Cholesteatoma

🧠 Cholesteatoma

🌬 What is Cholesteatoma?

Cholesteatoma is defined as a benign sac of keratinizing squamous epithelium within the middle ear cleft that has bone-eroding property and lost its self-cleaning capacity.

What are the structures of the Middle Ear Cleft?

Why is keratinizing squamous epithelium abnormal in the middle ear?

Synonyms/Alternative Names:

• Keratoma: Signifying its keratin-filled nature.
• Epidermosis: Describing its origin from squamous epithelium.

Why is the term "Cholesteatoma" a misnomer?

🧱 Structure of a Cholesteatoma

A cholesteatoma essentially consists of two parts:

1. Matrix: This is the outer sac, composed of keratinizing squamous epithelium. It rests on a thin layer of fibrous stroma (submucosal connective tissue). The matrix is the living, actively growing part.

2. Central White Mass: This core consists of desquamated keratin debris (dead skin cells) that are continuously produced by the matrix. This accumulating keratin is what expands and causes pressure/erosion.

🧬 Theories of Cholesteatoma : Origin

Cholesteatoma can be classified by its origin: congenital or acquired.

Different theories explain how the keratinizing squamous epithelium enters the middle ear cleft.

📚 Mnemonic to remember Theories of Cholesteatoma : REAL BIG EARS MAKE ECHOES

• Retraction Pocket (Wittmaack's Theory)
• Basal cell hyperplasia (Ruedi's Theory)
• Epithelial migration (Habermann's Theory)
• Metaplasia (Sade's Theory)
• Embryonic cell rests (Congenital Cholesteatoma)

1. Congenital Cholesteatoma

• Definition: An expanding cystic mass of keratinizing squamous epithelium located medial to an intact tympanic membrane.

• Theory: Persistence of embryonic epidermal cell rests

What is Levenson's criteria for Congeintal Cholesteatoma?

• Common Sites: Middle ear, Petrous Apex, Cerebellopontine Angle (CPA)

What is the most common site for Congenital Cholesteatoma?

• Clinical Features:
  • Pearly white mass behind an intact TM
  • Conductive hearing loss.

What is the staging of Congenital Choelsteatoma?

2. Acquired Cholesteatoma

This type forms after birth due to various pathological processes.

It's further divided into primary and secondary.

A. Primary Acquired Cholesteatoma

• No prior history of otitis media, pre-existing perforation, or otorrhea.

• Theories of Origin:

  • Wittmaack's Theory (Invagination Theory / Retraction Pocket Theory)
  • Ruedi's Theory (Basal Cell Hyperplasia Theory)
  • Sade's Theory (Squamous Metaplasia Theory)

B. Secondary Acquired Cholesteatoma

• Occurs in the presence of a pre-existing TM perforation (usually posterior superior marginal or large central).

• Theories of Origin:

  • Habermann's Theory (Epithelial Invasion/Migration Theory)
  • Sade's Theory (Squamous Metaplasia Theory)

What is Wittmack's Retraction Pocket Theory?

What is Ruedi's Basal Cell Hyperplasia Theory?

What is Sade's Squamous Metaplasia Theory?

What is Habermann's Epithelial Invasion/Migration Theory?

🦴 Bone Destruction by Cholesteatoma

Cholesteatoma has a unique ability to destroy bone in its path (ossicles, bony labyrinth, facial nerve canal, sinus plate, tegmen tympani), leading to serious complications.

• Discarded Theory: Pressure Theory

• Current Theory: Enzymatic Theory.

What is Pressure Theory? Why has it been discarded now?

What is Enzymatic theory of bone destruction by Cholesteatoma?

What is the most common bone eroded by Cholesteatoma? Why?

Growth Pattern and Spread of Cholesteatoma

Cholesteatoma typically spreads in predictable patterns based on its origin site:

1. Posterior Epitympanum Cholesteatoma: Spreads via:

• Anterior Pouch of von Troeltsch → Anterior Epitympanum → Supratubal Recess/Anterior Epitympanic Sinus.

• Posterior Pouch of von Troeltsch → Posterior Mesotympanum → Sinus Tympani/Round Window area/Facial Recess.

• Lateral Malleal/Incudal Folds → Superior Incudal Space/Lateral Attic → Aditus ad Antrum → Antrum → Mastoid.

1. Posterior Mesotympanum (Inferior Incudal Space) Cholesteatoma: Spreads via:

• Direct spread to Sinus Tympani and Facial Recess (most common).

• Posterior Tympanic Isthmus → Medial Attic (epitympanum medial to incus body).

• Posterior Pouch of von Troeltsch → Prussak's space → Superior Incudal Space → Aditus → Antrum → Mastoid.

1. Anterior Epitympanum Cholesteatoma: Spreads via:

• Superiorly to Tegmen Tympani/Dura/Middle Cranial Fossa.

• Anteriorly to Zygomatic Root Cells.

• Can involve Geniculate Ganglion and Facial Canal.

• Long-standing cases can cause Labyrinthine Fistula.

🦠 Microorganisms in Cholesteatoma

Polymicrobial.

• Pseudomonas aeruginosa
• Streptococcus
• Proteus
• E.coli
• Bacteroides
• Peptococcus
• Fusobacteria

What is the most common organism involved in Cholesteatoma?

👶 Pediatric vs Adult Cholesteatoma

Differences in presentation and behavior:

1. Extent of Spread: Pediatric cholesteatoma spreads more extensively through the temporal bone than in adults, with more involvement of perilabyrinthine cells and petrous apex.

