A 32-year-old man comes for evaluation of a bump on the right side of his chest. He initially noticed it 4 months ago, and it has grown slightly larger in the past month. The patient has not experienced any trauma to the area or recent surgeries. He does not use tobacco or alcohol.
Skin examination is shown below. There is no drainage from the lesion or tenderness to palpation. The lesion does not change in shape when pinched at the edges. The remainder of his physical examination is within normal limits.

Which of the following is the most likely diagnosis?

Question

A 32-year-old man comes for evaluation of a bump on the right side of his chest.  He initially noticed it 4 months ago, and it has grown slightly larger in the past month.  The patient has not experienced any trauma to the area or recent surgeries.  He does not use tobacco or alcohol.
Skin examination is shown below.  There is no drainage from the lesion or tenderness to palpation.  The lesion does not change in shape when pinched at the edges.  The remainder of his physical examination is within normal limits.

Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient's lesion is consistent with an epidermal inclusion cyst (EIC, also known as epidermal cyst), which is a benign nodule containing normal epidermis that produces keratin. Although EIC often occurs when epidermis becomes lodged into the dermis due to trauma or comedones, many patients have no history of trauma or acne. EIC can occur anywhere on the body but is most common on the face, neck, scalp, and trunk. A lesion can remain stable or gradually increase in size. EICs may occasionally rupture, resulting in significant inflammation and involvement of surrounding tissue. Diagnosis is made clinically, with examination showing a dome-shaped, firm, and freely movable cyst or nodule with a central punctum (small, dilated, pore-like opening). Larger and more inflamed lesions can have a thick, yellowish-white, cheesy, and malodorous discharge. Lesions usually resolve spontaneously but can recur. Excision may be requested by patients for cosmetic reasons but is otherwise not needed. Incision and drainage are occasionally needed for infected and fluctuant cysts that are painful and erythematous. Gardner syndrome is characterized by colon cancer and numerous EICs involving the extremities. (Choice A) Acne vulgaris typically presents with comedones, which are impacted cells in the lumen of a sebaceous follicle. Open comedones (black heads) usually appear black with a wide open orifice and no central punctum. comedones (Choice B) Dermatofibroma is a benign fibroblast proliferation that typically appears as a firm, hyperpigmented nodule, most often on the lower extremities. It is nontender and has a fibrous component that may cause dimpling in the center when the area is pinched ("dimple" or "buttonhole" sign). Dermatofibroma (Choice D) Lipomas are benign, solitary, and painless subcutaneous nodules with a normal overlying epidermis. In contrast to epidermal cysts, lipomas are usually soft to rubbery and do not have a central punctum. Lipomas (Choice E) Pyogenic granuloma is a benign vascular tumor of the skin or mucus membranes that typically presents as a shiny red mass. The lesion can grow rapidly and has a friable surface that often bleeds with minor trauma. Pyogenic granuloma Educational objective: Epidermal inclusion cyst is a benign nodule containing normal epidermis that produces keratin. Patients usually develop a dome-shaped, firm, and freely movable cyst or nodule with a small central punctum. The lesion can remain stable or gradually increase in size but usually resolves spontaneously. __________ References: Epidermal inclusion cyst embedded in a recurrent benign fibrous histiocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/25284857)

A 32-Year-Old Man Comes for Evaluation of a Bump on the Right