Mucinous cystadenoma of the lung

Definition

A localised cystic mass filled with mucin and surrounded by a fibrous wall lined by benign mucinous columnar epithelium.

Epidemiology

This is an extremely rare tumour occurring most often in late adult life.

Clinical features

Lesions are usually asymptomatic.

Radiology

The lesion is usually peripheral.

Macroscopic appearances

There is a unilocular cyst unassociated with airways. The wall is uniformly thin.

Histopathology

The cyst is lined by a discontinuous layer of mucinous cells. There are foci of stratification and papillary infoldings1, but micropapillary fronds, necrosis and atypia2 are lacking. Extravasated mucin may cause a foreign body giant cell reaction.

Immunohistochemistry

	broad spectrum cytokeratins	positive
	CEA	rarely positive2
	surfactant protein	negative
	PCNA	<10% of nuclei
	Ki-67	<15% of nuclei

Differential diagnosis

Mucinous cystadenocarcinoma
Mucinous adenocarcinoma
Mucinous bronchoalveolar carcinoma
Congenital cystic adenomatoid tumour
Bronchogenic cyst

Management

Resection

Prognosis

Benign2. Rarely, rupture into the pleura causes pleural pseudomyxoma.

References

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

1Kragel PJ, Devaney KO, Meth BM, et al. Mucinous cystadenoma of the lung. A report of two cases with immunohistochemical and ultrastructural analysis. Arch Pathol Lab Med 1990; 114:1053-6

2Roux FJ, Lantuejoul S, Brambilla E, et al. Mucinous cystadenoma of the lung. Cancer 1995; 76:1540-4

This page last revised 1.4.2005.