Accretion and Excrescence-Papilloma Lung Volume 53- Issue 5

Anubha Bajaj*

• Consultant Histopathologist, A.B. Diagnostics, India

Received: November 15, 2023; Published: November 24, 2023

*Corresponding author: Anubha Bajaj, Consultant Histopathologist, A.B. Diagnostics, A-1, Ring Road, Rajouri Garden, New Delhi, India

DOI: 10.26717/BJSTR.2023.53.008471

Abstract PDF

Abbreviations: HPV: Human Papilloma Virus; PCR: Polymerase Chain Reaction; PET: Positron Emission Tomography; TTF-1: Thyroid Transcription Factor-1

Papilloma is a benign neoplasm emerging from epithelium layering the respiratory tract. Neoplasm incriminating the respiratory tract commonly arises within large bronchi and is frequently associated with tracheal or laryngeal lesions. Generally, papilloma manifests with distinct histologic subtypes as

• Squamous papilloma

• Glandular papilloma

• Mixed squamous and glandular papilloma.

Additionally designated as squamous cell papilloma or solitary tracheobronchial papilloma, multiple squamous papillomas may be scripted as papillomatosis. Papilloma confined to pulmonary parenchyma is frequently associated with epithelial metamorphosis as dysplasia, carcinoma in situ or invasive squamous cell carcinoma. Solitary endobronchial papilloma is exceptionally encountered in adults and configures below < 0.5% of pulmonary neoplasms. Commonly, squamous papilloma of lung incriminates middle aged subjects. A mild male predominance is observed. Individuals with history of tobacco consumption as cigarette smokers are preponderantly implicated [1,2]. Squamous papilloma of lung appears concurrent with lowrisk variants of human papilloma virus 6 and 11 [HPV 6 and HPV 11] Notwithstanding, high risk variants of human papilloma virus [HPV] are concordant with instances of pulmonary carcinoma [1,2].

Pre-eminently non-invasive, squamous papilloma may exhibit dysplasia, lesion reoccurrence or may progress into squamous cell carcinoma. Lesion is accompanied by nonspecific complaints arising from incrimination of lower respiratory tract as haemoptysis, repetitive bouts of pneumonia, asthma-like symptoms or dry cough. Exceptionally, lesion may incriminate lower bronchial tree and may manifest as an endobronchial, exophytic tumefaction [1,2]. Cytological smears appear moderately cellular and are comprised of singularly dispersed and dis-cohesive clusters of squamous epithelial cells. Constituent epithelial cells may depict intracytoplasmic keratinization and are pervaded with intensely stained, pyknotic nuclei demonstrating variable nuclear atypia. Besides, epithelial cells may appear reminiscent of koilocytes. Cellular component is admixed with an acute inflammatory cell exudate [3,4].

Grossly, a friable, pedunculated or polypoid, smooth to verrucoid, tan to grey/white, wart-like or cauliflower-like tumefaction with glistening surface is encountered. Tumour magnitude is beneath < few centimetres. Upon microscopy, an exophytic, papillary lesion is enunciated. Papillae are layered with keratinizing or non-keratinizing, mature squamous epithelium and infiltrated by arborizing cores of fibro- vascular tissue. Exceptionally, papillary structures may exhibit an inverted configuration. The expansive lesion may infiltrate adjacent alveolar spaces [3,4]. Alternatively, the cellular lesion may be layered by ciliated or non-ciliated columnar epithelium along with cuboidal epithelial cells or mucin-filled cells, thereby configuring a ‘mixed’ squamous and glandular papilloma. Lesion may exemplify a viral ‘cytopathic’ effect with epithelial cells pervaded with enlarged, hyperchromatic nuclei demonstrating nuclear wrinkling. Besides, binucleate cells with cytoplasmic polychromasia and perinuclear haloes may be enunciated. Surrounding stroma delineates mild to moderate infiltrate of inflammatory cells which may engender airway obstruction. Mitotic figures and tumour necrosis are absent [3-7] (Figures 1 & 2; Tables 1 & 2).

Figure 1

Figure 2

Table 1: Classification of Lung Tumours World Health Organization 2021 [2].

Table 2: Immunohistochemistry of nonsmall cell lung carcinoma [3].

Note: CK: cytokeratin, TTF-1: thyroid transcription factor-1

Papilloma lung appears immune reactive to squamous epithelial markers as p40 or CK5/6. Besides, lesion appears immune reactive to glandular markers as mucicarmine. Mixed squamous and glandular papilloma appears immune reactive to CK7. Lesion appears immune nonreactive to thyroid transcription factor-1 [TTF-1] and CK20. A subset of neoplasms appearreactive for human papilloma virus [HPV], as discerned by in situ hybridization [ISH] or polymerase chain reaction [PCR] [4,5]. Papilloma emerging within pulmonary parenchyma requires segregation from neoplasms such as inflammatory polyp, mucoepidermoid carcinoma or papillary squamous cell carcinoma [4,5]. Upon frozen section or examination of miniature tissue samples, papilloma lung may be challenging to discern or segregate from squamous epithelial carcinoma. Papilloma lung may be incidentally discovered upon cogent imaging studies. Alternatively, clinical symptoms concurrent with airway obstruction may ensue [4,5].

Plain radiographs may appear unremarkable or exhibit an infiltrative shadow or hilar tumefaction. Besides, lobar collapse may be discerned. Computerized tomography enunciates shadowing of the tumefaction. Upon positron emission tomography [PET] scan, tumour may depict avidity for 18F- fluorodeoxyglucose [18F-FDG] [4,5]. Papilloma arising within pulmonary parenchyma may be appropriately managed with endoscopic eradication of the lesion. Additionally, manoeuvers such as cryotherapy or fulguration may be adopted. Certain lesions may be optimally alleviated by surgical extermination of lesion [4,5].

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2. Andrew G Nicholson, Ming S Tsao, Mary Beth Beasley, Alain C Borczuk, Elisabeth Brambilla, et al. (2022) The 2021 WHO Classification of Lung Tumors Impact of Advances Since 2015. Journal of Thoracic Oncology 17(3): 362-387.
3. Anna Grodzka, Agnieszka Knopik Skrocka, Katarzyna Kowalska, Pawel Kurzawa, Monika Krzyzaniak, et al. (2023) Molecular alterations of driver genes in non-small cell lung cancer from diagnostics to targeted therapy. EXCLI J 22: 415-432.
4. Sai On Ling, Yiu Fai Cheng, Pak Yuen Anthony Yau, Chie Wai Yim, Hoi Yee Kwan, et al. (2023) Recurrent respiratory papillomatosis (RRP) of tracheobronchial tree presenting as lung collapse with malignant transformation after a decade. Respir Med Case Rep 45: 101904.
5. Amar Ahmed, Asmita Shukla, Natalie Hubbell, Mohamad Khaled Almujarkesh, Dana LaBuda, et al. (2023) Early Identification and Intervention in Malignant Transformation of Respiratory Papillomatosis. Am J Case Rep 10: 24.
6. Image 1 Courtesy: Wikimedia commons.
7. Image 2 Courtesy: Libre Pathology.