Lesions of the nasal cavity (NC) and paranasal sinuses (PNS) constitute a diverse group of pathological entities ranging from inflammatory and benign proliferations to aggressive malignant tumours. Although cancers of the NC and PNS are rare, accounting for less than 1% of all malignancies worldwide and approximately 3% of all head and neck cancers, they pose significant diagnostic and therapeutic challenges due to their complex anatomy and varied histopathology [1,2]. Globally, the incidence of sinonasal malignancies shows geographic variation, with higher rates reported in certain regions of Asia and Africa, influenced by environmental, occupational, and lifestyle factors [3]. In India, while data are limited, studies indicate that sinonasal tumours form an important subset of head and neck cancers, contributing to morbidity due to late presentation and diagnostic dilemmas [4,5]. The varied clinical presentations, such as nasal obstruction, epistaxis, facial swelling, and anosmia, are often nonspecific and overlap among inflammatory, benign, and malignant conditions, complicating clinical diagnosis [6]. Imaging modalities including computed tomography (CT) and magnetic resonance imaging (MRI) assist in assessing the lesion's extent, involvement of adjacent structures, and bone erosion but lack specificity in differentiating benign from malignant lesions or in identifying subtle histopathological differences [7]. Histopathological examination remains the gold standard for definitive diagnosis, enabling accurate classification of lesions, differentiation between neoplastic and non-neoplastic processes, and identification of tumour grade and subtype. This is crucial because management strategies and prognoses differ significantly between these entities. For example, benign lesions like nasal polyps require conservative management, whereas malignant tumours such as squamous cell carcinoma demand aggressive multimodal treatment [8]. In the Indian context, a spectrum of studies has highlighted the predominance of inflammatory and benign lesions among nasal cavity specimens, but also underscore a substantial proportion of malignant tumours, especially squamous cell carcinoma, adenocarcinoma, and less common types like esthesioneuroblastoma and sinonasal undifferentiated carcinoma [4,5,8]. Moreover, a considerable diagnostic challenge lies in recognizing non-neoplastic mimickers of neoplasia, such as fungal infections and granulomatous diseases, which necessitate distinct therapeutic approaches [6]. Thus, this study aims to provide a comprehensive histopathological evaluation of both non-neoplastic and neoplastic lesions of the nasal cavity and paranasal sinuses encountered in a tertiary care setting, emphasizing the clinicopathological correlation and the diagnostic challenges involved. Such data are essential for guiding clinical management, improving patient outcomes, and formulating region-specific diagnostic and therapeutic protocols. Aim: To evaluate the histopathological spectrum of non-neoplastic and neoplastic lesions of the nasal cavity and paranasal sinuses and correlate them with clinical presentations in a tertiary care centre. Objectives 1. To categorize and analyse the different types of non-neoplastic and neoplastic lesions of the nasal cavity and paranasal sinuses based on histopathological examination. 2. To assess the clinicopathological correlation between clinical diagnosis and histopathological findings in nasal cavity lesions and paranasal sinuses.

