies. Globlet cells lining the acinar structures expressed the cytokeratin and EMA antigens (Fig. 3a), while plasmacytoid cells expressed the SMA and P63 antibodies (Fig. 3b). No cell expressed the Ki-67 antibody. Facing the microscopic findings, the diagnosis of mucoepidermoid carcinoma was evoked and rapidly ruled out because of the absence of an infiltrating pattern, the absence of necrosis and the presence of myoepithelial cells expressing the P63 and the SMA antigens. The patients didn’t present complications after one year of follow up. DISCUSSION Our case is interesting because it is about a long lasting PA which induced recurrent pneumonias and bronchial dilatation. PA is a benign tumor of salivary gland type containing epithelial, myoepithelial and stromal components. In this location, benign salivary gland type tumors have been rarely reported like PA or myoepithelioma [2]. The most
© 2016 Bentham Science Publishers
2
Current Respiratory Medicine Reviews, 2016, Vol. 12, No. 2
Mlika et al.
Fig. (1). a/ Sagittal section of CT-scan showing a 1.7 mm endobronchial lesion, b/ transversal section of CT-section showing the polypoid mass, c/ CT scan showing the bronchial dilatation situated beyond the polypoid lesion.
Fig. (2). a/ Microscopic findings showing the coexistence of acinar structures and nests of plasmacytoid cells (HEx250), b/ microscopic findings showing the acinar structures lined with globlet cells (Hex400), c/ microscopic findings showing rare foci of squamous differentiation (Hex400), d/ microscopic findings showing some cristalloids within the acinar structures (HEx400).
Pleomorphic Adenoma of the Lung
Current Respiratory Medicine Reviews, 2016, Vol. 12, No. 2
3
Fig. (3). a/ Microscopic features showing the expression of the cytokeratin antibody by the epithelial cells lining the acinar structures (HEx400), b/ microscopic features showing the focal nuclear expression of P63 by the myoepithelial cells (HEx400).
frequent salivary gland type tumors reported were mainly malignant consisting in mucoepidermoid carcinoma, acinic cell carcinoma, epithelial myoepithelial carcinoma and adenoid cystic carcinoma [3-8]. PA typically arises from the tracheal and bronchial seromucous glands [9]. There is no clear gender or age predominance [10]. Patients presenting with obstructive symptoms usually have endobronchial lesions [2]. In our case, the presence of a long-lasting PA obstructing the bronchus explains recurrent pneumonia and the lesions of bronchial dilatation. Another long lasting PA has also been reported in the literature and was revealed by a pneumonia [11]. Microscopic diagnosis is the only mean of diagnosis. It can be performed on surgical specimen or biopsy but surgical resection seems to be safer because it has been reportedthatpercutaneousneedlebiopsymaybe the origin of local recurrence and consequently should be avoided [12]. The essential diagnostic features consist in the association of both epithelial and mesenchymal like tissues in variable proportions [13]. Extracellular stroma is one of the defining components of PA, ranging from scanty to abundant. According to the relative proportion of stroma and cellular components, Seifert sub-classified PA into 4 subtypes: type 1 (stroma comprises 30-50% of the tumor), type II (stroma comprises 80% of the tumor), type III (stroma comprises 2050% of the tumor) and type IV (stroma comprises similar proportion to that of type III, but there is focal monomorphic differentiation in the epithelial component) [14]. Our case belongs to type III but no therapeutic significance has been reported according to the morphologic spectrum [1]. Distinctive epithelial cell types include spindle, clear, squamous, basaloid, cuboidal, plasmacytoid, oncocytoid, mucous and sebaceous types. The various cell types are often closely associated with one another and transition from one type to another is common. Squamous differentiation is frequently abrupt and occurs as discrete islands that are seemingly superimposed on sheets of less distinctive epithelial cells. The nuclear features of all cell types are uniformly bland. Nucleoli are small or absent and mitoses are few. Crystalloids like those observed in our case are composed of collageneous substance and are more often observed in PA than in other salivary gland neoplasms with an incidence varying from 15 to 21% [13]. Concerning the stromal component, PA is characterized by the variety of the stromal component which can be myxoid, hyaline, chondroid or osseous. This variety is attributed to the myoepithelial cells which are able to produce variable amount and nature
of stroma. The most frequent reported patterns are the tubular and the insular ones [1]. In our case, the acinar phenotype with the presence of globlet cells and the peculiar tumor stroma was misleading evoking an adenosquamous carcinoma. In fact, PA is polymorphous with many possible features. To our knowledge no such a phenotype has been reported in the lung. The diversity of the morphological aspects has been attributed to the myopethial cells which seem to play a key role in the achievement of diverse morphological features [1]. Diagnostic dilemma may be caused by small, fragmented tissue samples. In these cases, a variety of neoplasms must be considered including canalicular adenoma, which contains duct-like structures and myxoid areas or mucoepidermoid carcinoma like in our observation. Immunohistochemical studies have not been particularly helpful in separating PA from other types of benign and malignant salivary gland tumors. In fact, coexpression of cytokeratin and SMA supports myoepithelial differentiation and could be observed in other types of tumors. In our case, the diagnosis of mucoepidermoid carcinoma was difficult to rule out because of the coexistence of squamous differentiation and of globlet cells. In fact, mucoepidemoid carcinoma is defined by the coexistence of mucous, epidermoid and intermediate cells but the myoepithelial cells are absent. In that case, the presence of myopethial cells expressing P63 and SMA allowed ruling out the diagnosis. Electrosurgical snare has been widely used and accepted for the management of benign airway stenosis including a tracheobronchial PA [10]. In our case, the surgical resection was performed because of the lesions of bronchial dilatation. CONCLUSION PA of the lung is a very rare tumor which may cause diagnostic concern because of its phenotypical and architectural diversity. This case illustrates the difficulty of making the diagnosis even based on microscopic features and highlights the consequences of a long lasting PA which can induce lesions of bronchial dilatation. AUTHORS’ CONTRIBUTIONS MM conceived the manuscript, WG, HZ and EB retrieved the different data, TK and FM reviewed the article.
