Both of these tumors exhibited "large cell neuroblastoma" histology with enlarged, uniquely open nuclei and nucleolar hypertrophy, along with "aberrant" desmin expression.
Histopathological findings showed neuroblastoma and immunohistochemical results were as follows: actin(-), CD34(-), CD99(-), CK(-), CgA(+), desmin(-), EMA(-), Ki-67(+, approximately 1%), NSE(+), S-100(+), Syn(+), and vimentin(-).
It is one of the pediatric small round blue cell tumors, characterized by strong membrane expression of CD99 in a chain-mail pattern and negativity for lymphoid (CD45), rhabdomyosarcoma (myogenin, desmin, actin) and neuroblastoma (neurofilament protein) markers.
In this study, the expressions of smooth muscle-specific proteins (desmin, alpha-smooth muscle actin, basic calponin and the smooth muscle myosin heavy-chain isoforms of SM1 and SM2) in three parent and four cloned neuroblastoma cell lines, composed of S-type cells, were examined by indirect immunofluorescence, Western blot and/or by reverse transcription-polymerase chain reaction (RT-PCR).