Study Design and Setting This was a retrospective descriptive study conducted in the Department of Pathology, Basaveshwara Medical College and Hospital, Chitradurga, Karnataka, India. The study was carried out over a defined period of 2 years, during which 150 cases of nasal cavity (NC) and paranasal sinus (PNS) lesions were examined histopathologically. Relevant clinical and radiological data were retrieved from patient case records and requisition forms submitted with the histopathology specimens. Sample Size A total of 150 cases of lesions involving the nasal cavity and paranasal sinuses were included in the study. These comprised both biopsies (incisional) and surgical resection specimens submitted to the pathology department. Sampling Method All eligible cases received within the specified study period were included consecutively, meeting the inclusion criteria, ensuring a comprehensive dataset for analysis. Inclusion Criteria • All biopsies and surgical specimens (incisional or excisional) obtained from lesions originating in the nasal cavity or paranasal sinuses. • Specimens showing inflammatory, infectious, benign, or malignant pathology on histopathological examination. • Availability of adequate tissue in paraffin blocks and slides for review. • Complete clinical details including age, sex, presenting symptoms, clinical diagnosis, and available radiological findings. Exclusion Criteria • Poorly preserved or inadequate tissue samples not suitable for evaluation. • Samples showing only necrosis or haemorrhage with no viable tissue for diagnosis. • Lesions extending from adjacent regions such as the orbit or nasopharynx without primary origin in the nasal cavity or paranasal sinuses. • Incomplete clinical or radiological data, or cases with missing slides/blocks. Data Collection The following data were collected from case files and pathology records: • Demographic details: Age and sex of the patients. • Clinical history: Duration and type of symptoms (nasal obstruction, epistaxis, nasal mass, discharge, anosmia, etc.). • Clinical diagnosis: Preliminary clinical impression at the time of biopsy. • Histopathological examination details Specimen Processing and Histopathological Examination details • All specimens were fixed in 10% neutral buffered formalin, processed routinely, and embedded in paraffin wax. • Sections of 4–5 µm thickness were cut using a rotary microtome and stained with Haematoxylin and Eosin (H&E) for routine histopathological examination. • Slides were independently reviewed and evaluated under a light microscope by at least two pathologists to reach a final consensus diagnosis. Classification and Grouping of Lesions Histologically, the lesions were broadly categorized into: 1. Non-Neoplastic Lesions o Inflammatory polyps o Chronic rhinosinusitis o Fungal sinusitis (e.g., mucormycosis, aspergillosis) o Granulomatous diseases (e.g., tuberculosis, rhinosporidiosis, rhinoscleroma) o Other inflammatory or hypertrophic conditions 2. Neoplastic Lesions o Benign tumours: e.g., inverted papilloma, haemangioma o Malignant tumours: e.g., squamous cell carcinoma, adenocarcinoma, olfactory neuroblastoma, sinonasal undifferentiated carcinoma (SNUC), non-Hodgkin lymphoma Statistical Analysis Data were compiled using Microsoft Excel and statistically analysed using SPSS software. Descriptive statistics such as frequency, percentage, mean, and standard deviation were used to summarize demographic and clinical data. Clinicopathological correlation was assessed by comparing the initial clinical diagnosis with final histopathological diagnosis. The Chi-square test was used to assess statistical significance in correlation, and a p-value < 0.05 was considered significant.