4
Current Respiratory Medicine Reviews, 2016, Vol. 12, No. 2
Mlika et al.
CONFLICT OF INTEREST STATEMENT
[6]
The authors declare that they have no competing interests and disclose any personal or financial support.
[7]
ACKNOWLEDGEMENTS
[8]
Declared none.
[9]
REFERENCES [1]
[2] [3] [4] [5]
[10]
Margaritescu C, Raica M, Simionescu C, et al. Tumoral stroma of salivary pleomorphic adenoma- histopathological, histochemical and immunohistochemical study. Rom J Morph Emb 2005; 46: 211-23. Kourda J, Ismail O, Smati BH, Ayadi A, Kilani T, El Mezni F. Benign myoepithelioma of the lung - a case report and review of the literature. Cases J 2010; 3(1): 25. Moran CA, Suster S, Askin FB, et al. Benign and malignant salivary gland-type mixed tumor of the lung: clinicopathologic and immunohistochemical study of 8 cases. Cancer 1994; 73: 2481-90. Fechner R, Bentink BR, Askew JB. Aciniccell tumor of the lung: a histologic and ultrastructural study. Cancer 1972; 29: 501-8. Moran CA, Suster S, Koss MN. Acinic cell carcinoma of the lung (“Fechner tumor”): a clinicopathologic, immunohistochemical, and ultrastructural study of five cases. Am J SurgPathol 1992; 16: 1039-50.
Received: September 29, 2015
[11]
[12]
[13] [14]
Moran CA, Suster S, Koss MN. Primary adenoid cystic carcinoma of the lung: a clinicopathologic and immunohistochemical study of 16 cases. Cancer 1994; 73: 1390-7. Nguyen CV, Suster S, Moran CA. Pulmonary epithelialmyoepithelial carcinoma: clinicopathologic and immunohistochemical study of 5 cases. Hum Pathol 2009; 40: 36673. Yousem SA, Hochholzer L. Mucoepidermoid tumors of the lung. Cancer 1987; 60: 1346-52. Spencer H. Bronchial mucous gland tumours. Virchows Arch A PatholAnatHistol 1979; 383: 101-15. Goto T, Maeshima A, Akanabe K, et al. Bronchial pleomorphic adenoma coexisting with lung cancer. Ann ThoracCardiovascSurg 2011; 17: 174-7. Gakidis I, Mihos PT, Chatziantoniou C, Stamatelopoulos A, Eftychiadis C, Mantas C. A large neglected pleomorphic adenoma of the lung: Report of a rare case. Asian CardiovascThorac Ann 2013; 22: 620-22. Tokunaga T, Kunou H, Ishida D, et al. Pleural recurrence after surgery for pelomorphic adenoma arising from peripheral lung: computed tomography-guided percutaneous needle biopsy as a possible mechanism of local failure. Gen Thorac Cardiovasc Surg 2015; 63(8): 478-82. Ellis GL, Auclair PL. Benign epithelial neoplasms. In: Tumors of the salivary glands. AFIP Atlas of tumor pathology Series 4. ARP Press 2008: 49-71. Seifert G, Miehlke A, Haubrich J, Chilla R. Diseases of the salivary glands: diagnosis, pathology, treatment, facial nerve surgery, Georg ThiemeVerlag, Stuttgart, 1986; 65-130.
Revised: February 21, 2016
Accepted: February 22, 2016