2. Aggressiveness: Pediatric cholesteatoma is generally more aggressive due to the more pneumatized (air-filled) temporal bone, allowing easier and more extensive spread.

3. Inflammatory Response: Greater inflammatory response in children, with increased expression of markers like metalloproteinases and antibodies, leading to more bone erosion.

4. Labyrinthine Invasion: Less common in pediatric cases compared to adults.

5. Lateral Semicircular Canal Fistula/Fallopian Canal Erosion: Less common in pediatric cases.

6. Ossicular Erosion: More common in pediatric cholesteatoma.

📋 Clinical Features of Cholesteatoma

Cholesteatoma presents as a "dangerous" form of chronic otitis media (atticoantral type).

Symptoms:

• Ear Discharge (Otorrhea):

  • Persistent, Foul smelling, Purulent.Often blood stained.

  • Quantity: Typically SCANTY (as opposed to profuse in mucosal type).

  • Continuity: Usually Continuous

Why is ear discharge in Cholesteatoma foul smelling and blood stained?

Why is ear discharge in Cholesteatoma scanty and continuous?

Why is sudden cessation of discharge in Cholesteatoma an ominous sign?

• Hearing Loss: Mostly Conductive Hearing Loss (CHL). Can have an SNHL component.

What is Cholesteatoma Hearer?

• Bleeding from Ear: Due to friable granulation tissue or polyps, especially on cleaning.

• Other Symptoms (Indicating Complications): Patients often present with symptoms of complications due to bone erosion:

  • Pain (persistent, deep-seated).
  • Vertigo (labyrinthine fistula).
  • Facial Palsy (CN VII involvement).
  • Headache, Vomiting, Convulsions, Ataxia, Fever (intracranial spread).
  • Tinnitus.

Signs (On Examination):

• Tympanic Membrane Perforation:

  • Attic Perforation (in pars flaccida) or Posterior Superior Marginal Perforation (in pars tensa, involving annulus).

• Retraction Pocket: Invagination of Tympanic membrane (pars flaccida/posterior superior pars tensa). May be shallow and self-cleansing or deep with keratin accumulation.

What is Tos Classification of Pars Flaccida Retraction?

What is Sade Classification of Pars Tensa Retraction?

• Cholesteatoma: Pearly white flakes (keratin debris) visible within a retraction pocket, attic, or posterior superior margin. Congenital cholesteatoma appears as a pearl-like mass behind an intact Tympanic membrane.

• Osteitis / Granulation Tissue: Fleshy red tissue coming from the attic or posterior superior margin, indicating bone inflammation.

• Ossicular Necrosis: May be visible through the perforation.

• Cholesterol Granuloma: Bluish mass behind TM (if intact), or yellowish/brownish if ruptured/exposed.

• Tuning Fork Tests: Rinne's Negative, Weber's lateralized to the diseased ear, Absolute Bone Conduction (ABC) normal.

🔬 Investigations of Cholesteatoma

Investigations are crucial for confirming diagnosis, assessing disease extent (especially bone erosion), identifying complications, and planning surgery.

• Examination Under Microscope (EUM): Priority for all cases.

• Pure Tone Audiometry (PTA): When the ear is dry.

• Culture & Sensitivity (C&S): Of ear discharge (if active) to guide antibiotic therapy.

• Imaging:

  • X-ray Mastoid (e.g., Schuller's View)

  • CT Scan of Temporal Bone (High Resolution - HRCT): Gold standard for bony anatomy and bone erosion.

  • MRI Temporal Bone: Useful for assessing soft tissue extension and intracranial complications (e.g., brain abscess, meningitis, dural involvement). Can differentiate cholesteatoma from cholesterol granuloma or fluid. MR venography/angiography for vascular involvement.

Why is Examination under Microscope mandatory in a case of Cholesteatoma?

What is the purpose of doing Pure Tone Audiometry in Cholesteatoma?

What findings do you see in CT Temporal bone in Cholesteatoma?

🏥 Treatment of Cholesteatoma

The treatment of cholesteatoma is primarily surgical. Medical management has a very limited role.

Aim of Surgery:

1. Eradicate disease and make the ear SAFE.

2. Reconstruct the hearing mechanism.

Surgical Approaches:

• Canal Wall Down (CWD) Procedures: Remove the posterior bony EAC wall, converting the mastoid cavity and middle ear into a single, exteriorized cavity.

What are some Canal wall down procedures you know?

What are the advantages and disadvantages of Canal wall down procedures?

What is Bondy's Mastoidectomy?

• Canal Wall Up (CWU) Procedures: Remove disease while keeping the posterior bony meatal wall intact. Approach via combined access (EAC and cortical mastoidectomy).

What are some Canal wall up procedures you know?

What are the advantages and disadvantages of Canal wall up procedures?

Reconstructive Surgery:

• Hearing is typically restored by Tympanoplasty (grafting Tympanic membrane) and Ossicular Reconstruction (using prostheses, sculpted ossicles, cartilage).

• Can be performed at the time of initial surgery (single stage) or as a second-stage procedure (usually 6-12 months later) to ensure disease eradication before reconstruction.

Conservative Management in Cholesteatoma (Limited Role):

• Generally NOT the primary treatment for cholesteatoma.

• In these cases, polyps/granulation tissue may be surgically removed (cup forceps) or cauterized (silver nitrate).

What are the indications for Conservative Management in Cholesteatoma?