In the present study age of patients ranged from 11 years to 78 years with a M:F ratio of 1.8:1. On histopathological examination (HPE), in our study out of 150 cases, non-neoplastic lesions occupied 81.33% (122 cases) out of which most common lesion was sinonasal polyp 51% (76 cases) and its most common presenting symptom was nasal obstruction, benign neoplasms held 16.66% (25 cases) and the most common entity was inverted papilloma 7.33% (11 cases) and haemangioma 6.66% (10 cases) with epistaxis being the commonest presenting symptom and malignant lesions were only 2% (3 cases). Table 1: Distribution of Non-Neoplastic Lesions by Gender, Location, and Age (n = 76) Lesion NC Location (M) NC Location (F) PNS Location (M) PNS Location (F) Total Cases Age 0–20 Age 21–40 Age 41–60 Rhinoscleroma 4 2 0 0 6 0 5 1 Rhinosporidiosis 2 3 0 1 6 0 3 3 Rhinosinusitis 6 5 2 3 16 6 4 6 Tuberculosis 1 0 0 0 1 0 1 0 Aspergillosis 3 1 4 0 8 2 4 2 Mucormycosis 2 2 6 0 10 3 4 3 Sinonasal polyp 45 21 10 7 76 10 50 16 Observations: Sinonasal polyps were the most common lesion (76 cases), with a peak in the 21–40 age group (50 cases), and a male predominance (66 out of 76 cases). Mucormycosis was primarily located in the paranasal sinuses (6 male cases), and most frequently seen in younger to middle-aged adults. Rhinosinusitis showed a relatively even age distribution and was slightly more common in males. Rhinoscleroma and rhinosporidiosis were confined to the nasal cavity and were more common in males. Fungal infections (aspergillosis and mucormycosis) had a notable preference for paranasal sinuses, with aspergillosis also showing a male preponderance. Table 2: Distribution of Inflammatory, Benign, and Malignant Lesions in Nasal cavity and Paranasal Sinuses (n = 150) Category Type of Lesion Number of Cases Percentage (%) Nasal Paranasal Inflammatory (n = 126) Sinusitis 16 10.66 11 5 Mucormycosis 10 6.66 3 7 Rhinosporidiosis 6 4.00 5 1 Rhinoscleroma 6 4.00 6 0 Aspergillosis 7 4.66 5 2 Tuberculosis 1 0.66 1 0 Sinonasal polyp 76 50.66 19 57 Inferior turbinate hypertrophy 4 2.66 4 0 Benign (n = 21) Hemangioma 10 6.66 10 0 Inverted papilloma 11 7.33 10 1 Malignant (n = 3) Squamous cell carcinoma 1 0.66 1 0 Undifferentiated carcinoma 1 0.66 1 0 Olfactory neuroblastoma 1 0.66 0 1 Total 150 100.00 77 73 Figure 1: Distribution of Inflammatory, Benign, and Malignant Lesions in Nasal cavity and Paranasal sinuses (n = 150) Table 3: Overall Distribution of Lesions by Nature Type of Lesion Number of Cases Percentage (%) Inflammatory 126 84.00 Benign 21 14.00 Malignant 3 2.00 Total 150 100.00 Observations: Inflammatory lesions made up the vast majority (84%) of cases, with sinonasal polyps (50.66%) being the most prevalent individual entity. Fungal infections, including aspergillosis and mucormycosis, constituted a significant portion (11.32%) of inflammatory lesions, highlighting the need for high clinical suspicion, especially in immunocompromised individuals. Benign tumors accounted for 14%, with inverted papilloma (7.33%) being slightly more frequent than hemangioma (6.66%). Malignancies were rare in this dataset (only 2%)—notably, squamous cell carcinoma, undifferentiated carcinoma, and olfactory neuroblastoma, each accounting for 0.66% of cases. The distribution between nasal (77 cases) and paranasal (73 cases) locations was relatively balanced, with nasal cavity slightly more involved in benign and malignant lesions. Table 4: Distribution of Clinical Presentations (n = 150) Clinical Presentation Number of Cases Percentage (%) Nasal obstruction 60 40.00 Fever, headache & runny nose 35 23.33 Epistaxis 16 10.66 Nasal mass 14 9.33 Breathing difficulty 11 7.33 Decreased smell (hyposmia/anosmia) 11 7.33 Foul-smelling nasal discharge 2 1.33 Change in voice 1 0.66 Total 150 100.00 Fig 2: Distribution of Clinical Presentations (n = 150) Observations: The most common symptom was nasal obstruction, seen in 40% of patients, followed by fever, headache, and runny nose (23.33%). Epistaxis and nasal mass were also notable presenting features, especially in neoplastic conditions. Less common symptoms included foul-smelling discharge, change in voice, and decreased smell, which may be seen in both chronic inflammatory and neoplastic conditions. These findings underscore the non-specific and overlapping nature of clinical presentations in nasal cavity and paranasal sinus lesions, further reinforcing the importance of histopathological diagnosis.

