Papillomas and adenomas

Squamous / glandular / mixed papilloma

Last author update: 1 January 2016
Last staff update: 7 June 2023

Copyright: 2003-2023,, Inc.

PubMed Search: Squamous papilloma [title]

Roseann I. Wu, M.D., M.P.H.
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Cite this page: Wu R. Squamous / glandular / mixed papilloma. website. Accessed September 29th, 2023.
Definition / general
  • Solitary endobronchial papillomas in adults is rare, < 0.5% of lung tumors
  • Squamous papillomas usually occur in middle aged male smokers
  • Also called squamous cell papilloma, solitary tracheobronchial papilloma
  • Termed papillomatosis if multiple lesions present
Clinical features
  • Associated with HPV 6 and HPV 11; high risk HPV may be seen in cases associated with carcinoma (Hum Pathol 1994;25:1191)
  • Noninvasive but may have dysplasia, recur or develop into squamous cell carcinoma
  • Nonspecific lower respiratory tract complaints include hemoptysis, recurrent pneumonia, asthma-like symptoms, dry cough
  • Rarely arises in lower bronchial tree, but usually manifests as endobronchial exophytic growth
  • May be difficult on frozen section and small biopsy specimens to distinguish from squamous carcinoma
Radiology description
  • May be incidental finding on imaging or show symptoms related to obstruction
  • Xray: either normal, infiltrative shadow, hilar mass or lobar collapse
  • CT: mass shadowing, can be PET avid
Radiology images

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Pedunculated mass

Pedunculated mass

Case reports
  • Endoscopic removal, cryotherapy, fulguration
  • Surgical resection
Gross description
  • Tan-white, friable, pedunculated / polypoid, smooth to verrucoid, glistening
  • Wart-like, cauliflower-like
  • Generally less than a few centimeters in size
Microscopic (histologic) description
  • Usually exophytic, papillary lesion with arborizing fibrovascular cores lined by keratinizing or nonkeratinizing mature squamous epithelium
  • Rarely inverted pattern
  • Lesion may grow into adjacent alveolar spaces
  • May contain areas lined by ciliated or non-ciliated columnar cells with cuboidal cells or mucin-filled cells (mixed squamous and glandular papilloma)
  • May exhibit viral cytopathic effect: enlarged hyperchromatic nuclei, nuclear wrinkling, polychromasia, binucleate forms, perinuclear halos
  • Mild to moderate stromal inflammation which may be related to airway obstruction
  • No mitoses, no necrosis
Microscopic (histologic) images

Contributed by Roseann Wu, M.D., M.P.H.

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Various images

Various images

Solid mass

Solid mass

Schneiderian papilloma

Schneiderian papilloma

Bronchiak papilloma

Bronchial papilloma

Cytology description
  • Moderate cellularity, single and loosely clustered squamous cells
  • Cytoplasmic keratinization and dark pyknotic nuclei with variable atypia, may show cells resembling koilocytes
  • Background acute inflammation
Cytology images

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Positive stains
Negative stains
Molecular / cytogenetics description
  • Subset positive for HPV by ISH or PCR
Differential diagnosis
Additional references
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