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Year : 2014  |  Volume : 57  |  Issue : 3  |  Page : 456-459
Clear cell myoepithelial carcinoma ex pleomorphic adenoma

Department of Pathology, Seth GS Medical College and KEM Hospital, Mumbai, Maharashtra, India

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Date of Web Publication14-Aug-2014


Pleomorphic adenoma is the most common epithelial neoplasm of lacrimal gland. A clear cell myoepithelial carcinoma arising in the background of pleomorphic adenoma is common in the salivary glands but very rare in the lacrimal glands. We report the case of a 27 year old man whose lacrimal gland pleomorphic adenoma recurred several times over a period of four years and ultimately evolved into a clear cell myoepithelial carcinoma ex pleomorphic adenoma.

Keywords: Carcinoma ex pleomorhic adenoma, clear cell myoepithelial carcinoma, lacrimal gland myoepithelial carcinoma

How to cite this article:
Rabade NR, Goel NA. Clear cell myoepithelial carcinoma ex pleomorphic adenoma. Indian J Pathol Microbiol 2014;57:456-9

How to cite this URL:
Rabade NR, Goel NA. Clear cell myoepithelial carcinoma ex pleomorphic adenoma. Indian J Pathol Microbiol [serial online] 2014 [cited 2020 May 29];57:456-9. Available from: http://www.ijpmonline.org/text.asp?2014/57/3/456/138768

   Introduction Top

Lacrimal gland tumors are seldom encountered in clinical practice. Of the space occupying lesions encountered in the gland lymphomas and inflammatory lesions predominate. The reported incidence of primary epithelial neoplasms varies from 23% to 70% in literature. [1],[2] The lacrimal and salivary glands are histologically comparable. Most epithelial neoplasms of the salivary glands also affect the lacrimal gland. Pleomorphic adenoma is the most common benign epithelial tumor of lacrimal glands with an incidence of up to 65% of all epithelial neoplasms. [1],[2] Pleomorphic adenoma may undergo malignant transformation in less than 10% of the cases. [1] Carcinoma ex pleomorphic adenoma (PA) may occur in the form of undifferentiated carcinoma, poorly differentiated carcinoma, adenoid cystic carcinoma, or myoepithelial carcinoma. [3] Myoepithelial carcinoma is a malignant tumor of myoepithelial cells that may arise de novo or within a preexisting PA or benign myoepithlioma. Myoepithelial carcinoma arising in the background of PA is extremely rare with only a handful of cases reported in the lacrimal gland.

We report a case of clear cell type myoepithelial carcinoma ex PA in the lacrimal gland, an entity hitherto unreported in English literature.

   Case report Top

A 27-year-old man came to our outpatient department in June 2011 with complaints of decreasing of vision and proptosis of the right eye and swelling over the right eyebrow of 6 weeks duration. On examination, there was a 3 cm × 2 cm hard mass over the right eyebrow. Vision in the right eye was reduced to finger counting at three feet. Extraocular movements were restricted. Left eye had 6/12 vision. Magnetic resonance imaging showed a well-defined, lobulated, contrast-enhancing mass in the superolateral compartment of right orbit with erosion of the lateral wall and roof and extending into the right frontal region.[Figure 1]a and [Figure 1]b Infiltration into the adjacent dura and compression of the frontal lobe was also present. The patients lesion had three previous surgical procedures; first in July 2007 at another hospital, then in December 2008, and again in February 2010 at our hospital. The patient presented with diminution of vision and swelling on all the three occasions. Although his vision did improve slightly after the first surgery postoperatively, he developed corneal opacity and subsequently, the eye needed to be eviscerated at the second surgery at our hospital. The initial diagnosis was recurrent PA. It was a well-encapsulated tumor showing abundant chondromyxoid stroma and both epithelial as well as myoepithelial components.[Figure 2] and [Figure 3] In its recurrence, the tumor showed an extensive myoepithelial component. The myoepithelial component was predominantly composed of clear cells. No immunohistochemical studies were carried out on the tumor at the time. The second recurrence however showed a very different picture. The tumor was composed exclusively of polygonal to plump spindloid cells with abundant clear cytoplasm and oval to angulated hyperchromatic nuclei [Figure 4]. Scattered mitotic figures were seen. Infiltration into surrounding bony trabeculae [Figure 5] and skeletal muscle was also seen. The features of PA were no longer seen. A differential diagnosis between clear cell myoepithelial carcinoma and clear cell carcinoma-not otherwise specified (NOS) was sought. However, positivity for calponin tipped the balance in favor of clear cell myoepithelial carcinoma.
Figure 1: (a and b) Magnetic resonance imaging June 2011-well-defined, lobulated, contrast enhancing mass in the superiolateral compartment of right orbit with erosion of the lateral wall and roof and extending
into the right frontal region with infiltration into the adjacent dura

