Dr. Jared Gardner's Dermatopathology Lecture: Case Study Review 🦠 ## Slide 1: Granulation Tissue - Draining nodule on the trunk that appeared cystic - Central cystic space without lining - Granulation tissue: - Big, plump endothelial cells - Inflammation: Neutrophils, eosinophils, histiocytes, lymphocytes - Fibrin lining the central space ## Slide 2: Non-Human Invasion - Identification of non-human cells/structures - Arthropod characteristics: - Exoskeleton - Yellowish-orange chitin - Granulation tissue response with eosinophils - Myiasis (Fly larva, botfly) ## Slide 3: Erythema Nodosum - Tender erythematous nodules in the lower extremities - Typically seen in young women - Paniculitis predominantly septal - Minimal inflammation in fat lobules - Enlarged, fibrotic septa - Granulomatous reaction with: - Histiocytes - Giant cells - Eosinophils - Biopsy techniques: - Double punch - Wedge biopsy ## Slide 4: Diffuse Neurofibroma - Condition in a patient with neurofibromatosis - Characteristics: - Fat entrapment - CD34, S100, SOX10 positive - Mimics Dermatofibrosarcoma protuberans - Presence of Wagner-Meissner-Meissner bodies - Rounded and spindled cells - Diagnosed by the cellular and morphological patterns ## Slide 5: Dermatofibrosarcoma Protuberans (DFSP) - Recognizable by story form pattern and spindle cells - Key features: - Bland spindle cells with story form pattern - Honeycomb pattern of fat entrapment - Negative for S100 and SOX10, CD34 positive - Differential diagnosis includes: - Dermatofibroma, Neurofibroma, Perineuroma - Solitary fibrous tumor (SFT) indicated by positive STAT6 ## Slide 6: Lichen Sclerosus - Typically found on the genital area - Histological characteristics: - Atrophic epidermis - Homogenized eosinophilic collagen - Inflammatory interstitial pattern akin to interstitial GA - Mimics of Mycosis Fungoides - Prominent epidermotropism of lymphocytes ## Slide 7: Differentiated Vulvar Intrepidial Neoplasia (D-VIN) - Acanthosis & hypergranulosis with basal layer atypia - Risk of progressing into invasive squamous cell carcinoma - P53 immunostaining used for diagnosis - Often not HPV related ## Slide 8: Condyloma Acuminatum - Appearance: - Rounded papillary surface - Parakeratosis and orthokeratosis - Dilated vessels in papillary dermis - Coelocytes with pale cytoplasm and large nuclei - Importance of accurate diagnosis due to social ramifications ## Slide 9: Tinea Capitis - Fungal infection particularly in hair shafts - Endothrix and ectothrix pattern - Characterized by: - Canidia spore forms - Replaced hair shaft with fungal hyphae - Common pathogens: Trichophyton rubrum Microsporum canis ## Slide 10: Encapsulated Fat Necrosis - Necrotic fat nodules surrounded by fibrosis - Post-traumatic origin - Characteristics of encapsulated area: - Foam cells - Histiocytes - Dead adipocytes - Can remain for years due to fibrosis encasing ## Slide 11: Gout & Pseudogout - Nodules with needle-shaped crystals (gout, monosodium urate) - Pale light feathery consistency - Washed out during processing - Rhomboid-shaped crystals indicative of pseudogout - Purple appearance in H&E sections - Polarizable under light - Ability to co-exist ## Slide 12: Clear Cell Acanthoma - Characterized by: - Elongated reedy, acanthotic cells - Sharp cut-off from surrounding epidermis - Pale cytoplasm - Neutrophils in epidermis - Notable for mimicry: Tricholemmomas, Inverted Follicular Keratoses, Poromas ## Slide 13: Tumid Lupus - Superficial and deep perivascular dermatitis with mucin - Can present with peri-adnexal pattern - Important absence of epidermal change and eosinophils - Mucin profound around adnexa ## Slide 14: Bowen's Disease - Squamous cell carcinoma in situ - Characteristics: - Severe pleomorphism - Highly atypical cells even at low magnification - Rarely extends to invasion but significant pleomorphism ## Conclusion - Overview of various pathologies - Erythema nodosum, Diffuse neurofibroma, DFSP, Lichen Sclerosus, D-VIN, Condyloma, Tinea Capitis, Encapsulated fat necrosis, Gout&Pseudogout, Clear Cell Acanthoma, Tumid Lupus, Bowen's Disease - Emphasis on characteristic patterns - Importance of immunostaining in difficult diagnoses