In the present study,
DNA flow cytometry (FCM) and immunocytochemistry (ICC) with a selected panel of
antibodies were performed on 51 cases of malignant
tumors which were referred for fine-needle aspiration biopsy (FNAB) to our Department of Cytology for the last 2 yr. Twelve cases were diagnosed as
neuroblastoma, 16 as
Ewing's sarcoma, 2 as
retinoblastoma, 5 as
non-Hodgkin's lymphoma (NHL), 5 as
rhabdomyosarcoma, 2 as
peripheral neuroectodermal tumors (
PNETs), and 8 as
Wilms' tumor. Eleven of 12
neuroblastomas were diploid by FCM, and 1 was
aneuploid, with an S-phase fraction (SPF) of 8.3%.
Neuron-specific enolase (NSE) was negative in 3 and positive in 8 cases of
neuroblastoma, whereas
neuroblastoma marker was positive in 3/11. Sixteen of 17 Ewing's
sarcomas were diploid, and 1 showed
tetraploid aneuploidy, with an SPF of 10.06%. Eight of 13 Ewing's
sarcomas were positive for Mic-2 gene product (Ewing's marker). All 5 NHL were positive for
leukocyte-common antigen (LCA). Three of 5
rhabdomyosarcomas were diploid, and 2 cases showed
aneuploidy.
Rhabdomyosarcoma showed muscle-specific actin positivity in 4 and
desmin positivity in 3 cases. All 3 cases of
PNET were diploid and positive for the Mic-2 gene product, whereas NSE and
vimentin were positive in 2 cases. Both cases of
retinoblastoma were diploid. Immunostaining was noncontributory in 1 case, and the other showed positivity for the retinoblastoma gene product, NSE, and
chromogranin. Seven of 8 Wilms'
tumors were diploid, and 1 showed
aneuploid, with an SPF of 11.13%. Seven of 8 Wilms'
tumors were positive for
cytokeratin (CK), 5 were positive for NSE, 6 were positive for
epithelial membrane antigen (EMA), and 5 were positive for
vimentin. FNAB diagnosis of malignant round-cell
tumors is difficult only by light microscopy. Due to the availability of specific markers for subgrouping
tumors, ICC has proved to be more useful these days, while
DNA FCM has little diagnostic value, as most of them are diploid. Further ancillary studies, e.g., electron microscopy, image analysis, and other molecular investigations, are required to further categorize these
tumors more precisely for better clinical management of these cases.