Lesions of the nasal cavity (NC) and paranasal sinuses (PNS) represent a wide spectrum of pathological conditions ranging from simple inflammatory processes to complex neoplastic lesions, both benign and malignant. In the present study involving 150 cases, inflammatory lesions formed the majority, accounting for 84% of all cases, with benign and malignant neoplastic lesions comprising 14% and 2%, respectively. Fig 1a: Inflammatory polyp consisting of mixed inflammatory cells, including lymphocytes, plasma cells, eosinophils & neutrophils. (H&E, X 40) Fig 1b: Inflammatory polyp showing edematous, fibrotic or loosely myxoid stroma covered by respiratory epithelium. (H&E, X 40) This significant predominance of inflammatory pathology is in concordance with prior Indian and international studies. Sinonasal polyps emerged as the most common lesion in our study (50.66%), consistent with findings by Kamath et al. [9], who reported a similarly high incidence of inflammatory nasal polyps in their analysis. Sharma et al. [10] and Bist et al. [11] also reported a predominance of non-neoplastic lesions in the sinonasal tract, underlining the high burden of chronic inflammation in the upper airway mucosa. Chronic rhinosinusitis (10.6%), mucormycosis (6.6%), aspergillosis (4.6%), and granulomatous infections like rhinoscleroma, rhinosporidiosis, and tuberculosis were notable findings in our inflammatory group. The increased frequency of fungal sinusitis, particularly mucormycosis, in the PNS region (7 out of 10 cases), may be linked to comorbidities like uncontrolled diabetes, immunosuppression, or recent viral epidemics (e.g., COVID-19), as documented by Panda et al. [12]. This growing trend of fungal infections, especially in tropical climates and urban hospitals, has significant implications for diagnosis and early intervention. Granulomatous diseases such as rhinoscleroma and rhinosporidiosis, although rare globally, were notable in our study (4% each), especially in male patients. These are chronic infections endemic to certain parts of India and Southeast Asia, and their clinical presentations often mimic neoplasms, necessitating careful histopathological evaluation. Similar observations were made by Maheshwari et al. [13] and Chavan et al. [14], who emphasized the importance of differentiating these entities from malignancies through histopathology and special stains like PAS and ZN. Among benign neoplasms, inverted papilloma was the most common (7.3% of total cases), followed by haemangioma. Inverted papilloma is a locally aggressive tumor with a propensity for recurrence and occasional malignant transformation, a pattern also observed by Prakash et al. [15]. These tumours frequently involve the nasal cavity and lateral wall, as observed in our series. Capillary haemangiomas were seen exclusively in nasal sites, presenting with epistaxis, and their diagnosis was confirmed histologically. Fig 2a: Oncocytic papilloma with endophytic (inverted) growth pattern (H&E, X10) Fig 2b: Epithelium lined by pseudostratified and columnar with abundant eosinophilic granular cytoplasm and hyperchromatic uniform nuclei. (H&E X 40) Fig 3a: Shows Undifferentiated carcinoma on low magnification. (H&E, X 20) Fig 3b: Areas of necrosis and inflammatory cell infiltrate seen (H&E, X 10) Malignant tumours constituted a small portion of cases (2%), with squamous cell carcinoma, olfactory neuroblastoma, and undifferentiated carcinoma each contributing a single case. Though small in number, these entities are clinically significant due to their aggressive nature, late presentation, and complex treatment protocols. Similar diagnostic challenges and patterns were reported in the studies by Garg et al. [16] and Dutta et al. [17], who emphasized the vital role of histopathology in distinguishing between morphologically similar malignant entities like olfactory neuroblastoma and sinonasal undifferentiated carcinoma (SNUC), especially with the aid of immunohistochemistry (IHC). Regarding age distribution, the peak incidence of lesions was seen in the 21–40-year age group, particularly among inflammatory and benign neoplastic cases. Males were more frequently affected than females, with a male-to-female ratio of approximately 1.6:1. This male predominance has been attributed to greater occupational exposure to allergens, dust, and industrial pollutants, as documented in studies by Sharma et al. [10] and Maheshwari et al. [13]. The most common clinical presentation was nasal obstruction (40%), followed by fever/headache/runny nose (23.3%) and epistaxis (10.6%). These symptoms were nonspecific and often overlapped between benign and malignant pathologies, highlighting the importance of histopathological confirmation for accurate diagnosis. Fig 5: Malignant squamous cells seen in squamous cell carcinoma (H&E, X 40) Overall, the present study supports the findings of prior literature, reinforcing that histopathology remains the gold standard for the diagnosis and classification of nasal and paranasal sinus lesions. It not only provides a definitive diagnosis but also guides further management, particularly in distinguishing mimickers like fungal infections from true neoplasms.

