Pilar sheath acanthoma

From Libre Pathology
Jump to navigation Jump to search
Pilar sheath acanthoma
Diagnosis in short

Possibly a pilar sheath acanthoma. H&E stain.

LM cystic cavity with branching - contains keratineous material, usually extends from surface to deep cutis, cyst lining consists of a thickened squamous epithelium
LM DDx trichofolliculoma, dilated pore of Winer, epidermal inclusion cyst
Gross raised lesion, central cavitation
Site skin - classically upper lip

Clinical history typically middle aged - 50s
Prevalence rare
Prognosis benign

Pilar sheath acanthoma is a rare benign skin lesion.


  • Rare.[1]
  • Considered a hamartoma.[1]
  • Does not regress like keratoacanthoma.
  • Typically middle aged individuals - median age in one series 55 years old, range 46-75 years old.[2]


  • Raised lesion with a central depression - somewhat similar to keratoacanthoma.
  • Classcially upper lip.[2]




  • Cystic cavity with branching:[3]
    • Contains keratineous material.
    • Usually extends from surface to deep cutis - like a hair shaft.
    • Cyst lining consists of a thickened squamous epithelium (acanthosis).
  • +/-Mitoses.




See also


  1. 1.0 1.1 Vakilzadeh, F. (Jan 1987). "[Pilar sheath acanthoma].". Hautarzt 38 (1): 40-2. PMID 3557980.
  2. 2.0 2.1 2.2 Mehregan, AH.; Brownstein, MH. (Oct 1978). "Pilar sheath acanthoma.". Arch Dermatol 114 (10): 1495-7. PMID 718186.
  3. 3.0 3.1 3.2 3.3 Choi, YS.; Park, SH.; Bang, D. (Dec 1989). "Pilar sheath acanthoma--report of a case with review of the literature.". Yonsei Med J 30 (4): 392-5. PMID 2697113.
  4. Bavikar, RR.; Gaopande, V.; Deshmukh, SD. (Jan 2011). "Postauricular pilar sheath acanthoma.". Int J Trichology 3 (1): 39-40. doi:10.4103/0974-7753.82136. PMID 21769237.