Okay, let's tackle this question. The patient is a 75-year-old diabetic with severe ear pain, granulation tissue in the external auditory canal, and facial nerve involvement. Diabetic patients are prone to certain infections because of their compromised immune system. The symptoms mentioned here are classic for a specific condition.

First, I need to recall the differential diagnoses for ear infections in diabetics. External auditory canal issues can be due to various causes like otitis externa, but when there's granulation tissue and facial nerve involvement, it points to something more aggressive.

Malignant otitis externa comes to mind. That's a severe infection caused by Pseudomonas aeruginosa. Diabetic patients are particularly susceptible because of their poor blood glucose control, which impairs neutrophil function. The infection can spread to the surrounding tissues and even involve the facial nerve, leading to paralysis. The granulation tissue is a sign of chronic inflammation trying to heal the infected area.

Now, the other options might include things like furunculosis, which is a boil in the ear canal, but that usually doesn't cause granulation tissue or facial nerve issues. Cholesteatoma could be another possibility, but that's more about a skin cyst and doesn't typically present with acute pain and granulation tissue.

So the key points here are the patient's diabetes, the presence of granulation tissue, and facial nerve involvement. These all align with malignant otitis externa. The clinical pearl is that in diabetics with severe ear pain and facial nerve signs, this is a red flag condition requiring urgent treatment with appropriate antibiotics.

**Core Concept**
This question tests recognition of *malignant otitis externa*, a severe, diabetic-predisposed infection caused by *Pseudomonas aeruginosa*. Key features include granulation tissue, facial nerve palsy, and aggressive spread due to compromised host defenses in diabetes.

**Why the Correct Answer is Right**
Malignant otitis externa (MOE) occurs in immunocompromised patients, particularly diabetics, due to impaired neutrophil function. *Pseudomonas* invades the external auditory canal, leading to necrotizing otitis media. Granulation tissue forms as a reparative response, while facial nerve involvement results from direct extension of infection through the facial canal. Early diagnosis with CT/MRI and IV antibiotics (e.g., ciprofloxacin) is critical to prevent mortality.

**Why Each Wrong Option is Incorrect**
**Option A:** *Furunculosis* is a localized furuncle (boil) in the ear canal, lacking granulation tissue or facial nerve involvement.
**Option B:** *Cholesteatoma* is a keratin-retaining cyst causing bony erosion, but it does not present with acute granulation tissue or *Pseudomonas* infection.
**Option C:** *Otomycosis* (fungal infection) causes itching and white debris but spares the facial nerve and lacks aggressive granulation tissue.

**Clinical Pearl / High-Yield Fact**
**Diabetic patients with severe ear pain + facial nerve palsy = red flag for malignant otitis externa.** Remember the "Hunt’s syndrome" mnemonic (herpes zoster oticus), but differentiate from MOE by the absence of vesicles and presence of

✓ Correct Answer: A. Malignant otitis externa