The present study highlights the diverse pathological spectrum of nasal cavity and paranasal sinus lesions, with inflammatory conditions forming the majority, followed by benign and rare malignant neoplasms. Sinonasal polyps were the most frequent lesion, underscoring the burden of chronic inflammatory diseases in the upper respiratory tract. The occurrence of fungal infections like mucormycosis draws attention to emerging infectious trends requiring timely diagnosis and management. Although malignant tumours were uncommon, their aggressive nature mandates early histopathological identification. Overall, this study reinforces the pivotal role of histopathology in establishing definitive diagnoses, facilitating appropriate clinical interventions, and improving patient outcomes.

1. Gedam PK, Chawhan SM, Chawhan SS, Pandhare ML. Histopathological Study of Lesions of Nasal Cavity and Paranasal Sinuses. J Med Sci Health. 2022;8(1):65-72. 2. Garg D, Mathur K. Clinico-pathological Study of Space Occupying Lesions of Nasal Cavity, Paranasal Sinuses and Nasopharynx. J Clin Diagn Res. 2014 Nov;8(11):FC04-7. 3. Dutta V, Mahajan A, Agarwal N, Singh P. Epidemiology and clinicopathological profile of sinonasal malignancies: a review of Indian data. Indian J Cancer. 2020;57(1):52-7. 4. Khan N, Zafar U, Afroz N, Ahmad SS, Hasan SA. Masses of nasal cavity, paranasal sinuses and nasopharynx: A clinicopathological study. Indian J Otolaryngol Head Neck Surg. 2006 Jul;58(3):259-63. 5. Kumari S, Pandey S, Verma M, Rana AK, Kumari S. Clinicopathological Challenges in Tumours of the Nasal Cavity and Paranasal Sinuses: Our Experience. Cureus. 2022 Sep 13;14(9):e29128. 6. Singh N, Sharma R, Kapoor R. Spectrum of non-neoplastic lesions of nasal cavity and paranasal sinuses: a clinicopathological study from North India. Int J Otorhinolaryngology Head Neck Surg. 2019;5(3):655-9. 7. Patel M, Patel N, Chauhan D. Role of Imaging in Sinonasal Lesions. Int J Otolaryngol Head Neck Surg. 2017;6(3):81-7. 8. Gupta M, Sharma M, Bhatia A. Histopathological spectrum of sinonasal masses: a study of 120 cases from a tertiary care hospital in India. J Clin Diagn Res. 2018;12(7):EC14-8. 9. Kamath PM, Rao D, Kamboj M. Histopathological spectrum of nasal cavity lesions: A 5-year study. Indian J Pathol Oncol. 2017;4(3):456–461. 10. Sharma R, Sood A, Gupta AK, Singh H. Clinicopathological study of nasal and paranasal sinus lesions. Int J Otorhinolaryngol Head Neck Surg. 2018;4(2):457–462. 11. Bist SS, Varshney S, Baunthiyal V, Bhagat S, Kusum A. Spectrum of sinonasal lesions: A clinicopathological study. Indian J Otolaryngol Head Neck Surg. 2019;71(Suppl 2):1583–1589. 12. Panda NK, Sharma SC, Chakravarti A, Lal P. Fungal sinusitis: Changing trends and new insights. Indian J Otolaryngol Head Neck Surg. 2018;70(3):435–441. 13. Maheshwari V, Jain A, Alam K, Khan R, Singh M, Sharma SC. Histopathological profile of nasal cavity and paranasal sinus lesions: A tertiary care experience. J Clin Diagn Res. 2020;14(3):EC01–EC05. 14. Chavan SS, Mohite A, Waghmare A, Bhosale P. Spectrum of sinonasal lesions with clinicopathological correlation: A 5-year study. J Clin Pathol Res. 2021;5(1):12–18. 15. Prakash S, Kaur R, Kumar P, Chauhan S. Histopathological evaluation of benign sinonasal tumours: An institutional study. Indian J Pathol Microbiol. 2019;62(4):555–560. 16. Garg R, Rawat DS, Singh J. Clinicopathological profile of nasal cavity neoplasms: A retrospective study. Int J Res Med Sci. 2020;8(7):2594–2599. 17. Dutta V, Mahajan A, Agarwal N, Singh P. Epidemiology and clinicopathological profile of sinonasal malignancies: A review of Indian data. Indian J Cancer. 2020;57(1):52–57.