Basicmedical Key

 Range: 0.3-6.5 cm Microscopic • Well circumscribed and lobulated • Mostly composed of mature hyaline cartilage • Variable amounts of calcification • Ossification common • Granulomatous inflammation in 15% of cases • Rare tumors with extensive…

 Considered to fall on morphologic spectrum with myopericytoma, myofibroma, and angioleiomyoma Clinical Issues • Most common in young adults (20-40 years) • Female predilection in subungual tumors • Most common in distal extremities…

 Cells are markedly enlarged and atypical to bizarre-appearing Top Differential Diagnoses • Melanoma in situ, superficial spreading type • Melanoma in situ, lentigo maligna type • Atypical (dysplastic) junctional melanocytic nevus • Irritated/traumatized nevi…

 Includes angiomyolipoma (AML), clear cell sugar tumor of lung (CCST), lymphangioleiomyomatosis (LAM), clear cell myomelanocytic tumor of falciform ligament/ligamentum teres Etiology/Pathogenesis • Only AML, CCST, and LAM are associated with tuberous…

 Spindle cells much more common  Epithelioid cells usually dispersed individually throughout lesion • Melanocytes “mature” by becoming smaller from superficial to deep • Kamino bodies: Eosinophilic globules at dermal-epidermal junction • Artifactual clefting…

 Enlarges after upper respiratory tract infection • Along anterior border of sternocleidomastoid muscle • Initial work-up of suspected branchial cleft anomaly (in order)  Intravenous or oral antibiotics (if infected), FNA, endoscopy &/or…

 Variable admixture of bland spindle cells, ropey collagen, mature adipose tissue, myxoid stroma, and mast cells • PL contains multinucleated tumor cells • Morphologic variants: Fat-free, fat-poor, angiomatous Ancillary Tests • CD34(+); loss…

 ~ 85% of all cases • Subset of cases arise in skin of other sites (trunk, arms, head and neck)  ~ 15% of cases • Single or multiple lesions at time of…