Skin nontumor
Infectious disorders
Virus associated trichodysplasia spinulosa
Last author update: 1 April 2011
Last staff update: 21 August 2020
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PubMed Search: Virus associated trichodysplasia spinulosa
Table of Contents
Definition / general | Clinical features | Microscopic (histologic) description | Electron microscopy description | Differential diagnosisCite this page: Hamodat M. Virus associated trichodysplasia spinulosa. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorVATS.html. Accessed March 21st, 2023.
Definition / general
- Very rare (< 10 cases reported) cutaneous eruption of spiny papules due to polyoma virus infection
Clinical features
- Usually affects face and ear, less often trunk and extremities; may cause alopecia
- Associated with kidney transplant, acute lymphocytic leukemia
- Similar to cyclosporine-induced follicular dystrophy and pilomatrix dysplasia
Microscopic (histologic) description
- Abnormally maturing anagen hair follicles (no papillae, ectatic infundibula) with excessive inner root sheath differentiation, and hyperkeratotic infundibula (Am J Surg Pathol 2005;29:241)
- Hair follicles are dilated and contained hyperkeratotic and parakeratotic debris in place of hair shafts
- Hyperplastic areas of differentiation into hair matrix with cellular disorganization and loss of nuclear polarity
Electron microscopy description
- Intranuclear polyoma type virus particles
Differential diagnosis
- Keratosis pilaris: usually arms and legs, small ecstatic infundibula with keratin plugs
- Lichen spinulosis: children and adolescents, extensor arms, lateral thighs, neck and buttock, minute filiform horny spines grossly due to follicular infundibular hyperkeratosis
- Drug induced folliculitis
