Charles Herndon

Verruca vulgaris: Papillomatosis + toeing-in + tiers of parakeratosis.
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Myrmecia: Eosinophilic inclusions + large keratohyalin granules.
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Epidermodysplasia verruciformis2: Blue-gray cytoplasm + dysplasia.
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✅ Verruca vulgaris
-Exophytic papillomatosis with hyperkeratosis
-Tiers of parakeratosis over dermal papillae
-Koilocytes and clumped keratohyalin granules
-Inward curving (toeing-in) of rete ridges
-HPV-1, HPV-2, and HPV-4

❌ Epidermodysplasia verruciformis
-Widespread flat wart-like lesions
-Blue-gray pallor of upper keratinocytes
-Dysplastic changes/nuclear atypia
-Associated with HPV 5 and 8

❌ Myrmecia
-Deep endophytic growth pattern
-Abundant eosinophilic cytoplasmic inclusions
-Large coarse keratohyalin granules
-Associated with HPV 1

2nd chance! Lower power.
What is the diagnosis?
A. Verruca vulgaris
B. Myrmecia
C. Epidermodysplasia verruciformis (EDV)

#TooCloseToDiagnose? 🧐
A. Verruca vulgaris
B. Myrmecia
C. Epidermodysplasia verruciformis
#Pathology #DermPath

✅ Pleomorphic Adenoma 🎯
• Biphasic, ductal/epithelial cells and myoepithelial cells (plasmacytoid or spindled)
• Metachromatic chondromyxoid/fibrillary matrix with tumor cells embedded in stroma
• Bland cytology with smooth nuclear contours; background may show stromal fragments and bare nuclei

❌ Acinic Cell Carcinoma
• Acinar-type cells in cohesive sheets or loose clusters without chondromyxoid matrix
• Abundant granular to vacuolated cytoplasm with zymogen granules; may show clear-cell change
• Round uniform nuclei with variable nucleoli; naked nuclei may be present

❌ Adenoid Cystic Carcinoma
• Uniform small basaloid cells with scant cytoplasm, often with many naked nuclei
• Hyaline basement-membrane-like globules or cylinders with cells wrapping around them
• Cribriform/tubular clusters with pseudocystic spaces

❌ Warthin Tumor
• Oncocytic epithelial sheets with dense granular cytoplasm and distinct cell borders
• Abundant lymphoid background with lymphoglandular bodies
• Cystic debris with macrophages and granular proteinaceous material

2nd Look

🔬 #CytoQuiz 🤤 #Parotid 🤤
A) Warthin Tumor
B) Pleomorphic Adenoma
C) Acinic Cell Carcinoma
D) Adenoid Cystic Carcinoma
🙏 🖼️ @CytoAtlas #CytoPath

✅ Granulomatous Inflammation 🎯
• Tightly cohesive aggregates of epithelioid histiocytes
• Syncytial appearance with indistinct cell borders
• Nuclei are pale, oval to elongated, often boomerang or slipper-shaped
• Diagnosis of exclusion requires negative stains for organisms

❌ Pulmonary Hamartoma
• Biphasic mixture of epithelial and mesenchymal elements
• Fibromyxoid stroma (magenta on Diff-Quik)
• Benign respiratory epithelium and cartilage
• Bland spindled cells within stroma

❌ Adenocarcinoma
• Glandular differentiation with acini or papillae
• Enlarged nuclei with prominent nucleoli
• Vacuolated or delicate, wispy cytoplasm
• Intracytoplasmic mucin may be present

❌Squamous Cell Carcinoma
Dense, 'hard' cytoplasm with distinct cell borders
Keratinization (Orangeophilia on Pap, deep blue on Diff-Quik)
Pleomorphic shapes: Tadpole, spindle, or caudate cells
Hyperchromatic, angular, 'ink-dot' nuclei (pyknosis)
Background often contains necrotic debris

❌ Small Cell Carcinoma
• High N:C ratio with scant cytoplasm
• Nuclear molding and crush artifact
• Finely granular salt and pepper chromatin
• Necrosis and apoptotic debris frequently present

2nd look. 🧐
What is your diagnosis?
A) Small Cell Carcinoma
B) Adenocarcinoma
C) Granulomatous Inflammation
D) Hamartoma

🔬 #CytoQuiz
FNA Mediastinal Lymph Node
A) Carcinoma
B) Adenocarcinoma
C) Granuloma
D) Hamartoma

#CytoPath #Pathology 🙏 🖼️@IARCWHO

Tumid Lupus Erythematosus: Mucin + deep infiltrate + normal epidermis.
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Granuloma Annulare: Interstitial histiocytes + mucin + necrobiosis.
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Erythema Annulare Centrifugum: Coat-sleeve infiltrate + parakeratosis.
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Perniosis: Peri-eccrine lymphocytes + dermal edema.
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✅ Erythema Annulare Centrifugum
-Dense perivascular lymphocytic infiltrate
-Distinct "coat sleeve" or "pipe stem" arrangement
-Mounds of parakeratosis often present
-Variable spongiosis and focal vacuolar change

❌ Granuloma Annulare
-Interstitial lymphohistiocytic infiltrate ("busy dermis")
-Histiocytes arranged between collagen bundles
-Interstitial mucin and necrobiosis

❌ Tumid Lupus Erythematosus
-Superficial and deep lymphocytic infiltrate
-Prominent dermal mucin deposition
-Epidermis is typically unaffected (no interface change)

❌ Perniosis
-Superficial and deep perivascular lymphocytic infiltrate
-Aggregates around eccrine glands (peri-eccrine)
-Marked papillary dermal edema

2nd chance! High power.
What is the diagnosis?
A. Perniosis
B. Erythema Annulare Centrifugum
C. Tumid Lupus Erythematosus
D. Granuloma Annulare

#TooFarToDiagnose? 🧐
A. Perniosis
B. Erythema Annulare Centrifugum
C. Tumid Lupus Erythematosus
D. Granuloma Annulare

#Pathology #Dermatology #Dermatopathology #DermPath

Glomangioma: Dilated vessels + intramural glomus cells.
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Hidradenoma: Solid/cystic epithelial nodule + clear cells.
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Angioleiomyoma: Thick-walled vessels + smooth muscle fascicles.
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Myopericytoma: Concentric onion-skin growth around vessels.
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✅ Angioleiomyoma
-Well-circumscribed dermal/subcutaneous nodule
-Interlacing fascicles of mature smooth muscle
-Thick-walled vessels with slit-like lumens
-Blunt-ended "cigar" nuclei