[19] The classic triphasic histology consisting of
blastemal, epithelial and mesenchymal component were observed in 61.1% of cases.
The group of SBRCT consists of numerous morphologically similar tumors including ES, rhabdomyosarcoma (RMS), neuroblastoma, small-cell osteosarcoma, lymphoblastic lymphoma (LBL),[5] poorly differentiated synovial sarcomas (PDSS), desmoplastic round cell tumor (DRCT), mesenchymal chondrosarcoma (MCS), and
blastemal predominant Wilms' tumor (WT).[6] These tumors make the diagnosis difficult because they may be histopathologically indistinguishable, particularly when poorly differentiated or in a small specimen of biopsy.
She underwent a right nephrectomy, and pathology reports identified a tumor measuring 9.2 x 7.0 x 6.5 cm with
blastemal, tubular, and mesenchymal components confined to the kidney.
While differential diagnosis included a
blastemal predominant Wilms Tumor and congenital mesoblastic nephroma, the tumor was determined to be most consistent with a rare ossifying renal tumor of infancy.
No
blastemal, skeletal muscle or clusters of clear cells were seen.
Obtained
blastemal samples were fixed in six different freshly prepared fixative solutions according to manufacturer's protocols (Suvarna et al., 2013).
Acinar differentiation, which is the most common, results in trypsin, chymotrypsin, lipase, and BCL10 positivity, making distinction from ACC challenging unless one identifies pathognomonic squamoid morules, and even primitive (
blastemal) elements.
The cellular origin of
blastemal cells, mechanisms of cellular release from mature tissue, dedifferentiation, accumulation of cells, blastema growth, and tissue patterning have all been the focus of extensive investigations.
Histopathological analysis revealed tumors with characteristics of nephroblastoma, presenting the classical triphasic histology, comprising the
blastemal tissue, hyperchromatic nuclei cells with scanty cytoplasm, primitive tubules, and glomeruli formation admixed with mesenchymal and epithelial cells (Figure 3).
All tumors were identified and categorized into
blastemal, epithelial, stromal, mixed type, and anaplasia by pathologist after excision, according to National Wilms' Tumor Study (NWTS).
Pathologically, Classical Wilms' tumour has triphasic histology, with components of
blastemal, epithelial, and stromal structures, as found in our case.
Igf2 mRNA has been shown to be expressed in
blastemal cells of the nephrogenic zone and in interstitial cells of the medullary region, and IGF2 has been shown to be involved in human renal development (7).