Image Letter

An Incidental Finding of Pili-Multi Gemini of the Back

Author Affiliation(s)

Case Presentation

A 57-year-old man presented with a blue, pigmented patch across the left upper back. This was clinically consistent with nevus of Ito ( Figure 1A ). On closer inspection with dermoscopy short, dark, tufted hairs were identified which were widespread across the entire back. Multiple hairs measuring < 1 mm arose from each follicular opening ( Figure 1B ). This finding was isolated to the back. There was no history of prior hair removal to otherwise explain this appearance. A clinical diagnosis of widespread pili multigemini was made.

Figure 1 .

(A) 15 cm blue pigmented patch distributed across the left upper back with visible widespread dark, follicular changes. (B) Dermoscopy demonstrating multiple 0.5mm–1mm tufted hairs arising from within each follicular opening.

Skin punch biopsy was performed which confirmed the clinical diagnosis. Treatment was not indicated as the patient was asymptomatic at time of diagnosis.

Teaching Point

Pili multigemini is an unusual hair follicle dysplasia, characterized by clusters of shafts that emerge from a single follicle. Folliculitis may also be present. Diagnosis is clinical. Dermoscopy or trichoscopy is helpful for visualizing multiple hairs emerging from the same follicular opening. Electron microscopy shows multiple distorted hair shafts within a common root sheath. Treatment with permanent, laser ablative techniques can be considered for cosmesis. It is rarely described in the literature due to under-reporting in clinical practice and is most commonly found in male facial hair [ 1 , 2 ] .

Dermatologists should be vigilant for pathology that may be hidden within concomitant skin changes and this case emphasizes the importance of thorough full skin examination enhanced by the use of dermoscopy. It raises the discussion of whether pili multigemini represents a true, rare phenomenon or underdiagnosis due to its asymptomatic nature.


  1. Extensive pili multigemini over the back Ciudad-Blanco C, Heffernan J, Montero E, et al. Int J Trichology.2014;6(4):180-181. CrossRef PubMed
  2. The prevalence of pili multigemini Lester L, Venditti C. Br J Dermatol.2007;156(6):1362-1362. CrossRef PubMed

Send mail to Author

Send Cancel