Pilonidal Cyst (Answer: A)
A truck driver presenting with a painful, fluctuant mass in the gluteal fold most likely has a pilonidal cyst, given the classic occupational risk factor (prolonged sitting), anatomic location (gluteal fold/intergluteal region), and clinical presentation (painful, fluctuant mass).
Clinical Reasoning
Why Pilonidal Cyst is Most Likely
Occupational correlation: Truck drivers are at increased risk due to prolonged sitting and pressure on the sacrococcygeal region, which promotes follicular occlusion and subsequent cyst formation 1
Classic location: The gluteal fold/intergluteal region is the pathognomonic location for pilonidal disease 1, 2
Characteristic presentation: A painful, fluctuant mass indicates an acute pilonidal abscess, which represents the most common symptomatic presentation of pilonidal disease 2
High prevalence in this population: Among patients with hidradenitis suppurativa (which can mimic pilonidal disease), 27% had intergluteal fold lesions, but 78% of those with available clinical diagnosis were actually pilonidal sinus disease rather than hidradenitis 1
Why Other Options Are Less Likely
Intersphincteric abscess (Option B): This would present with perianal pain, not specifically in the gluteal fold, and typically involves the anal sphincter complex with associated rectal symptoms 2
Dermoid cyst (Option C): These are congenital lesions that are typically painless, non-fluctuant, and present since birth or early childhood—not as an acute painful mass in an adult 3
Hidradenitis suppurativa (Option D): While HS can affect the gluteal region, it characteristically presents with:
- Recurrent nodules, abscesses, and draining sinus tracts (not a single fluctuant mass) 4, 5
- Multiple lesions in intertriginous areas (axillae, groin, inframammary folds) 4, 5
- Chronic progression with 2+ recurrences within 6 months or persistent lesions ≥3 months 4
- The single acute presentation described is more consistent with pilonidal disease 1
Key Diagnostic Features to Confirm
Location specificity: Pilonidal disease occurs in the midline gluteal fold/intergluteal cleft, often with visible pits or sinus openings 1, 2
Associated findings: Look for hair protruding from sinus openings, midline pits, or previous scarring from prior episodes 2
Absence of features suggesting HS: No tunnels/fistulae, no involvement of other intertriginous areas, no chronic recurrent pattern 4, 5
Common Pitfall to Avoid
The intergluteal location can lead to misdiagnosis as hidradenitis suppurativa, but the distinction is critical: pilonidal disease in this location represents 78% of intergluteal inflammatory lesions when a definitive diagnosis is made, versus only 22% being true HS 1. The single acute presentation, occupational risk factor, and midline location strongly favor pilonidal disease over the chronic, recurrent, multi-site pattern of HS 1, 4.
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