A flesh-colored, dome-shaped, 1.2-cm nodule has appeared on .the right ear lobe of a 60-year- old man in the past month. A central keratin-filled crater is surrounded by proliferating squamous epithelium. This lesion regresses over/ the next month and then disappears. Which of the following diagnoses is most appropriate for this lesion?
A flesh-colored, dome-shaped, 1.2-cm nodule has appeared on .the right ear lobe of a 60-year- old man in the past month. A central keratin-filled crater is surrounded by proliferating squamous epithelium. This lesion regresses over/ the next month and then disappears. Which of the following diagnoses is most appropriate for this lesion?
💡 Explanation
**Core Concept**
Seborrheic keratosis is a benign skin growth that typically appears in older adults, characterized by a flesh-colored, dome-shaped nodule with a central keratin-filled crater, often surrounded by proliferating squamous epithelium.
**Why the Correct Answer is Right**
This lesion regresses and disappears within a short period, which is a characteristic feature of seborrheic keratosis. The presence of a central keratin-filled crater and proliferating squamous epithelium is also consistent with this diagnosis. Seborrheic keratoses are often associated with solar exposure and can appear on sun-exposed areas, such as the earlobe.
**Why Each Wrong Option is Incorrect**
**Option A:** Basal cell carcinoma is a malignant skin tumor that typically presents as a firm, shiny nodule with telangiectatic vessels, not a flesh-colored, dome-shaped nodule with a central keratin-filled crater.
**Option B:** Actinic keratosis is a precancerous lesion that typically appears as a small, rough, scaly patch or nodule in sun-exposed areas, but it does not regress and disappear within a short period.
**Option C:** Squamous cell carcinoma is a malignant skin tumor that typically presents as a firm, ulcerated nodule with rolled borders, not a flesh-colored, dome-shaped nodule with a central keratin-filled crater.
**Option D:** Melanoma is a malignant skin tumor that typically presents as a pigmented, irregularly-shaped nodule or patch, not a flesh-colored, dome-shaped nodule with a central keratin-filled crater.
**Clinical Pearl / High-Yield Fact**
Seborrheic keratoses are often referred to as "senile warts" or "age spots," and they are a common skin finding in older adults.