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…
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…
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…
> 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…
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…
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…
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,…
Typically does not show prominent storiforming of collagen, although it may be focally present in rare cases • Pleomorphic fibroma Pleomorphic cells are more prominent, and storiforming pattern of collagen should…
More cellular than acral fibrokeratoma Fascicles of spindled cells Lacks vertically oriented collagen bundles CD34(+) • Superficial acral fibromyxoma More cellular lesion Loose storiform to fascicular growth pattern Lacks vertically oriented…
Pilar Sheath AcanthomaScanning magnification of a pilar sheath acanthoma shows a dilated follicular structure lined by a thickened squamous epithelium with endophytic, lobulated areas . Pilar Sheath Acanthoma at Higher…
