Primary intraosseous melanotic schwannoma of the fibula associated with the Carney complex.
Described herein is a rare case of intraosseous melanotic schwannoma (MS) occurring in a long bone of a 13-year-old girl with a loss of heterozygosity (LOH) at 17q22-24, which contains the PRKAR1A gene encoding the protein kinase A regulatory subunit 1-a. Plain radiography and magnetic resonance imaging revealed a 10 cm expansile osteolytic lesion involving the proximal fibula. An excisional biopsy revealed a cellular tumor consisting of mildly pleomorphic spindle or oval to polygonal cells with frequent intranuclear pseudoinclusions, intracytoplasmic melanin pigments, nuclear palisades, Verocay body-like structures, and psammomatous calcifications. The tumor cells showed strong immunoreactivity for S-100 protein, HMB-45, and neuron-specific enolase. Ultrastructurally, the tumor cells were invested by continuous, multiplied external lamina and conspicuous melanosomes in various stages of maturation. These observations were compatible with psammomatous melanotic schwannoma (PMS). In addition, the detection of LOH for PRKAR1A strongly suggests that PMS in the present case is a manifestation of the Carney complex (CNC).
Kim
Mi-Jung
MJ
Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Songpa-gu, Seoul, Korea.
Choi
Jene
J
Khang
Shin-Kwang
SK
Kim
Jung-Sun
JS
Lee
Jong-Seok
JS
Cho
Kyung-Ja
KJ
D000293:Adolescent; D001859:Bone Neoplasms / Q000150:complications / Q000473:pathology*; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics; D005260:Female; D005360:Fibula / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000378:metabolism; D019656:Loss of Heterozygosity; D008279:Magnetic Resonance Imaging; D008543:Melanins / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D009378:Neoplasms, Multiple Primary / Q000150:complications / Q000235:genetics*; D009442:Neurilemmoma / Q000150:complications / Q000473:pathology*; D013577:Syndrome
D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D008543:Melanins; C517834:PRKAR1A protein, human; D017868:Cyclic AMP-Dependent Protein Kinases