A 35-year-old man presents with a painless, firm nodule on the upper eyelid that has been present for 6 weeks. He reports no discharge, redness, or discomfort. On examination, there is a well-defined, non-tender swelling on the tarsal conjunctiva of the upper lid. The overlying skin is normal. He has a history of recurrent similar lesions on the same lid. What is the most likely diagnosis, and what is the pathophysiology?

Explanation

## Clinical Diagnosis: Chalazion ### Key Clinical Features **Key Point:** A chalazion is a chronic, painless lipogranulomatous inflammation of the meibomian gland, presenting insidiously over weeks with a firm, non-tender nodule. The patient's presentation is classic for chalazion: - **Chronic onset** (6 weeks) - **Painless, firm nodule** - **Non-tender on palpation** - **Well-defined swelling on tarsal conjunctiva** (meibomian gland location) - **Normal overlying skin** - **Recurrent history** (predisposition to lipogranulomatous response) ### Pathophysiology of Chalazion ```mermaid flowchart TD A[Meibomian gland obstruction]:::action --> B[Lipid and sebaceous material accumulation] B --> C[Chronic granulomatous inflammation] C --> D[Lipogranuloma formation] D --> E[Painless, firm nodule on tarsal conjunctiva]:::outcome E --> F{Spontaneous resolution?}:::decision F -->|Yes: 50-75% cases| G[Resolves in 4-6 months]:::outcome F -->|No| H[Intralesional steroid or surgical excision]:::action ``` **High-Yield:** Chalazion = **chronic, painless, lipogranulomatous**; Stye = **acute, painful, suppurative**. ### Differential Diagnosis Table | Feature | Chalazion | External Hordeolum | Internal Hordeolum | |---------|-----------|-------------------|-------------------| | **Onset** | Insidious (weeks) | Acute (2–3 days) | Acute (2–3 days) | | **Pain** | Painless | Painful, tender | Painful, tender | | **Location** | Tarsal conjunctiva | Lid margin (external) | Lid margin (internal) | | **Pustule** | Absent | Visible externally | Visible internally | | **Discharge** | Lipid-rich (if ruptures) | Purulent | Purulent | | **Gland** | Meibomian | Zeis/Moll | Meibomian | | **Inflammation** | Granulomatous | Suppurative | Suppurative | | **Recurrence** | Common | Less common | Less common | ### Pathophysiology Mechanism 1. **Obstruction** of meibomian gland duct 2. **Lipid accumulation** within gland acini 3. **Rupture of gland wall** → lipid extravasation into surrounding tissue 4. **Chronic granulomatous response** → macrophage and foreign-body giant cell infiltration 5. **Lipogranuloma formation** → firm, painless nodule **Clinical Pearl:** The painless nature distinguishes chalazion from acute infection. Pain suggests secondary infection, internal hordeolum, or abscess formation. ### Management Algorithm ```mermaid flowchart TD A[Chalazion diagnosed]:::outcome --> B{Size and symptoms?}:::decision B -->|Small, asymptomatic| C[Observation + warm compresses]:::action B -->|Persistent > 3 months| D[Intralesional triamcinolone injection]:::action B -->|Large, vision-threatening| E[Surgical excision via tarsal approach]:::action C --> F{Resolves?}:::decision F -->|Yes| G[Follow-up]:::outcome F -->|No| D D --> H{Response?}:::decision H -->|Yes| G H -->|No| E ``` ### Management Options 1. **Conservative** (first-line) - Warm compresses (15 min, 2–3 times daily) - Lid hygiene - Observation: 50–75% resolve spontaneously in 4–6 months 2. **Medical** (persistent cases) - Intralesional triamcinolone acetonide (40 mg/mL, 0.2–0.5 mL) - Success rate: 60–80% with single injection 3. **Surgical** (refractory or vision-threatening) - Incision and curettage via tarsal (conjunctival) approach - Allows histopathology to rule out sebaceous carcinoma (especially in recurrent cases >50 years) **Warning:** Recurrent chalazia in the same location, especially in older patients, warrant excision and histopathology to exclude sebaceous cell carcinoma. **High-Yield:** Chalazion is **self-limited in most cases** but may require intervention if persistent >3 months or vision-threatening.