Demystifying the Microscopic Pathology and Cellular Features of Molluscum Contagiosum

April 19, 2024

Featured image for “Demystifying the Microscopic Pathology and Cellular Features of Molluscum Contagiosum”

When patients present with raised, pearly papulesaused by the poxvirus molluscum contagiosum (MCV), recognizing its classic cytological and histological hallmarks is key.

In this article, I will explain what cytology and histopathology analyses of molluscum contagiosum can identify through my subspecialty experience. Delve further to understand the microscopic pathology behind this bothersome viral infection.

Overview of Molluscum Contagiosum

Molluscum contagiosum manifests as small, painless bumps on the skin ranging from 2 to 5 millimeters wide. The dome-shaped papules often have a characteristic central dent, giving them an “umbilicated” look. They can emerge anywhere but commonly arise on the face, underarms, lower abdomen and inner thighs.

MCV is transmitted through direct skin contact, sexual intimacy or contact with contaminated objects. Once introduced, the poxvirus infects basal skin layer cells, replicating to produce signature intracellular inclusions used in microscopic diagnosis.

Utilizing Cytology to Diagnose Molluscum

Cytology refers to microscopic examination of individual cells. For molluscum contagiosum, this involves aspirating fluid from within bumps and analyzing the extracted cells.

Sample Acquisition

Under local anesthesia, use a small needle syringe to pierce lesion skin and draw up cells from the central molluscum cavity. Transfer this aspirated fluid onto glass slides.

Alternatively, firmly smear the bump across slides to transfer cells for staining.

Staining and Microscopy

Apply specialized stains like Giemsa, Papanicolaou or hematoxylin-eosin to color molluscum cells. This enhances visibility of microscopic structural details under high magnification.

Scan stained slides under a cytopathology microscope, examining patterns in extracted lesion cells. The presence of certain uniquely defining inclusion bodies allows confirming molluscum infection.

Identification of Molluscum Bodies

Infected keratinocytes will showcase purple-stained, round cytoplasmic vacuoles packed with MCV particles. These molluscum bodies represent proliferated virions pushing the cell nucleus aside. Finding such masses proves discerning molluscum infection on cytology.

Exploring Histopathology of Molluscum

Histopathology uses surgical excision followed by tissue sectioning and microscopy. This analysis of overall lesion architecture again reveals signature changes in molluscum:

Sample Excision

Under local anesthetic, use a scalpel or curette instrument to fully scrape away a molluscum growth down to subcutaneous fat. Place tissue sections into preservative solutions.

Sectioning and Staining

Process fixed molluscum biopsy samples using reagents that solidify and embed tissues into paraffin blocks. Use a microtome to slice tissue paper-thin and mount sections onto pathology slides.

Finally, apply special histological stains like hematoxylin and eosin for imaging under high power microscopy.

Microscopic Architecture Changes

Molluscum lesions showcase enlarged, swollen epidermal cells whose cytoplasm gets replaced by vacuoles filled with molluscum virions (microscopic poxvirus particles). These cytoplasmic viral inclusions compress the host nucleus, serving as classic histological signs of infection.

Surrounding uninfected cells exhibit characteristic beanshaped cavities from virions invading deeper skin layers too. Together, these microscopic observations prove molluscum contagiosum infection on histopathology specimen review.

How Microscopy Guides Molluscum Treatment

Confirming MCV infection via cytology or histopathology allows prompt treatment initiation to curb transmission and hasten recovery. Common medical procedures after diagnosis include:

  • Cryosurgery: Freezing lesions with liquid nitrogen
  • Curettage: Scraping away growths surgically
  • Laser Therapy: Using focused light beams to destroy bumps
  • Medicated Ointments: Prescription creams to dry out bumps

So accurately identifying those problematic bumps as infectious molluscum under the microscope is the vital first step toward targeted treatment.

FAQs on Molluscum Pathology

What stains help identify molluscum under a microscope?

Specialized hematoxylin-eosin (H&E) stain is the preferred technique to highlight molluscum pathology for histology. Giemsa or Pap stains also help accentuate cytoplasmic viral inclusions on cytology.

What is the cytological morphology of molluscum?

Infected cells showcase enlarged cytoplasm packed with deeply basophilic spherical bodies representing clusters of MCV virions. These push the peripheral nucleus aside, serving as cytology proof of infection.

Does molluscum always require biopsy for diagnosis?

While 100% diagnostic, biopsies and histopathology analysis is often unnecessary if clinical manifestations are classical. In atypical cases, sampling cells inside bumps via fine needle aspiration for cytology can quickly confirm molluscum minus excisional surgery.

What other skin conditions can microscopically mimic molluscum?

Analyses sometimes confuse molluscum with conditions like wart virus infections, seborrheic keratosis or even metastatic cancer deposits. This makes experienced sub-specialty pathologist review critical for correctly distinguishing molluscum microscopic findings.

Why diagnose molluscum contagiosum under a microscope at all?

Confirming poxvirus infection via presence of unique cytological and histological features allows for precisely targeted treatment plans instead of guessing therapy based on visual examination alone.

Conclusion – Key Microscopic Takeaways

  • Molluscum contagiosum shows intracellular vacuoles packed with virions
  • Cytology examines lesion cell aspirates under a microscope
  • Histopathology studies excised tissue architecture changes
  • Signature microscopic findings differentiate lesions from warts
  • Microscopy guides accurate virus-specific treatment regimens

So if molluscum-like bumps are proving diagnostically difficult clinically, having a dermatopathologist microscope specialist review cell or tissue architecture can conclusively diagnose infection. This then paves the way for specific antiviral treatment to kick those frustrating bumps once and for all!

Rate this post

Related articles


Cold Plasma System

The world's first handheld cold plasma device

Learn More

Made in USA