--- title: "Signs in Nasal Mass | Dodd Sign, Double Density Sign & Furstenberg Sign" description: "ENT notes on Dodd Sign, Double Density Sign and Furstenberg Sign." source: "The ENT Resident" author: "Dr. Mausumi Das" canonical_url: "https://www.theentresident.com/ent-notes-lectures/double-density-sign-dodd-sign-furstenberg-sign" categories: ["Signs, Syndromes, Triads, and Compilation Lists in ENT", "Rhinology"] video: "https://www.youtube.com/watch?v=65m9bffhpDQ" image: "https://media.theentresident.com/og-images/double-density-sign-dodd-sign-furstenberg-sign.png" --- # Signs in Nasal Mass | Dodd Sign, Double Density Sign & Furstenberg Sign ENT notes on Dodd Sign, Double Density Sign and Furstenberg Sign. Watch the full video lecture on YouTube: https://www.youtube.com/watch?v=65m9bffhpDQ ## 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. --- ## About This Note This free ENT note on Signs in Nasal Mass | Dodd Sign, Double Density Sign & Furstenberg Sign was written by Dr. Mausumi Das and is paired with a corresponding video lecture. 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