Signs in Nasal Mass | Dodd Sign, Double Density Sign & Furstenberg Sign
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Dodd Sign, Double Density Sign & Furstenberg Sign
Dodd Sign
📌 Type of Sign
👉 Radiological Sign seen on X-ray Nasopharynx (Lateral view).
What is the other name for Dodd sign?
🔍 What is the Sign?
Dodd Sign refers to a crescent of air between a nasopharyngeal mass and the posterior pharyngeal wall.
Seen in Antrochoanal Polyp.
🧠 Why Does it Occur?
When a nasopharyngeal mass has not arisen from the posterior wall, a thin air space remains behind the mass, forming a crescent shaped radiolucent area.
⭐ A positive Dodd Sign means the nasopharyngeal mass is separate from the posterior wall.
An antrochoanal polyp originates from the antrum of the maxillary sinus, reaches the choana and hangs freely in it. As it does not arise from the posterior wall, a crescent of air remains behind it.
👨⚕️ Eponym
Named after Dodd, who described this air crescent appearance behind an antrochoanal polyp on a lateral radiograph.
What is the clinical importance of Dodd Sign?
Double Density Sign
📌 Type of Sign
👉 Radiological Sign seen on CT Paranasal Sinuses (Non-contrast).
🔍 What is the Sign?
Double Density Sign refers to a hyperdense area within an opacified sinus, contrasting with the surrounding inflamed mucosa.
Seen in Allergic Fungal Rhinosinusitis.
What does the hyperdense area represents in Double Density sign?
🧠 Why Does it Occur?
Normally, sinus secretions and mucosa appear as a greyish soft tissue density.
In allergic fungal rhinosinusitis, manganese and calcium deposits in the allergic fungal mucin produce intensely bright hyperdense shadows within the sinus.
🔍 Why is it Called Double Density Sign?
The sinus shows two different attenuation levels:Hypodense soft tissue density & Hyperdense concretions.
What is the most common sinus involved in allergic fungal rhinosinusitis?
⚖️ Allergic Fungal Rhinosinusitis vs Invasive Fungal Sinusitis
| Feature | Allergic Fungal Rhinosinusitis | Invasive Fungal Sinusitis |
|---|---|---|
| Bone destruction | Absent | Present |
| Immune status | Immunocompetent patients | Immunocompromised patients |
Furstenberg Sign
📌 Type of Sign
👉 Clinical Sign elicited during Examination of a nasal mass.
🔍 What is the Sign?
Furstenberg Sign refers to expansion of a nasal mass on crying, straining or compression of the jugular vein.
Seen In
- Encephalocele
- Meningocele
- Meningoencephalocele
🧠 Why Does it Occur?
In an encephalocele, intracranial contents herniate through the skull base into the nasal cavity, so the nasal mass contains intracranial content.
Crying, straining or Valsalva maneuver
→ Jugular vein compression
→ Increased intracranial venous pressure
→ Raised CSF pressure
→ Expansion of the encephalocele
👨⚕️ Eponym
Named after Furstenberg, who described this characteristic expansile pulsation of an encephalocele with raised intracranial pressure maneuvers.
What are the differences between Glioma & Encephalocele?
⭐ High Yield Rapid Revision Table
| Sign | Type | Finding | Seen In |
|---|---|---|---|
| Dodd Sign | Radiological (X-ray Nasopharynx, lateral view) | Crescent of air between the mass and posterior pharyngeal wall | Antrochoanal polyp |
| Double Density Sign | Radiological (CT PNS) | Hyperdense fungal mucin within an opacified sinus | Allergic fungal rhinosinusitis |
| Furstenberg Sign | Clinical | Expansion of nasal mass on crying, straining or jugular compression | Encephalocele, Meningocele, Meningoencephalocele |
🧠 Viva Pearls
- Dodd Sign is seen on a lateral X-ray of the nasopharynx.
- Positive Dodd Sign indicates that the nasopharyngeal mass is separate from the posterior wall.
- Antrochoanal polyp arises from the antrum of the maxillary sinus and hangs freely in the choana.
- Double Density Sign is seen on a non-contrast CT of the paranasal sinuses.
- Double Density Sign is due to manganese and calcium deposits in allergic fungal mucin.
- Allergic fungal rhinosinusitis occurs in immunocompetent patients; invasive fungal sinusitis occurs in immunocompromised patients.
- Furstenberg Sign is expansion of a nasal mass on crying, straining or jugular vein compression.
- Furstenberg Sign is seen in encephalocele, meningocele and meningoencephalocele.
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