What are the differential diagnoses of a painful intranasal lesion?

Differential Diagnosis of Painful Intranasal Lesion

A painful intranasal lesion requires immediate consideration of invasive fungal sinusitis in immunocompromised patients, followed by systematic exclusion of neoplastic disease, granulomatous conditions, and infectious etiologies based on patient risk factors and clinical presentation.

Critical Life-Threatening Diagnoses to Exclude First

Invasive Fungal Sinusitis

• Painless nasal septal necrosis is the classical presentation, but pain can occur with tissue destruction 1, 2
• Occurs almost exclusively in immunocompromised patients: diabetes mellitus, hematologic malignancies, high-dose steroid therapy, neutropenia, or chronic renal failure 1, 2
• Early lesions may appear brick red or as black necrotic areas on endoscopy; the "black turbinate sign" indicates tissue necrosis 1
• Mortality rates reach 50-80% without urgent intervention—this diagnosis cannot be missed 1
• Rapidly progresses to fever, facial pain, proptosis, ophthalmoplegia, and potential CNS extension 1
• Immediate biopsy with fungal staining and culture is mandatory if suspected 1

Malignant Neoplasms

• Any unilateral painful intranasal lesion warrants consideration of malignancy, particularly squamous cell carcinoma 1
• Early signs are nonspecific: nasal obstruction, pain, rhinorrhea, and anosmia 1
• Pain suggests more aggressive behavior than benign lesions 1
• Other malignancies include sinonasal undifferentiated carcinoma, adenocarcinoma, lymphoma, melanoma, and esthesioneuroblastoma 1, 3
• Tissue biopsy is invaluable for definitive diagnosis, as clinical and radiographic findings alone are unreliable 1
• Unilateral presentation strongly favors neoplasm over inflammatory polyps 3, 4

Benign Neoplastic Lesions

Inverted Papilloma

• Most common benign sinonasal tumor with characteristic polypoid appearance and unilateral location 1
• Can cause pain through obstruction and secondary infection 1
• Requires biopsy for diagnosis and has malignant transformation potential 1

Juvenile Nasopharyngeal Angiofibroma

• Critical caveat: occurs only in adolescent/preadolescent males with vascular posterior nasal mass 1
• Never biopsy this lesion due to risk of catastrophic hemorrhage—diagnosis is clinical and radiographic 1
• Can present with pain, epistaxis, and nasal obstruction 1

Granulomatous Diseases

Granulomatosis with Polyangiitis (GPA/Wegener's)

• Characterized by granulomatous inflammation, necrosis, and vasculitis affecting small-to-medium vessels 1
• Nasal biopsy may show "consistent with" rather than definitive GPA, as all three criteria (necrosis, granulomas, vasculitis) must be present 1
• Progressive loss of midfacial structures can mimic NK/T cell lymphoma 1
• c-ANCA testing supports diagnosis, but tissue confirmation is preferred for localized disease 1

Other Granulomatous Conditions

• Sarcoidosis, tuberculosis, rhinoscleroma, fungal diseases (rhinosporidiosis), and other autoimmune conditions 1, 5
• Nasal-sinus biopsy should be obtained when granulomatous disease is suspected but diagnosis unclear 1

Infectious Etiologies

Acute Bacterial Rhinosinusitis with Complications

• Pain suggests potential periosteal involvement or early abscess formation 1
• Purulent nasal drainage with facial pain-pressure-fullness for >10 days or worsening symptoms after initial improvement 1
• Complications include orbital cellulitis, subperiosteal abscess, or intracranial extension 1

Non-Invasive Fungal Disease

Fungus Ball

• Typically maxillary or sphenoid sinus, unilateral presentation with chronic symptoms 2, 6
• Pain occurs from pressure necrosis as mass impinges on surrounding structures 2
• Dense accumulations of hyphae without eosinophilic mucin on histology 2

Allergic Fungal Sinusitis

• Occurs in immunocompetent atopic patients, typically bilateral 2
• Pain less common; presents more with chronic congestion and nasal polyps 2
• Unilateral disease with facial deformity can occur in children 2

Diagnostic Algorithm

Step 1: Assess Immune Status Immediately

• If immunocompromised (diabetes, malignancy, steroids, neutropenia): assume invasive fungal sinusitis until proven otherwise 1, 2
• Obtain urgent ENT consultation and biopsy with fungal staining 1

Step 2: Determine Laterality

• Unilateral lesions demand higher suspicion for malignancy or fungus ball 1, 2, 3
• Bilateral lesions favor inflammatory polyps or allergic fungal sinusitis 2, 3

Step 3: Obtain Appropriate Imaging

• CT maxillofacial is first-line to assess bony changes: remodeling suggests benign, lytic destruction suggests malignancy 1
• MRI with contrast if concern for orbital/intracranial extension, vascular involvement, or to differentiate tumor from inflammation 1, 6

Step 4: Endoscopic Examination and Biopsy

• Direct visualization with nasal endoscopy to assess lesion characteristics 1, 6
• Biopsy is essential for any suspicious lesion—send for routine histology, fungal staining, and culture 1
• Exception: do not biopsy suspected juvenile angiofibroma in young males 1

Step 5: Consider Systemic Workup

• c-ANCA/p-ANCA if granulomatous disease suspected 1
• Serum IgE and fungal skin testing if allergic fungal sinusitis considered 2
• Chest imaging if GPA or sarcoidosis suspected 1

Common Pitfalls to Avoid

• Never assume a painful intranasal lesion is "just sinusitis" without excluding malignancy and invasive fungal disease 1
• Do not delay biopsy in immunocompromised patients—early diagnosis of invasive fungal sinusitis is critical for survival 1
• Unilateral presentation always warrants tissue diagnosis regardless of appearance 1, 3
• Plain radiographs are inadequate—use CT or MRI for proper evaluation 1
• Nasal cavity cultures do not correlate with sinus aspirate cultures and should not guide diagnosis 1