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Figure 2: Pleomorphic adenoma-well-encapsulated tumor showing abundant chondromyxoid stroma, both epithelial and myoepithelial components

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Figure 3: Chondromyxoid stroma

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Figure 4: Clear cell myoepithelial carcinoma-nests and cords of cells with clear cytoplasm

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Figure 5: Clear cell myoepithelial carcinoma showing infiltration of bone

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Following the surgery the patient recovered well. The clinical course was uneventful for the next 14 months. The patient was advised radiotherapy, but received none and was lost to follow-up until he returned with the above complaints. The current tumor was excised along with evisceration of the eye. The tumor was received as multiple fragmented bits. The eye showed no involvement by the tumor. The tumor fragments showed similar histology as described above. There was diffuse strong immunopositivity for calponin. CD10 and cytokeratin (CK) showed focal positivity [Figure 6], whereas epithelial membrane antigen, vimentin, and S-100 were negative [Figure 7]. The postoperative recovery was good with no additional neurological deficit.
Figure 6: Clear cell myoepithelial carcinoma-diffuse calponin positivity

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Figure 7: Clear cell myoepithelial carcinoma-epithelial membrane antigen negative

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   Discussion Top

As mentioned previously, salivary and lacrimal glands are homologous and so are the tumors occurring in them. Incomplete excision of a PA may lead to recurrence or malignant transformation. The morphology of the tumor following malignant transformation is varied. Myoepithelial tumors account for only 1% of all the salivary gland tumors and 90% of these are benign. [4] Only a handful of cases (six) in the lacrimal gland have been reported in English literature. [5] Diagnostic criteria for myoepithelial carcinoma are exclusive myoepithelial differentiation (morphologic and/or immunohistochemical) and presence of mitoses >7/hpf (Ki-67 index >10%), necrosis, or infiltration into adjacent tissue. [6] Our diagnosis of myoepithelial carcinoma was based on morphologic and immunohistochemical myoepithelial differentiation and local invasion.[Figure 5]-7] The myoepithelial cells show varied histomorphology such as epithelioid, spindle, plasmacytoid, clear, and mixed. [7] When more than 75% of the cells within the tumor are of a single cell type, the tumor is classified as that cell type, whereas, when 2 or more cell types predominate, the tumor is designated as mixed cell type. [6] More than 75% cell population was clear in our case and hence, it is termed as clear cell type.[Figure 4] Within the salivary glands, high incidence of recurrence for spindle and clear cell types has been documented in case reports. [8]

On immunohistochemical analysis tumors are usually positive for vimentin, S-100, calponin, CD10, p63, and pan-CK. [8] Our case showed positivity for calponin, CD10, and CK.

The preexisting benign mixed tumor may not always be demonstrable as the malignant tumor may overgrow and completely obliterate the evidence of its existence. A history of the rapid increase in size may be the only clue to the development of malignancy. Our patient followed up for 4 years, and "clear" progression of the tumor from a benign mixed tumor to a PA with extensive myoepithelial component and then finally to frank myoepithelial carcinoma is seen. In salivary glands the time interval for malignant transformation, as described in case reports, varies from 6 to 43 years. [9]

Case reports of malignant transformation of PA into myoepithelial carcinoma have been published in literature and are rarer than primary myoepithelial carcinomas of the lacrimal gland. [7],[10] Wiwatwongwana et al. describe the case of a 84-year-old man with myoepithelial carcinoma arising in the background of PA of epithelioid type with focal clear cell areas as against our case, which was purely clear cell type. [7] High-grade transformation of an adenoid cystic carcinoma into myoepithelial carcinoma has also been reported. [11]

As very few cases of myoepithelial carcinoma have been reported from the lacrimal gland, its biological behavior is difficult to determine. However, considering the homology between the salivary and lacrimal glands and their tumors a similar behavior could be expected.

