Man with multiple skin nodules. #pathology #dermpath #microbiology

Schwannoma (plexiform)! -Deep dermis/SQ -Encapsulated -Spindle cells -Cellular (Antoni A) & hypocellular (Antoni B) areas -Palisaded nuclei + intervening acellular zone (Verocay body) -May see degenerative atypia (ancient change) & hyalinized vessels S100+ #pathtwitter #dermpath

Bullous pemphigoid! -Subepidermal cleft + eosinophils -Linear IgG+C3 @ DEJ -Eosinophilic spongiosis may be only change in urticarial phase -Neutrophil rich & cell poor variants -Immunoreactant roof binding on salt split skin differentiates it from EBA #pathtwitter #dermpath

This is GOLD! #dermpath weatherman #ASDP21

Spindle cell lipoma👇🏻

Trichoepithelioma -BCC-like @ low power but: -Keratocysts -Follicular stroma -No peritumoral clefts -No atypia -Papillary mesenchymal bodies (arrow) -CD34+ stroma -Multiple: Multiple familial TEP, Brooke-Spiegler, Rombo & Bazex-Dupré-Christol syndromes #dermpath #pathtwitter

Flame figure! -Histiocytes, lymphocytes and degranulating eosinophils surrounding degenerated collagen -Classic in Well’s Syndrome but seen in: -Bug bites -Drug eruptions -Atopic dermatitis -AIBD -Hematologic dyscrasias -Hypereosinophilic syndrome and more! #dermpath #pathtwitter

A classic Myrmecia wart😀 -Palmoplantar skin -Hyperkeratosis -Large basophilic parakeratotic nuclei -Papillomatosis -Deep endophytic epidermal hyperplasia -In-turned rete ridges -Glassy, angulated, refractile cytoplasmic inclusions -HPV-1 #pathtwitter #dermpath

#bstpath #pathology

Young male with abrupt anhidrosis, -Painful sensations when hot -Hx of cholinergic urticaria Biopsy (anhidrotic area) Perieccrine CD3+ lymphocytes& normal eccrine coils Idiopathic Pure Sudomotor failure! -May have elevated IgE -Tx with systemic steroids #dermpath #pathtwitter

Merkel cell carcinoma! -Blue cells with 'watery' nuclei -Salt & pepper chromatin +/- intraepidermal component -CK20 (paranuclear dot), synaptophysin/chromogranin-A, MCPyV (+) -TTF-1 negative -Dual CK20/neurofilament expression: likely cutaneous origin #pathtwitter #dermpath

Here’s one we don’t see everyday -Suppurative granulomas -Morula (looks like a ⚽️) -PAS & GMS positive but not fungus Protothecosis! -Prototheca wickerhamii -Algal infection -Risk higher in immunosuppression -May cause olecranon bursitis #pathtwitter #dermpath #dermtwitter

This surprised me (not endemic here!) -Verrucous plaques on face -Pseudoepitheliomatous hyperplasia -Suppurative granulomas -Spherules <70 um with numerous endospores -Coccidioidomycosis! *Helpful to measure spherules (If >100 um entertain rhinosporidiosis) #pathtwitter #dermpath

A pretty syringocystadenoma papilliferum -Exoendophytic architecture -Papillary fronds lined by double layer of glandular epithelium -Stroma filled with plasma cells -Decapitation secretion -Often seen in association with nevus sebaceus #pathtwitter #dermpath #dermtwitter

Very nice article by Jerad Gardner, MD and Sara Shalin - Dr. Selim spoke on this at #ASDP21 #dermpath #pathology #dermatology

Happy New Year from this year's favorite pox! Molluscum contagiosum: -Central depression (often) -Endophytic lobular hyperplasia -Intracytoplasmic inclusions (Henderson-Patterson bodies) -Can have numerous large CD30+ lymphocytes (pseudolymphoma alert!) #pathtwitter #dermpath

I saw this and thought it deserved to be my first post of 2022! Scalp of a young child - Langerhans cell histiocytosis (LCH). Note the eosinophils and nuclear grooves. #pathology

Monomorphic itchy papules in axillae of female -Dilated follicle with parakeratotic plug -Infundibular spongiosis -Perifollicular lymphohistiocytic infiltrate (foamy histiocytes may be seen) -Subjacent dilated apocrine glands Fox-Fordyce Disease!🦊 #pathtwitter #dermpath

It’s been so long! I don’t get these too often, had to post -Dense foamy macrophages superficially -Elongate granulomas following the neurovascular bundles -Positive Fite stain Leprosy! (borderline) #dermpath #PathTwitter #pathologists #derm #dermatology

Relapsing-remitting necrotic papules in an HIV+ patient= Cryptococcosis (gelatinous reaction)! -Little inflammation -Mucoid tissue degeneration -Small yeasts 4-20um -PAS GMS mucicarmine + -Sometime has granulomatous reaction #PathTwitter #dermpath #pathology #dermtwitter