Subtitle: Exam-focused comparison of molluscum contagiosum vs myrmecia wart histopathology with diagnostic clues, tables, slide images, virtual slides and MCQs for pathology exams.

Author: PathologyMCQ Content Team
Category: Dermatopathology
Last Updated: Jan 2026
Read Time: ~10 mins

At-a-Glance Summary

Feature	Molluscum Contagiosum	Myrmecia Wart
Causative Virus	Poxvirus	HPV (type 1 common)
Usual Location	Non-acral skin (trunk, genital, limbs)	Palms & soles
Epidermal Architecture	Crateriform epidermal invagination	Papillomatous “ant-hill” pattern
Inclusion Bodies	Uniform Henderson–Patterson bodies	Variable eosinophilic inclusions
Diagnostic Hallmark	Uniform inclusions + crater	Papillomatosis + variable inclusions

Table of Contents

1. What is Molluscum Contagiosum?

Molluscum contagiosum is a viral cutaneous infection caused by a poxvirus that produces characteristic intracytoplasmic inclusion bodies within a crateriform epidermal lesion.

Key Points

• Virus: Molluscum contagiosum virus (Poxviridae).
• Pathogenesis: Viral replication in keratinocytes leads to cytoplasmic inclusion formation.
• Transmission: Skin contact, autoinoculation.

2. What is Myrmecia Wart?

Myrmecia wart is a verrucous lesion of the palms and soles caused by HPV (often type 1) characterized by papillomatous epidermal changes and variable inclusions.

Key Points

• Virus: Human papillomavirus (HPV), type 1 common.
• Location specificity: Palms and soles almost exclusively.
• Clinical significance: Often painful due to plantar pressure.

3. How Does Molluscum Present Clinically?

Molluscum contagiosum presents as multiple umbilicated pearly papules on non-acral skin.

1. The central umbilication seen clinically corresponds to the underlying epidermal crater histologically.
2. Papules are typically small, firm, smooth, and pearly.
3. Lesions commonly occur on lower abdomen, thighs, and genital areas.

4. How Does Myrmecia Wart Present Clinically?

Myrmecia wart presents as rough, warty lesions on the soles or palms, often painful with pressure.

1. Plantar location frequently leads to discomfort with ambulation.
2. The wart’s rough surface reflects HPV-induced hyperkeratosis.
3. Lesions lack the central umbilication seen in molluscum.

5. How is Molluscum Contagiosum Diagnosed Histologically?

Crateriform Epidermal Architecture

Molluscum histology shows a crateriform (cup-shaped) invagination of epidermis filled with virally infected cells.

1. The epidermis forms a broad crater that corresponds to the clinical central depression.
2. Viral proliferation fills the invagination.
3. The crater differentiates molluscum from papillomatous lesions.

Uniform Henderson–Patterson Bodies

Molluscum contagiosum histology is defined by uniform, eosinophilic intracytoplasmic inclusion bodies called Henderson–Patterson bodies.

1. These bodies are viral aggregates within keratinocytes.
2. They are uniform in size and shape, a key diagnostic clue.
3. Nuclei are displaced toward the periphery of infected cells.

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6. How is Myrmecia Wart Diagnosed Histologically?

Papillomatous / “Ant-Hill” Epidermal Architecture

Myrmecia wart histology shows papillomatous epidermal proliferation with irregular downward growth (“ant-hill” pattern).

1. The surface shows papillomatosis rather than a smooth crater.
2. Epidermal ridges extend irregularly, reflecting HPV-driven hyperplasia.
3. Depth and pattern differ from molluscum’s crateriform change.

Variable Eosinophilic Inclusions

Myrmecia wart exhibits eosinophilic granular inclusions of varying sizes within keratinocytes.

1. These inclusions are due to HPV cytopathic effects.
2. They are heterogeneous in size and shape, unlike molluscum bodies.
3. Variability is a key distinguishing feature.

7. What Are the Key Histologic Mimics and How Do You Distinguish Them?

Key histologic mimics of molluscum and myrmecia warts include verruca vulgaris variants and HPV warts; they are distinguished by architectural patterns and inclusion features.

List of Mimics

• Verruca vulgaris: Papillomatous warts with koilocytosis; no crateriform invagination.
• Flat warts: Superficial flattening and koilocytosis; lacks uniform Henderson–Patterson bodies.
• Condyloma acuminatum: Papillomatous and acanthotic with classic HPV changes.

Distinguishing Points

1. Architecture: Crateriform vs papillomatous guides diagnosis.
2. Inclusions: Uniform vs variable.
3. Location: Acral vs non-acral helps separate myrmecia from molluscum.

8. Molluscum Contagiosum vs Myrmecia Wart Histopathology: Architectural Features and Inclusion Body Patterns

Direct Answer: Molluscum and myrmecia show distinct epidermal architecture and inclusion body characteristics.

Feature	Molluscum Contagiosum	Myrmecia Wart
Epidermal Architecture	Crateriform	Papillomatous (“ant-hill”)
Inclusion Bodies	Uniform Henderson–Patterson	Variable eosinophilic
Clinical Site	Non-acral	Palmar/plantar
Diagnostic Clue	Crater + uniform bodies	Papilloma + variable bodies

9. Clinical-Pathologic Correlation: How Site and Symptoms Guide Diagnosis

Clinical site and symptom patterns provide critical clues that correlate with histology.

Key Correlations

1. Palmar/plantar pain: Suggests myrmecia wart architecture.
2. Non-acral umbilicated papules: Characteristic of molluscum.
3. Uniform inclusions on biopsy: Aligns with poxvirus pathology.

10. Diagnostic Clues Table

Clue	Molluscum Contagiosum	Myrmecia Wart
Pain on pressure	Rare	Often present
Inclusion uniformity	Yes	No
Epidermal shape	Crateriform	Papillomatous
Typical viral agent	Poxvirus	HPV

11. High – yield MCQS

12. Exam Pearl

Uniform eosinophilic bodies within a crateriform epidermis = molluscum contagiosum histopathology.

13. Key Takeaway

Palmar/plantar warty lesion with papillomatous ant-hill architecture and variable inclusions = myrmecia wart histology.

14. Recommended learning

Video summary