Question 111: A 50-year-old man comes to the physician for a routine checkup. He has had a progressively increasing swelling on the nape of his neck for 2 months. He does not have a fever or any discharge from the swelling. He underwent a colectomy for colon cancer at the age of 43 years. He has type 2 diabetes mellitus, hypertension, and osteoarthritis of the left knee. Current medications include insulin glargine, metformin, enalapril, and naproxen. He has worked as a traffic warden for the past 6 years and frequently plays golf. He appears healthy. His temperature is 37.3°C (99.1°F), pulse is 88/min, and blood pressure is 130/86 mm Hg. Examination of the neck shows a 2.5-cm (1-in) firm, mobile, and painless nodule. The skin over the nodule cannot be pinched. The lungs are clear to auscultation. The remainder of the examination shows no abnormalities. A photograph of the lesion is shown. Which of the following is the most likely diagnosis?
- A. Dermatofibroma
- B. Actinic keratosis
- C. Squamous cell carcinoma
- D. Lipoma
- E. Epidermoid cyst (Correct Answer)
Explanation: ***Epidermoid cyst***
- The **inability to pinch the skin over the nodule** is the key diagnostic feature (positive Fothergill sign), indicating the lesion is attached to the overlying skin—characteristic of an **epidermoid cyst**
- Epidermoid cysts present as **firm, mobile, painless nodules** that grow slowly over weeks to months
- The **nape of the neck** is a common location for these benign cysts originating from the epidermal layer
- Absence of fever, discharge, or inflammation indicates an uninfected, benign lesion
*Dermatofibroma*
- Typically presents as a small, **reddish-brown papule** that demonstrates a **"dimple sign"** when the skin is pinched (opposite of this patient's finding)
- Usually smaller than the described 2.5-cm nodule
- The positive Fothergill sign (cannot pinch skin) excludes this diagnosis
*Actinic keratosis*
- Presents as a **rough, scaly patch** with sandpaper-like texture on sun-exposed skin, not a smooth nodule
- Precancerous lesion that does not present as a firm, mobile subcutaneous mass
- Would not produce the inability to pinch skin over the lesion
*Squamous cell carcinoma*
- Usually presents as a **firm nodule with ulceration, crusting, or central depression** that grows more rapidly
- Often fixed or indurated rather than mobile
- The benign clinical features (mobile, painless, no ulceration, slow growth) make this unlikely
*Lipoma*
- Benign tumor of fatty tissue that is characteristically **soft and rubbery**, not firm
- Typically shows **easily mobile skin over the lesion** (negative Fothergill sign)
- The firm consistency and inability to pinch skin exclude this diagnosis
Question 112: A 62-year-old woman comes to the physician because of increasing blurring of vision in both eyes. She says that the blurring has made it difficult to read, although she has noticed that she can read a little better if she holds the book below or above eye level. She also requires a bright light to look at objects. She reports that her symptoms began 8 years ago and have gradually gotten worse over time. She has hypertension and type 2 diabetes mellitus. Current medications include glyburide and lisinopril. When looking at an Amsler grid, she says that the lines in the center appear wavy and bent. An image of her retina, as viewed through fundoscopy is shown. Which of the following is the most likely diagnosis?
- A. Age-related macular degeneration (Correct Answer)
- B. Diabetic retinopathy
- C. Cystoid macular edema
- D. Central serous retinopathy
- E. Hypertensive retinopathy
Explanation: ***Age-related macular degeneration***
- The patient's age (62 years), progressive **blurring of central vision**, difficulty reading, need for bright light, and **wavy lines on Amsler grid** are classic symptoms of age-related macular degeneration (AMD).
- AMD primarily affects the **macula**, reducing central vision while sparing peripheral vision. The fundoscopy image would likely show drusen or signs of neovascularization consistent with AMD.
*Diabetic retinopathy*
- While the patient has type 2 diabetes, **diabetic retinopathy** typically presents with **microaneurysms**, hemorrhages, cotton wool spots, and neovascularization on fundoscopy.
- The symptom of wavy lines on an Amsler grid specifically points to macular involvement, which, in the context of diabetes, would be **diabetic macular edema**, but the overall presentation is more consistent with AMD.
*Cystoid macular edema*
- **Cystoid macular edema** involves fluid accumulation in the fovea, leading to central vision loss and distorted vision, which might also cause wavy lines on an Amsler grid.
- However, it's often a complication of other conditions like **diabetic retinopathy**, retinal vein occlusion, or inflammation, and while possible, AMD is a more direct and common explanation for this constellation of symptoms in an older adult.
*Central serous retinopathy*
- **Central serous retinopathy** typically affects younger to middle-aged adults, often associated with stress and corticosteroid use.
- While it can cause **blurry vision** and metamorphopsia (wavy lines), the patient's age and the chronic, progressive nature of her symptoms make AMD a more probable diagnosis.
*Hypertensive retinopathy*
- Although the patient has hypertension, **hypertensive retinopathy** manifests with **arteriolar narrowing**, AV nicking, hemorrhages, and exudates on fundoscopy.
- It does not typically cause the specific symptom of wavy lines on an Amsler grid as a primary complaint, nor does it typically present with such a long, progressive course of central vision loss.
