Alveolar adenoma

Definition

A solitary peripheral lung tumour consisting of a network of spaces lined by simple low cuboidal epithelium and associated with a scant spindle cell stroma which is sometimes myxoid.

Epidemiology

This is a very rare tumour of adults, slightly more common in women^0,6.

Clinical features

This is usually an incidental finding in an asymptomatic patient².

Radiology

The lesion is solitary and well-circumscribed^1,3. It lacks calcification. Magnetic resonance imaging demonstrated the presence of a cystic space with central fluid and thin-rim enhancement³.

Macroscopic appearances

The lesion is lobulated and multicystic.

Histopathology

The cystic spaces are filled with eosinophilic granular material and lined by flattened cuboidal or hobnail Type II pneumocytes². The cells may have clear cytoplasm⁷. There may be squamous metaplasia. The stromal spindle cells are bland. A case has been reported with areas resembling sclerosing haemangioma⁷.

Immunohistochemistry

		Epithelial cells	Stromal cells
	Cytokeratins	positive4
	Cam5.2	1/14
	AE1/AE3	1/14
	MNF116	1/17	0/17
	EMA	1/14, 1/17	0/17
	CEA	positive4
	surfactant	positive0,2, 1/15, 1/17	0/15, 0/17
	TTF-1	positive0,2, 1/17	negative4, 0/17
	SMA	0/17	focally positive4, 1/14, 0/17
	MSA		focally positive4
	Desmin	0/17	negative4,1/14, 0/17
	S-100	0/17	0/17
	CD34	0/17	0/17
	CD56	0/17	1/17
	Clara cell marker CC10	0/62
	vimentin	0/17	1/17

Ultrastructure

The lining cells contain lamellar bodies and bear blunt microvilli and zona adherens type cell junctions. They appear to be chiefly type II neumocytes⁴.

Differential diagnosis

• Lymphangioma: lining cells are negative for cytokeratins

• Sclerosing haemangioma: clear/foamy cells are not a dominent feature⁷. Stromal cells (as well as the epithelial cells) are positive for TTF-1⁷.

•  

• Adenocarcinoma,

  • bronchoalveolar carcinoma: shows lepidic growth

If clear cells are present:

• clear cell tumour of lung
  

• metatstatic renal cell carcinoma

Management

Excision

Prognosis

Benign

References

⁰Tumours of the Lung, Pleura, Thymus and Heart. WHO Classification of Tumours. IARC Press 2004.

¹Bohm J, Fellbaum C, Bautz W, et al. Pulmonary nodule caused by an alveolar adenoma of the lung. Virchows Arch 1997; 430:181-4

²Burke LM, Rush WI, Khoor A, et al. Alveolar adenoma: a histochemical, immunohistochemical, and ultrastructural analysis of 17 cases. Hum Pathol 1999; 30:158-67

³Fujimoto K, Muller NL, Sadohara J, et al. Alveolar adenoma of the lung: computed tomography and magnetic resonance imaging findings. J Thorac Imaging 2002; 17:163-6

⁴Haskovcova I, Povysil C,Pafko P [Alveolar adenoma of the lung (case report)]. Cesk Patol 1997; 33:49-52

⁵Koppl H, Freudenberg N, Berwanger I, et al. [Alveolar adenoma of the lung. Immunohistochemical characterization of type II pneumocytes]. Pathologe 1996; 17:150-3

⁶Menet E, Etchandy-Laclau K, Corbi P, et al. [Alveolar adenoma: a rare peripheral pulmonary tumor]. Ann Pathol 1999; 19:325-8

⁷Nicholson AG, Magkou C, Snead D, et al. Unusual sclerosing haemangiomas and sclerosing haemangioma-like lesions, and the value of TTF-1 in making the diagnosis. Histopathology 2002; 41:404-13

⁸Oliveira P, Moura Nunes JF, Clode AL, et al. Alveolar adenoma of the lung: further characterization of this uncommon tumour. Virchows Arch 1996; 429:101-8

⁹Shiota Y, Matsumoto H, Sasaki N, et al. Solitary bronchioloalveolar adenoma of the lung. Respiration 1998; 65:483-5

¹⁰Yousem SA,Hochholzer L Alveolar adenoma. Hum Pathol 1986; 17:1066-71

This page last revised 31.3.2005.

©SMUHT/PW Bishop