Skin nontumor
Infectious disorders
Molluscum contagiosum


Topic Completed: 20 July 2020

Minor changes: 20 July 2020

Copyright: 2002-2020, PathologyOutlines.com, Inc.

PubMed Search: Molluscum contagiosum[title] “loattrfree full text”[sb] pathology

Osward Y. Carrasquillo, M.D., M.P.H.
Jorge L. Sánchez, M.D.
Page views in 2019: 16,418
Page views in 2020 to date: 12,706
Cite this page: Carrasquillo OY, Sánchez JL. Molluscum contagiosum. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumormolluscum.html. Accessed October 29th, 2020.
Definition / general
Essential features
  • Infectious dermatosis most commonly affecting children and immunocompromised patients
  • Majority of infections are caused by MCV1 (98% of cases)
  • In contrast to most double stranded DNA viruses, poxvirus replicates in the cytoplasm
  • Henderson-Paterson bodies, also known as molluscum bodies, are large (up to 35 microns) intracytoplasmic eosinophilic inclusion on keratinocytes
ICD coding
  • ICD-10: B08.1 - Molluscum contagiosum
Epidemiology
Sites
Pathophysiology
Etiology
Clinical features
Diagnosis
Prognostic factors
Case reports
Treatment
  • Self limited
  • Mechanical methods: cryotherapy, curettage, pulse dye laser
  • Chemical methods: potassium hydroxide, podophyllotoxin, trichloroacetic acid, salicylic acid, lactic acid, glycolic acid, benzoyl peroxide and tretinoin
  • Immunomodulatory methods: imiquimod, oral cimetidine, interferon alfa, candidin and diphencyprone
  • Antivirals: cidofovir (Clin Cosmet Investig Dermatol 2019;12:373)
Clinical images

Contributed by Marely Santiago-Vazquez, M.D.

Dermoscopy features

Molluscum contagiosum morphology

Clustered papules

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Jorge L. Sánchez, M.D.

Epidermal hyperplasia

Henderson-Patterson bodies

Eosinophilic inclusion bodies

Inflammatory infiltrate

Large intracytoplasmic inclusions

Virtual slides

Images hosted on other servers:

Molluscum contagiosum

Videos

Molluscum versus myrmecia wart - dermpath lookalikes

Sample pathology report
  • Left superior eyelid skin, biopsy:
    • Molluscum contagiosum (see comment)
    • Comment: There is epidermal hyperplasia with large eosinophilic cytoplasmic bodies within keratinocytes.
Differential diagnosis
  • Common wart:
    • Verrucous or filliform flesh colored papules
  • Herpes simplex:
    • Grouped vesicles that rupture quickly, leading to painful ulcerations with scalloped borders
    • Nuclear viral inclusions (multinucleation, nuclear molding, margination of chromatin)
  • Juvenile xanthogranuloma:
    • Dome shaped, yellowish orange papules or nodules
    • Triple association between juvenile xanthogranuloma, neurofibromatosis type 1 and juvenile promyelomonocytic leukemia has been reported
    • Touton giant cells, histiocytes, lymphocytes and eosinophils in reticular and papillary dermis
  • Spitz nevi:
    • Lesions typically located in face and extremities
    • Melanocytic nests with epithelioid cells at the dermal-epidermal junction
    • Kamino bodies within the epidermis
  • Basal cell carcinoma:
    • Most common in chronically sun exposed areas
    • Nest of basaloid cells with peripheral palisading and retraction artifact
Board review style question #1

A 6 year old boy presents with multiple scattered, flesh colored, small skin papules on the trunk and upper extremities. His medical history was unremarkable and his older sister had similar lesions in the past. A skin biopsy of one of the lesions is shown. Which of the following is the most likely cause of his condition?

  1. Human papillomavirus type 1 (HPV1)
  2. Human papillomavirus type 2 (HPV2)
  3. Human papillomavirus type 3 (HPV3)
  4. Molluscum contagiosum virus type 1 (MCV1)
  5. Molluscum contagiosum virus type 2 (MCV2)
Board review answer #1
D. Molluscum contagiosum virus type 1 (MCV1). The histology shows molluscum contagiosum, which is caused by the molluscum contagiosum virus (MCV) of the Poxviridae family (double stranded DNA). There are several types of MCV but the most common by far is MCV1 (98% of cases). MCV1 most commonly affects children, whereas MCV2 is usually seen in patients with HIV. Although verruca vulgaris from HPV (especially type 1) is common in children, the specimen is characteristic for molluscum contagiosum as it shows epidermal hyperplasia with large eosinophilic inclusion bodies on the keratinocytes (Henderson-Patterson bodies).

Reference: Molluscum contagiosum

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Board review style question #2
A patient is diagnosed with molluscum contagiosum after a skin biopsy was performed by his dermatologist. Which of the following type of viruses is responsible for causing his lesions?

  1. Double stranded DNA virus replicating in the cytoplasm
  2. Double stranded RNA virus replicating in the nucleus
  3. Single stranded DNA virus replicating in the cytoplasm
  4. Single stranded DNA virus replicating in the nucleus
  5. Single stranded RNA virus replicating in the cytoplasm
Board review answer #2
A. Double stranded DNA virus replicating in the cytoplasm. Molluscum contagiosum is part of the Poxviridae family. The poxvirus replication is unusual as it is a double stranded DNA virus replicating in the cytoplasm instead of the nucleus.

Reference: Molluscum contagiosum

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