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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

Verruca vulgaris: Papillomatosis + toeing-in + tiers of parakeratosis. dpa-dapa.com/public/displ... Myrmecia: Eosinophilic inclusions + large keratohyalin granules. dpa-dapa.com/public/displ... Epidermodysplasia verruciformis2: Blue-gray cytoplasm + dysplasia. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

✅ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

✅ 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

000

Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

✅ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

❌ 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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 10/02/2026

🔬 #CytoQuiz FNA Mediastinal Lymph Node A) Carcinoma B) Adenocarcinoma C) Granuloma D) Hamartoma #CytoPath #Pathology 🙏 🖼️@IARCWHO

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

Tumid Lupus Erythematosus: Mucin + deep infiltrate + normal epidermis. dpa-dapa.com/public/displ... Granuloma Annulare: Interstitial histiocytes + mucin + necrobiosis. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

Erythema Annulare Centrifugum: Coat-sleeve infiltrate + parakeratosis. dpa-dapa.com/public/displ... Perniosis: Peri-eccrine lymphocytes + dermal edema. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

✅ 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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

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

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

Glomangioma: Dilated vessels + intramural glomus cells. dpa-dapa.com/public/displ... Hidradenoma: Solid/cystic epithelial nodule + clear cells. dpa-dapa.com/public/displ...

000

Charles Herndon @drcyclopath.bsky.social · 09/02/2026

Angioleiomyoma: Thick-walled vessels + smooth muscle fascicles. dpa-dapa.com/public/displ... Myopericytoma: Concentric onion-skin growth around vessels. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

✅ Angioleiomyoma -Well-circumscribed dermal/subcutaneous nodule -Interlacing fascicles of mature smooth muscle -Thick-walled vessels with slit-like lumens -Blunt-ended "cigar" nuclei

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

❌ Hidradenoma -Lobulated mass with solid and cystic areas -Biphasic: Polyhedral basophilic cells + Clear cells -Epithelial neoplasm (cytokeratin positive)

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

❌ Glomangioma -Dilated vascular spaces (cavernous-like) -Rows of uniform round glomus cells in vessel walls -Punched-out nuclei with pale cytoplasm

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

❌ Myopericytoma -Bland oval-to-spindle myoid cells -Multilayered concentric growth around vessels (onion-skinning) -Branching (HPC-like) vasculature

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

2nd chance! Lower power. What is the diagnosis? A. Myopericytoma B. Angioleiomyoma C. Glomangioma D. Hidradenoma

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Charles Herndon @drcyclopath.bsky.social · 09/02/2026

#TooCloseToDiagnose? 🧐 Painful subcutaneous nodule. A. Myopericytoma B. Angioleiomyoma C. Glomangioma D. Hidradenoma #Pathology #Dermatology #Dermatopathology #DermPath

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

Paget's Disease: Mucin positive + CK7 + eyeliner sign. dpa-dapa.com/public/displ... SCC in situ (Bowen's) dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

Clear Cell Acanthoma: Sharp demarcation + neutrophils + adnexal sparing. dpa-dapa.com/public/displ... Trichilemmoma: Thickened basement membrane + CD34. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

✅ Clear Cell Acanthoma -Psoriasiform hyperplasia with sharp "cliff-drop" demarcation -Neutrophils in stratum corneum (often abundant) -Clear cells due to abundant glycogen (PAS positive, digested by diastase) -Sparing of the acrosyringium/adnexa

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ Paget's Disease -Large atypical cells singly and in nests (buckshot) -Crushed basal layer (eyeliner sign) -Cytoplasm often contains mucin (PAS-D resistant)

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ SCC in situ (Bowen's) -Full thickness atypia (windblown appearance) -Clear cell change can be seen due to glycogen (PAS sensitive) -Nuclei are usually central or pleomorphic, not scalloped

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ Trichilemmoma -Lobular proliferation hanging from epidermis -Peripheral palisading with thickened basement membrane

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

2nd chance! Lower power. What is the diagnosis? A. Clear Cell Acanthoma B. Trichilemmoma C. Bowen's Disease D. Paget's Disease

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

#TooCloseToDiagnose? 🧐 A. Clear Cell Acanthoma B. Trichilemmoma C. Bowen's Disease D. Paget's Disease #Pathology #Dermatology #Dermatopathology #DermPath

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

Lymphangioma: Lymphatic channels + deep cisterns + proteinaceous fluid. dpa-dapa.com/public/displ... Targetoid Hemosiderotic Hemangioma: Hobnail cells + biphasic pattern + hemosiderin. dpa-dapa.com/public/displ...

000

Charles Herndon @drcyclopath.bsky.social · 04/02/2026

Verrucous Hemangioma: Deep dermal/subcutaneous extension mimicking angiokeratoma. dpa-dapa.com/public/displ... Angiokeratoma: Superficial papillary dermal vessels with epidermal collarette. dpa-dapa.com/public/displ...

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

✅ Verrucous Hemangioma -Surface mimics angiokeratoma (hyperkeratosis/acanthosis) -Crucial difference: extends deep into reticular dermis/subcutis -Lobular architecture common in deep dermis -Requires wide excision (high recurrence rate)

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ Targetoid Hemosiderotic Hemangioma -Hobnail endothelial cells protrude into lumen -Biphasic: Dilated superficial, compressed deep -Prominent hemosiderin deposition

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ Lymphangioma -Dilated lymphatics in papillary dermis (frog spawn) -Deep extension to muscular cisterns (iceberg effect) -Lumen contains proteinaceous fluid/lymphocytes

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

❌ Angiokeratoma -Dilated vessels strictly limited to papillary dermis -Epidermal collarette "embracing" the vessels -Lumen packed with erythrocytes/thrombi

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Charles Herndon @drcyclopath.bsky.social · 04/02/2026

2nd chance! What is the diagnosis? A. Angiokeratoma B. Lymphangioma C. Verrucous Hemangioma D. Targetoid Hemosiderotic Hemangioma

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