Nagao et al., in a study of salivary gland myoepithelial carcinomas, stated that when arising in the background of PA, myoepithelial carcinomas tend to follow a long course with multiple recurrences, as is also evident in our case. [12]

   References Top

Weis E, Rootman J, Joly TJ, Berean KW, Al-Katan HM, Pasternak S, et al. Epithelial lacrimal gland tumors: Pathologic classification and current understanding. Arch Ophthalmol 2009;127:1016-28.  Back to cited text no. 1
Wang XN, Qian J, Yuan YF, Zhang R, Zhang YQ. Space-occupying lesions of the lacrimal gland at one tertiary eye center in China: A retrospective clinical study of 95 patients. Int J Ophthalmol 2012;5:208-11.  Back to cited text no. 2
Santos RR, Damasceno RW, de Pontes FS, Cursino SR, Nishiwaki-Dantas MC, Vital Filho J, et al. Ten-year follow-up of a case series of primary epithelial neoplasms of the lacrimal gland: Clinical features, surgical treatment and histopathological findings. Arq Bras Oftalmol 2010;73:33-9.  Back to cited text no. 3
Barnes L, Eveson JW, Reichart P, Sidransky D. World Health Organization Classification of Tumours: Pathology and Genetics, Head and Neck Tumours. Lyon,France: IARC Press; 2005.  Back to cited text no. 4
Moret A, Tabareau-Delalande F, Joly A, de Muret A, Goga D, Laure B. Myoepithelial carcinoma of the lacrimal gland. Rev Stomatol Chir Maxillofac Chir Orale 2014;115:172-7.  Back to cited text no. 5
Savera AT, Sloman A, Huvos AG, Klimstra DS. Myoepithelial carcinoma of the salivary glands: A clinicopathologic study of 25 patients. Am J Surg Pathol 2000;24:761-74.  Back to cited text no. 6
Wiwatwongwana D, Berean KW, Dolman PJ, Rootman J, White VA. Unusual carcinomas of the lacrimal gland: Epithelial-myoepithelial carcinoma and myoepithelial carcinoma. Arch Ophthalmol 2009;127:1054-6.  Back to cited text no. 7
Kane SV, Bagwan IN. Myoepithelial carcinoma of the salivary glands: A clinicopathologic study of 51 cases in a tertiary cancer center. Arch Otolaryngol Head Neck Surg 2010;136:702-12.  Back to cited text no. 8
McCluggage WG, Primrose WJ, Toner PG. Myoepithelial carcinoma (malignant myoepithelioma) of the parotid gland arising in a pleomorphic adenoma. J Clin Pathol 1998;51:552-6.  Back to cited text no. 9
Bertschinger D, Oberic A, Moulin A, Hamédani M. Malignant transformation of a "benign" lacrimal gland tumor. Klin Monbl Augenheilkd 2010;227:321-3.  Back to cited text no. 10
Argyris PP, Pambuccian SE, Cayci Z, Singh C, Tosios KI, Koutlas IG. Lacrimal gland adenoid cystic carcinoma with high-grade transformation to myoepithelial carcinoma: Report of a case and review of literature. Head Neck Pathol 2013;7:85-92.  Back to cited text no. 11
Nagao T, Sugano I, Ishida Y, Tajima Y, Matsuzaki O, Konno A, et al. Salivary gland malignant myoepithelioma: A clinicopathologic and immunohistochemical study of ten cases. Cancer 1998;83:1292-9.  Back to cited text no. 12

Correspondence Address:
Nikhil R Rabade
Ashwini Nursing Home, Sai Chowk, Pimpri, Pune - 411 017, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.138768

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]

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