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…
Particularly in or near nail bed • Solitary, slowly growing, and often long-standing lesion • Treatment: Complete excision • Excellent prognosis • Low rate of recurrence, usually related to incomplete excision Macroscopic • Usually <…
Endothelial cells may have cytoplasmic vacuolization May have solid appearance • Many eosinophils, lymphocytes, and mast cells, although eosinophil number can vary greatly Top Differential Diagnoses • Papillary endothelial hyperplasia • Kimura disease…
pN2a: Metastasis in single ipsilateral lymph node, > 3 cm to < 6 cm in greatest dimension pN2b: Metastasis in multiple ipsilateral lymph nodes, none > 6 cm in greatest…
Presents in infants or young children as multiple small vesicular lesions • Lymphangiomatosis Diffuse involvement of multiple organ systems, including skin, soft tissues, bone, and internal organs • Atypical vascular lesion (radiotherapy-related)…
