Epithelial-myoepithelial carcinoma of bronchus

This rare tumour most commonly occurs in the salivary glands and has rarely been described in other organs with salivary-type seromucinous glands including breast, sweat glands and bronchus. Nineteen cases had been reported in bronchi by 2001. The tumour consists of myoepithelial cells with spindle cell, clear cell or plasmacytoid morphology and varying amounts of duct-forming epithelium.

Synonyms

Adenomyoepithelioma, myoepithelioma, epithelial-myoepithelial tumour, malignant mixed tumour comprising epithelial and myoepithelial cells.

Clinical features

This is a tumour of adults, often 50 to 60 years old. Clinical symptoms and imaging are those expected from an endobronchial tumour.

Macroscopic appearances

The tumours are predominantly endobronchial. Tumours are solid to gelatinous.

Histopathology

The myoepithelial cells show spindle, clear cell or plasmacytoid4 differentiation. There is a variable proportion of duct-forming epithelium. Ducts are lined by two layers of cells, inner cuboidal cells with eosinophilic cytoplasm and outer clear cells.

Immunohistochemistry

cytokeratin (AE1/AE3. The five cases published by Fulford et al were positive with MNF116.)	16/18 (positivity predominantly in luminal cells, some cases also in clear and spindle cells)1
EMA	12/12 (positivity mainly in luminal cells, in spindle cells in one case)1
S-100	16/19 (positivity in outer layer of epithelial cells and in spindle cells)1
SMA	18/19 (positivity in outer layer of epithelial cells and in spindle cells)1
CD68	0/51
CD34	1/5 (positivity in spindle cells)1
vimentin	4/5 (positivity in spindle cells)1
CD56	0/51
Factor VIII	0/51

Ultrastructure

The tumor is characterised by a large numbers of microfilaments in the cytoplasm and layers of basement membrane-like material in the intercellular spaces.

Differential diagnosis

pleomorphic adenoma: includes a (myxo)chondroid component.
adenoid cystic carcinoma: more infiltrative with cribriform areas.
adenosquamous carcinoma with an amyloid-like stroma

If clear cells predominate::

benign clear cell tumour of lung
metastatic renal cell carcinoma
large cell carcinoma of the lung of clear cell type
clear cell carcinoid
bronchoalveolar adenocarcinoma with myoepithelial cells
adenosquamous carcinoma with amyloid-like stroma

Management

Resection

Prognosis

The prognosis is usually good with lack of recurrence or nodal metastases after resection. The cases which have recurred have had a significant mitotic rate (up to 13/10 HPF), necrosis, pleomorphism and have been predominantly myoepitheliomatous. Long term follow-up is not yet generally available, although late recurrences may occur. High-grade transformation has not been described.

References

Tumours of the Lung, Pleura, Thymus and Heart. WHO Classification of Tumours. IARC Press 2004.

1 Fulford, L. G., Kamata, Y., Okudera, K. Epithelial-myoepithelial carcinomas of the bronchus. Am J Surg Pathol 2001;25:1508-1514. This paper summarises immunoreactivity from:

2 Cagirici U, Sayiner A, Inci I, et al. Myoepithelioma of the lung. Eur J Cardiothorac Surg 2000; 17: 187-9.

3 Hayes MM, van der Westhuizen NG, Forgie R. Malignant mixed tumor of bronchus: a biphasic neoplasm of epithelial and myoepithelial cells. Mod Pathol 1993; 6: 85-8.

4 Higashiyama M, Kodama K, Yokouchi H, et al. Myoepithelioma of the lung: report of two cases and review of the literature. Lung Cancer 1998; 20: 47-56.

5 Horinouchi H, Ishihara T, Kawamura M, et al. Epithelial myoepithelial tumour of the tracheal gland. J Clin Pathol 1993; 46: 185-7.

6 Miura K, Harada H, Aiba S, et al. Myoepithelial carcinoma of the lung arising from bronchial submucosa. Am J Surg Pathol 2000; 24: 1300-4.

7 Nistal M, Garcia-Viera M, Martinez-Garcia C, et al. Epithelial-myoepithelial tumor of the bronchus. Am J Surg Pathol 1994; 18: 421-5.

8 Papla B, Galazka K, Malinowski E. Epithelial-myoepithelial carcinoma of the bronchus. Pol J Pathol 2000; 51: 153-7.

9 Pelosi G, Fraggetta F, Maffini F, et al. Pulmonary epithelial-myoepithelial tumor of unproven malignant potential: report of a case and review of the literature. Mod Pathol 2001; 14: 521-6.

10 Ryska A, Kerekes Z, Hovorkova E, et al. Epithelial-myoepithelial carcinoma of the bronchus. Pathol Res Pract 1998; 194: 431-5.

11 Shanks JH, Hasleton PS, Curry A, et al. Bronchial epithelial-myoepithelial carcinoma. Histopathology 1998; 33: 90-1.

12 Strickler JG, Hegstrom J, Thomas MJ, et al. Myoepithelioma of the lung. Arch Pathol Lab Med 1987; 111: 1082-5.

13 Tsuji N, Tateishi R, Ishiguro S, et al. Adenomyoepithelioma of the lung. Am J Surg Pathol 1995; 19: 956-62.

14 Wilson RW, Moran CA. Epithelial-myoepithelial carcinoma of the lung: immunohistochemical and ultrastructural observations and review of the literature. Hum Pathol 1997; 28: 631-5.

This page last revised 8.4.2005.