Case 1: Reactive hyperplastic epidermis with keratosis is seen on the superficial surface of the ear.
Necrotic cartilage (amorphous pink material) with dystrophic calcification (dark purple areas) is present deep to the epidermis. Unfortunately, this particular biopsy was received in fragments and we could not demonstrate the lesion in its entirety.
Case 2: The epithelium (bottom image) is ulcerated with underlying fibrinoid necrosis and degenerating cartilage (top image).
A closer view at the degenerating cartilage.
The ulcer bed exhibits fibrinoid necrosis and inflammation.
Key histologic features include hyperplasic and ulcerated epidermis and degeneration of subjacent cartilage. Granulation tissue, solar elastosis and a mixed inflammatory infiltrate will also be present between the epidermis and underlying cartilage (Rapini).
The lesion presents as a solitary painful nodule on the helix or less commonly, the antihelix of the ear. It usually affects middle-age or older men, but 10-35% of cases can arise in women (Marks). The lesion may be precipicated by trauma, cold injury, actinic damage or pressure --i.e. the patient often admits to sleeping on the affected ear (Marks).
On clinical exam, the nodule is firm and tender with a rolled edge and may be ulcerated or crusted.
Marks VJ, Akin RS. Chondrodermatitis nodularis helicis: eMedicine. Last updated Jan 15, 2010. Available at: emedicine.medscape.com/article/1119141-overview
Rapini RP. Practical Dermatopathology. Philadelphia, PA: Elsevier; 2005: 229-230.