Pulmonary papillary adenoma, bronchiolar adenoma, peripheral papillary adenoma of type II pneumocytes

Some authorities consider this tumour a variant of sclerosing haemangioma.


This is a rare tumour: less than 20 cases have been reported in the literature. A case of multiple papillomas has been reported in a boy with von Recklinghausen's disease7.


The patients are usually asymptomatic with an incidental well defined peripheral pulmonary nodule or "coin lesion"5,6.

Macroscopic appearances

The tumour is well defined. Statements as to whether they involve airways vary0,5,9.


These tumours are usually well-demarcated and non-infiltrating. Cases with infiltrative margins have been reported, but the significance for their behaviour is uncertain2. The architecture is papillary, mixed with more solid areas. The cells resemble pneumocytes/Clara cells, with cuboidal to columnar cells showing eosinophilic cytoplasm. There is an absence of nuclear atypia and necrosis6. Occasional nuclear eosinophilic inclusions may be seen. Oncocytic cases are reported4.



surface cells

stromal cells


positive8, 2/22






1/11, 1/17



positive8, 1/18



positive8, 1/11, 2/22


surfactant protein

positive8, 2/22, 1/14, 0/36, 1/17, 1/18, 1/110


Neuroendocrine markers



Clara cell specific protein




Cells have microvilli2,3, sparse cell junctions3, cytoplasmic dense granules3,8 and whorled lamellar membrane inclusions2,3,4,8,9,10, features of type II pneumocytes/Clara cells.

Differential diagnosis


These tumours have never been reported to metastasis9.


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

1 Sheppard, M. N., Burke L. et al. (2003). "TTF-1 is useful in the diagnosis of pulmonary papillary adenoma." Histopathology 43(4): 404-5.

2 Dessy E, Braidotti P, Del Curto B, et al. Peripheral papillary tumor of type-II pneumocytes: a rare neoplasm of undetermined malignant potential. Virchows Arch 2000; 436:289-95

3 Fantone JC, Geisinger KR,Appelman HD Papillary adenoma of the lung with lamellar and electron dense granules. An ultrastructural study. Cancer 1982; 50:2839-44

4 Fine G,Chang CH. Adenoma of type 2 pneumocytes with oncocytic features. Arch Pathol Lab Med 1991; 115:797-801

5 Fukuda T, Ohnishi Y, Kanai I, et al. Papillary adenoma of the lung. Histological and ultrastructural findings in two cases. Acta Pathol Jpn 1992; 42:56-61

6 Hegg CA, Flint A,Singh G Papillary adenoma of the lung. Am J Clin Pathol 1992; 97:393-7

7 Kurotaki H, Kamata Y, Kimura M, et al. Multiple papillary adenomas of type II pneumocytes found in a 13-year-old boy with von Recklinghausen's disease. Virchows Arch A Pathol Anat Histopathol 1993; 423:319-22

8 Mori M, Chiba R, Tezuka F, et al. Papillary adenoma of type II pneumocytes might have malignant potential. Virchows Arch 1996; 428:195-200

9 Noguchi M, Kodama T, Shimosato Y, et al. Papillary adenoma of type 2 pneumocytes. Am J Surg Pathol 1986; 10:134-9

10 Yamamoto T, Horiguchi H, Shibagaki T, et al. Encapsulated type II pneumocyte adenoma: a case report and review of the literature. Respiration 1993; 60:373-7



This page last revised 31.3.2005.

©SMUHT/PW Bishop