Extramedullary Hematopoiesis
EMH With MegakaryocyteThis is a skin biopsy specimen with extramedullary hematopoiesis (EMH), as evidenced by the large megakaryocyte . EMH With Erythroid CellsThis cutaneous lesion contains small clusters of nucleated…
Pseudoepitheliomatous Hyperplasia
Granular cell tumor Lymphoma • Reaction pattern in certain inflammatory conditions such as Lichen planus Lupus erythematosus • Reaction pattern overlying certain infections Particularly deep fungal • Reaction pattern overlying tattoos Particularly red…
Hobnail (Targetoid Hemosiderotic) Hemangioma
Hobnail HemangiomaLow-magnification view of a hobnail hemangioma (HH) demonstrates superficial dilated vascular spaces in the papillary dermis with deeper small blood vessels and stromal hemosiderin deposits . Higher Magnification of…
Apocrine Carcinoma (Apocrine Adenocarcinoma)
History of breast carcinoma May be indistinguishable histologically and immunohistochemically from apocrine carcinoma • Primary cutaneous adenoid cystic carcinoma Cribriform pattern within islands that are relatively uniform in size/shape and not…
Warty Dyskeratoma
Round to slightly oval nucleus with pink cytoplasm • Grains Raisinoid nuclei with pink cytoplasm • Minimal to no cytologic atypia Top Differential Diagnoses • Darier disease Histologically similar Clinically different – Multiple lesions…
Venous Lake
Related to chronic actinic damage • Head and neck • Especially common on lip • Can clinically mimic melanoma • Often multiple • Laser treatment Microscopic • Ectatic vessel in upper dermis • Usually single dilated vessel…
Angioleiomyoma
> 50% are painful • Treatment: Simple, conservative excision • Excellent prognosis; very rarely recurs Macroscopic • Usually < 2 cm Microscopic • Sharp circumscription • 3 types described: Solid (most common), venous, and cavernous…
Actinic Cheilitis
Full-thickness keratinocytic atypia, often with prominent suprabasilar mitoses and apoptotic figures • Squamous cell carcinoma (SCC) Invasive islands of atypical keratinocytes involving stroma Often associated with ulceration and dense inflammatory infiltrate…
Adult-Type Fibrosarcoma
Most tumors classified as fibrosarcoma in older literature now reclassified as other entities Must lack features of well-defined fibrosarcoma subtypes and other entities – Diagnosis of exclusion Lacks significant nuclear pleomorphism…
Tufted Angioma
Acquired Tufted Angioma at Scanning MagnificationScanning magnification of acquired tufted angioma (ATA) shows scattered lobular collections of vessels in the superficial and deep dermis. The lobules bulge into dilated vessels,…
