What is a Dilated Pore of Winer?

Patient Presentation
A 22-year-old female came to clinic with a lesion along her hairline near her ear. She said that it has been there “for a long time.” It hadn’t changed much in size but is always there. When she manipulates it, “This hard thing like a grain of rice comes out and then some other white stuff. It seems to get smaller then but then comes back and there is a black spot like acne.” She denies any pain or swelling unless she has just manipulated it. “It’s small now but I don’t want it to grow larger and its not getting better,” she related to the pediatrician. She had a history of mild to moderate comedomal acnes that was controlled with retinoids and benzoyl peroxide.

The pertinent physical exam showed a healthy female with normal vital signs. She had some mild comedomal acne on her nose and cheeks and a few lesions on her forehead and upper back. None were near this lesion. Near her right ear and slightly above was a 3 mm round, slightly papular lesion with a central pore that appeared to be filled with keratin material that was darkened and somewhat hardened. Light manipulation did not express any material. It was not vesicular. There was no surrounding erythema.

The pediatrician explained to the patient and medical student who was present that she thought this could be several things, “It could be an acne lesion but that doesn’t seem right as it is harder and less like a blister, and doesn’t change locations. It could be an inclusion cyst but those are usually rounder under the skin and this isn’t. Also given the location it could be an ear pit but that usually would have been noticed when you were younger and this seems too high up from the ear for that. I also remember there is something with a special name that is benign but has a big, dilated pore which this looks like. I can’t remember that name since we don’t see them much in kids.” After discussion with the patient she was referred to a dermatologist as the patient wanted to have the lesion excised, and the dermatologist confirmed the diagnosis of a dilated pore of Winer.

Dilated pore of Winer (DPW) was first described by Louis H. Winer in 1954 in his article entitled “The Dilated Pore, A Trichepithelioma.”

It is a benign follicular tumor with particular histopathological characteristics. Its’ differential diagnosis includes:

  • Comedomal acne
  • Pilar sheath acanthoma – seen as a solitary papule with keratin plug on the central area of face
  • Nevus comedomes – multiple dark comedomes with central dilated dark openings
  • Epidermal inclusion cysts – more nodular with or without keratin plug where the keratin material has a foul odor
  • Tricofolliculoma
  • Basal cell carcinoma – occasionally seen on biopsy

Learning Point
DP presents as a single, enlarged pore which can be relatively small to several millimeters across. The pore is often occluded with a keratin plug that if expressed has white, soft creamy, keratin material behind it. The end of the keratin plug can be quite dark and the plug can be quite hard because of inspissation. It can also present as a papule with a follicular pore. They generally occur on the face, head and neck, but can also occur on the trunk. They are more common in males than females and in middle-older aged adults. However they can occur in older adolescents and young adults.

DPs are asymptomatic (but can be irritated by manipulation) and usually have been present for a long time before consulting a physician. The history may include that the keratin plug and material has been expressed only to refill over the next few weeks.

Diagnosis is usually clinical with biopsy for treatment or if needed for another reason. No specific treatment is required but excision may be completed for cosmetic or functional concerns.

Questions for Further Discussion
1. How do you treat acne?
2. What are indications for excision of a dermatological lesion?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Skin Conditions

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Winer LH. The Dilated Pore, A Trichoepithelioma. Journal of Investigative Dermatology. 1954;23(3):181-188. doi:10.1038/jid.1954.97

Tellechea O, Cardoso JC, Reis JP, et al. Benign follicular tumors. An Bras Dermatol. 2015;90(6):780-798. doi:10.1590/abd1806-4841.20154114

Bishnoi A, Aggarwal D, Vinay K, Radotra BD. Visual Dermatology: Dilated Pore of Winer. J Cutan Med Surg. 2019;23(3):332-332. doi:10.1177/1203475419825770

Benedetto CJ, Riley CA, Athalye L. Dilated Pore Of Winer. In: StatPearls. StatPearls Publishing; 2022. Accessed August 5, 2022. http://www.ncbi.nlm.nih.gov/books/NBK532967/

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa